APEX: Neuro - Spinal Cord, APEX: Neuro - Brain, APEX: Regional UE, Unit 8 Regional Flashcards (Lower Extremity) Apex, Upper extremity blocks, Lower Extremity Regional Apex, APEX Regional Flashcards (Upper Extremity), APEX Regional Flashcards (Neuraxi...
Systemic lupus affect nearly every organ system, most of the consequences are the direct result of what?
Direct result of antibody induced vasculitis and tissue destruction
What may the patient feel with a caudal block setting up?
Fullness in sacrum (normal response)
(2) contraindications for hypokalemic periodic paralysis?
Furosemide Glucose infusion
Calculate expected PAO2 when the PaCO2= 80mmHg, FiO2= 28%, and A-a gradient is 35
PAO2 = (FiO2 x (Pb - PH20) - (PaCO2/RQ) 0.28 x(760-47) - (80/0.8) 200-100 = 100mmHg 100mmHg - 35(A-a gradient) = 65mmHg
Factors that increase risk of TNS
Lidocaine, lithotomy position, ambulatory surgery, knee arthroscopy
*Lipophilic* Opioids: Nausea + vomiting
Lower incidence
Rank opthalmic anesthetic technique according to the amount of pain caused by the procedure(lowest to highest) (retrobulbar, peribulbar, topical, sub-tenon)
Lowest-topical subtenon, peribulbar, retrobulbar-highest
The *psoas compartment* contains the ______________ plexus within a sheath.
Lumbar
The psoas compartment contains the ______________ plexus within a sheath.
Lumbar
Treatment of Guillain-Barre: What does not improve GB?
Plasmapheresis and/or IV IgG Steroids and interferon (they do work for multiple sclerosis)
Ligamentum flavum
Run the length of the spinal canal To Form dorsolateral margins of epidural space thickest in the lumbar region
Supraspinous ligament
Runs most of the length of the spine and joins tips of the spinous process
myasthenia gravis and pregnancy
Symptoms get worse (30% of pts) and antibodies can cross placenta - baby may need airway support after delivery and weakness may last 2-4 weeks.
Absent seizure (petit mal)
Temporary loss of awareness -more common in children
Akinetic seizure
Temporary loss of consciousness and postural tone More common in children
What places does rheumatoid arthritis in the airway
Temporomandibular joint - mouth opening Cricoarytenoid joints - decreased diameter of glottic opening Cervical Spine - Atlanto-occipital subluxation
Cerebral autoregulation definition -Formula for cerebral blood flow
The brains ability to maintain a constant cerebral blood flow over a wide range of mean arterial blood pressures CBF = Cerebral perfusion pressure/Cerebral vascular resistance -Benefit: ensures steady supply of O2 even with blood pressure fluctuations
What is used to monitor for the development of vasospasm?
Transcranial Doppler exams
Describe the relationship of the terminal branches relative to the axillary artery
The axillary block targets 4 terminal branches of the BP as they course distally w/ the axillary a. and axillary v. along the humerus from the apex of the axilla - musculocutaneous n is anterior + lateral - median n. is anterior and medial - radial n. is posterior and lateral - ulnar n. is posterior and medial
Which muscles surround the neurovascular bundle in regards to an axillary block?
The biceps brachii (lateral and superficial), the coracobrachialis (lateral and deep), and the triceps brachii (medial and posterior).
What is cerebral salt-wasting syndrome? How do you treat it?
The brain releases natriuretic peptide, leading to volume contraction, hyponatremia, and sodium wasting by the kidney Treat with isotonic crystalloids *contrast SIADH is caused by euvolemia or hypervolemia and is treated by fluid restriction
Identify the area of defection that causes malignant hyperthermia
The defective ryanodine receptor (RyR1) instructs the sarcoplasmic reticulum to release excessive amount of calcium.
What are used as landmarks for blocks?
Traditional nerve block techniques are based on the ability to palpate muscles, bones, and pulses.
What are the 4 major side effects of neuraxial opioids?
1. Pruritus (most common) 2. Resp depression (hydrophilic drugs worse d/t rostral spread) 3. Urinary retention 4. N/V
Hypobaric
lower density than CSF - rises
Ropivacaine onset, anesthesia, and analgesia
onset 15-30 min, anesthesia duration 5-10 hrs, analgesia duration 16-18 hrs
What does a wake up test, test for?
paraplegia This has been replaced by MEP & SSEP
Third order neuron (Anterolateral)
pass through the internal capsule and advance toward the somatosensory cortex in the postcentral gyrus in the parietal lobe Most pain fibers synapse in the RAS and then connect to the thalamus
Third order neuron (Dorsal)
pass through the internal capsule and advance towards the somatosensory cortex in the postcentral gyrus in the parietal lobe
Sign of pneumo
patient coughs or complains of pain at needle insertion
Transient Neurologic Symptoms (TNS) cause
patient positioning stretching of the sciatic nerve myofascial strain muscle spasm
The obturator n. is prone to injury during extensive _________________ surgery.
pelvic
Anesthetic considerations for AVM include: AVMs are more common in ___
younger population open repair has higher blood loss seizures as a result of vascular steal syndrome
Complications of non-cutting
requires more force
According to the American society of anesthesiologists, what is the incidence of anesthetic mortality in the asa1 patient population?
.04 per 10000 anesthetics
What is the angle of a Crawford needle?
0 degrees
Morphine Intrathecal dose Epidural dose Epidural Infusion dose
0.25 - 0.30 mg 2 - 5 mg 0.1 - 1 mg/hr
Landmarks for the Infraclavicular Block
1 = coracoid process 2 = clavicle 3 = humerus 4 = scapula
Where is the *deep peroneal n.* blocked?
Between the tendons of the anterior tibial and extensor digitorum longus muscles
What is the proposed mechanism for HoTN + bradycardia during shoulder arthroscopy w/ an interscalene block?
Bezold-Jarisch reflex
Paget's disease
Excess osteoblastic and osteoclastic activity tinnitus, bone pain, enlargement of bone, thick bones Cause: Excessive parathyroid hormone or calcitonin deficiency Can cause peripheral nerve entrapment NO vascular involvement
Metabolism/elimination of gabapentin
Excreted unchanged via the kidneys
Gabapentinoids (Gabapentin, Pregablin) MOA, metabolism
Inhibition of the alpha 2 delta subunit of voltage gated calcium channels in the CNS - ↓ excitatory nt release -not a GABA agonist and does not get metabolized to GABA Excreted unchanged in the kidneys, do not cause hepatic induction Also useful for neuropathic pain
What may occur with simultaneous administration of valproic acid and phenytoin?
Inhibits phenytoin metabolism - displaces from plasma proteins
Where do you inject LA for a *median n.* block at the wrist?
Inject 5mL btwn the flexor carpi radialis tendon and the flexor palmaris longus tendon
How do you block the *radial n*. in the forearm? Volume in ml? Where does it derive from?
Inject btwn *biceps tendon* and *brachioradialis* Volume = 3-5mL -posterior cord brachial plexus
How is c6 neuropathy developed?
Injecting LA into the neuron - compresses the nerve root against tubercle pts may develop crampy sensation
Most common sign of Subarachnoid Hemorrhage (SAH)
Intense headache "worst one in my life" Consciousness lost in 50% Other s/sx: focal deficits, N/V, photophobia, fever
Axillary indications and landmarks
Indications: forearm & hand Landmarks: axillary artery pulse, coracobrachialis muscle 9 (musculocutaneous nerve passes thru it), humerus
Contraindication for bier block
Infection of extremity Poor circulation Seizure disorder Heart Block Allergy
Ehlers-Danlos syndrome definition
Inherited disorder of procollagen and collagen (spontaneous bleeding into joints and AAA)
MOA of neuraxial opioids
Inhibit afferent pain transmission in substantia gelatinosa (lamina II) of the dorsal horn Epidural opioids also diffuse into systemic circulation, where blood delivers them to opioid receptors throughout the body
Anti-rheumatic drug MOA
Inhibit tumor necrosis factor (TNF), interleukin-1 & 6 Inhibits T cells & B lymphocytes (Immunosuppresant) Methotrexate, cyclosporine, etanercept methotrexate causes liver dysfxn & suppresses bone marrow Cyclosporine prolongs duration of Succ
MOA of gabapentin
Inhibition of alpha 2-delta subunit of ca+ channels in the CNS --> decreased excitatory NT release
In addition to a Brachial Plexus block, which nerve must also be anesthetized for a patient to tolerate an UE Tourniquet?
Intercostobrachial n. - arises from T2
Which arteries supply the anterior circulation of the brain? Order?
Internal carotid arteries Aorta-->Carotid a--> Internal carotid a.--> Circle of Willis--> Cerebral hemispheres
Which UE block approach often blocks the stellate ganglion?
Interscalene block
Which BP block is most likely to cause *phrenic nerve paralysis*?
Interscalene block (ipsilateral hemiparesis of diaphragm)
What artery is most likely to be inadvertently injected with each brachial plexus block
Interscalene: Vertebral Supraclavicular: Subclavian Infraclavicular: Subclavian or axillary Axillary: Axillary
Lipid rescue protocol:
Intralipid 20% 1.5ml/kg over 1min then infusion .25ml/kg/min
What is another name for a *psoas compartment* block?
Lumbar plexus block
Which choice is the MOST potent amnestic? Choices:Diazepam, Midazolam, Flurazepam, Lorazepam
Lorazepam (up to 6hrs of amnesia)
Selegiline
MAO-B inhibitor Restores dopamine concentration by reducing dopamine metabolism in the CNS *Does not increase the risk of tyramine-induced hypertensive crisis
Selegiline
MAO-B inhibitor = inhibits the metabolism of dopamine in the basal ganglia
_____ pushes outward against aneurysmal sac, ______ is the counter pressure that pushes against. ______ creates tamponade effect.
MAP ICP ICP
Transmural pressure equation
MAP - ICP
Occular perfusion pressure
MAP - IOP
absolute contraindications to ECT include
MI within 4-6weeks stoke within 3 months intracranial surgery within 3months brain tumor unstable cervical spine pheochromocytoma
C sympathetic peripheral nerve fibers
No myelination Function: Postganglionic ANS fibers Diameter: 0.3 - 1.3 µm Velocity: Slowest Block onset: second
C Nerve Fiber (sympathetic) -Myelination -Function -Diameter -Conduction velocity -Block onset
No myelination Function: Postganglionic ANS 0.3 - 1.3 + 2nd
Which nerve is most commonly missed in a 3-in-1 block?
Obturator n.
The anterolateral system (spinothalmic tract) transmits what type of sensations?
Pain, temp, crude touch, tickle, itch, sexual sensation
Treatment for Alzheimer's
Palliative- aims to restore concentration of Ach Cholinesterase inhibitors such as tacrine, donepezil, rivastigmine, and galantamine
Where do third order neurons of the dorsal column travel?
Pass through the internal capsule and advance toward the somatosensory cortex in the post central gyrus in the parietal lobe
NO EFFECT on Risk of PDPH
Patient Factors - early ambulation Provider Factors - continuous spinal cath (if placed after spinal block)
Methods to protect against dysrhythmias with MH
Procainamide 15mg/kg IV Lidocaine 2mg/kg IV Do NOT give a CCB - can precipitate life-threatening hyperkalemia
What is auto regulation influenced by?
Products of local metabolism, myogenic mechanisms(vascular smooth muscle contraction), and autonomic innervation
Pyridostigmine ____________ the duration of Succ
Prolongs It impairs the efficacy of pseudocholinesterases
Median nerve movement
Pronation of forearm Flexion of wrist Opposition of the middle, forefinger and thumb
Procedure risk factors for ION
Prone, Wilson frame, long duration of anesthesia, large blood loss, low ratio of colloid:crystalloid, hypotension
Intraoperative BP during aneurysm surgery
SBP: 120-150mmHg High normal BP is required to perfuse collateral vessels while clamp is on If no clamp is use, controlled hypotension may be requested to prevent aneurysm rupture
Anesthetic consideration for sickle cell anemia
SC disease (homozygous) not SC trait (heterozygous) increases risk of mortality. pain, hypothermia, acidosis, dehydration increase sickling
Where does the spinal cord end?
SC ends in a taper as the conus medullaris
*Interscalene block* Ultrasound Image
SCM= Sternocleidomastoid ASM= anterior scalene MSM= Middle scalene
Cerebral Perfusion Pressure SBP range and MAP range -Formula
SBP 50-150 mmHg OR MAP 60-160 mmHg CPP = MAP-ICP (or CVP, whichever is higher)
What will you see on the screen with short axis imaging?
Short axis will see dots Ex: if doing an US on a radial artery, will show up as a DOT
What procedures are not well suited for a *supraclavicular block*?
Shoulder surgeries - does not anesthetize the suprascapular n., which arises from the proximal upper trunk
What does a Cobb angle of 100 indicate
Significant gas exchange impairment and higher risk of postop pulmonary complications
Caudal Block technique
Sims position prone: Roll under iliac crest, Legs In frog position 22 To 25 gauge needle Or 20 gauge IV catheter Bevel up Through sacral hiatus at 45° angle Advancing to feel a pop, Drop angle
When is the BBB dysfunctional?
Sites of tumor, injury, infection, or ischemia
What occurs when CPP is less than 50?
Vessels are maximally dilated CBF becomes pressure dependent Risk of cerebral hypoperfusion
Cranial Nerve VIII -Nerve name -Function -Bedside test
Vestibulocochlear Sensory Hearing and balance
What is the function of Pacinian corpuscles?
Vibration
3 factors that disrupt autoregulation
Volatile anesthetics Head trauma Intracranial tumor
Primary determinant of spread in epidural anesthesia
Volume
What determines the height of a sacral block?
Volume
Jacksonian march
When a partial seizure progresses to a generalized seizure
When is the psoas block useful? (2)
When neuraxial anesthesia is contraindicated Want anesthesia to one lower extremity only
Diagnosis for AO subluxation
When the distance between the anterior arch of the atlas and the otonoid process is > 3mm
Glasgow Coma Scale (GCS)
a scoring system used to describe the level of consciousness in a person following a traumatic brain injury
Match each blood type with the corresponding antibody you would find in its serum: a) A b) AB c) B d) O
a) A - antiB b) AB - none c) B - antiA d) O - anti A and B
Which is expected to decrease in the elderly?
PaO2
DOPA decarboxylase facilitates conversion of:
DOPA to dopamine
What blocks can you not use epi in?
Digit or end-organ (ears, toes, penis, fingers)
Renal complications of RA
Renal insufficiency d/t vasculitis and NSAIDs
Where do the internal carotids enter the skull? (Anterior circulation)
Through the foramen lacerum
Where do the vertebrals enter the skull? (Posterior circulation)
Through the foramen magnum
Which gland plays a key role in myasthenia gravis? What brings relief of symptoms?
Thymus gland; thymectomy
Differential diagnosis of MH v. other possibilities *just to be aware
Thyroid storm Malignant neuroleptic syndrome Sepsis Pheochromocytoma Serotonergic syndrome Heat stroke metastatic carcinoid Cocaine intoxication
MH differential diagnosis
Thyroid storm Neuroleptic malignant syndrome Pheochromocytoma Sepsis Serotonergic syndrome Heat stroke Metastatic Carcinoid Cocaine intoxication
Match ADP receptor inhibitor with the number of days it should be discontinued prior to elective surgery Ticlopidine, ticagrelor, clopidogrel, prasugrel
Ticagrelor- 1-2days Prasugrel- 2-3days Clopidogrel- 7days Ticlopidine- 14days all are metabolized by the liver
What lung volumes increase in the pregnant patient? (2)
Tidal volume (30%) Inspiratory reserve volume
T/F, an axillary block may require more multiple injections?
True
What do the trunks divide into?
Trunks divide into Anterior and Posterior Divisions
Where do the trunks turn into divisions?
Trunks split into divisions *underneath clavicle* and *over 1st rib*
List the branches of CN VII and function
Two zebras bit my cat Temporal Zygomatic Buccal Mandibular Cervical Both motor and sensory Facial movement, eyelid closing, taste for anterior 2/3 of tongue
What is the function of Meissner's corpuscles?
Two-point discriminative touch and vibration
Oligodendrocytes
Type of glial cell in the CNS that wrap axons in a myelin sheath. Schwan cells form the myelin sheath in the PNS
CREST syndrome
Type of scleroderma Calcinosis, Raynaud's, esophageal dysmotility, Sclerodactyly, Telangiectasia
GI complications of RA
Ulceration d/t NSAIDs and steroids
what will you see in a block/lesion to the ulnar nerve ?
Ulnar (C 8, T1) *"Clawing"* of fingers 3 & 4- M.P. joints hyper extended; Thumb - abducted and extended - adductor pollices. Sensory Deficit- Ulnar and dorsal aspect of palm and of ulnar 1 1/2 digits
This nerve is derived from the medial cord. Motor innervation is mainly to intrinsic muscles of the hand. Sensory innervation is from the medial ( ulnar) 1 & 1/2 digits ( the 5th. and 1/2 of the 4th. digits). Claw hand.
Ulnar nerve [Claw hand, 'pope benediction']
What does the interscalene not block?
Ulnar nerve. Less suitable for procedures on the hand b/c C8-T1 harder to block from this approach *Ulnar nerve is often missed when doing an interscalene block*
T10 sensory innervation
Umbilicus
Contraindications to peripheral nerve blocks:
Uncooperative patient Patient refusal Sedated Patient Bleeding disorders/abnormalities Infection Local anesthetic allergy or toxicity Peripheral neuropathies
Target pressure following ischemic CVA
Under 185/110 Fluid replacement supports, BP,CO, CPP- also improves CBF by decreasing viscosity
Wernicke's area
Understanding speech
The cause of Familial periodic paralysis is:
Unknown
Which laminae are motor?
VII - IX
Which nerve is responsible for 75% of all parasympathetic activity?
Vagus
Cranial Nerve X -Nerve name -Function -Bedside test
Vagus Both Swallowing
What cardiac pathologists present a risk of HD collapse with neuraxial anesthesia?
Valve lesions w/ fixed SV: - severe aortic stenosis - severe mitral stenosis - hypertrophic cardiomyopathy
What is Batson's plexus? What is its significance?
Valveless epidural veins that drain venous blood from the spinal cord passing through anterior and lateral regions of epidural space Obesity + pregnancy increase intra-abd pressure, causing engorgement of the plexus - Increased risk of needle injury/cannulation during neuraxial techniques
Most significant source of morbidity and mortality in a patient with SAH
Vasospasm
Compared to the adult, which is higher in the newborn (2)
Vd for water soluble drugs Extracellular fluid volume
basal ganglia
fine control of movement
Acceptable response to twitch monitor (infraclavicular)
finger twitch
injury below the level of decussation in the medulla
flaccid paralysis on the ipsilateral side of the body
Guillain-Barre clinical presentation & Cause
flu-like symptoms precede paralysis Cause: Camplyobacter jejuni bacteria, Epstein Barr virus, Cytomegalovirus. Other causes: vaccinations, surgery, lymphomatous disease
TIA
focal neurologic deficit that spontaneously resolves w/in 24h
Cranial border of the epidural space
foramen magnum
How does Epi affect LA?
induces local vasoconstriction so slows blood absorption therefore prolongs duration
Bier blocks are best used in surgeries that have minimal:
post operative pain bc the lidocaine gets flushed out with tourniquet release
Lumbar spinous process project in a _________ direction
posterior Makes access easier
Cords
posterior: C5-T1 medial: C5-C7 lateral: C8 -T1
What can lessen the risk of bezold jarisch reflex?
preop Beta blockade
Cerebral blood flow graph: which represents ICP
A-PaO2 B- PaCO2 C- CPP D- ICP
What causes restrictive lung disease in Duchenne?
Kyphoscoliosis, which decreases pulmonary reserve
Which nerve roots give rise to the *iliohypogastric nerve*?
L 1
Which nerve roots give rise to the *ilioinguinal nerve*?
L1
Which nerve roots give rise to the *genitofemoral nerve*?
L1 + L2
Focal cortical seizure
Localized to one cortical region can be motor or sensory Usually no loss of consciousness
Broca's area location and function
Located in temporal lobe Motor control of speech
Wernicke's area location and function
Located in temporal lobe Understanding speech
*Hydrophilic* Opioids: Duration
Longer (6 - 24 hours)
*Lipophilic* Opioids: Pruritus
Lower incidence
Benefits of non-cutting tip
Lowers risk of PDPH More tactile feel Needle less likely to deflect Less likely to injure the cauda equina
The superior iliac spine coincides with:
S2 Location of the dural sac in adults Neonates dural sac: S3
What is the MAC of isoflurane in the full term parturient (pregnant)?
0.6% in FT pregnant pt MAC is reduced 40%
Crawford epidural needle
0°
spinal cord circulation
2 posterior spinal arteries 1 anterior spinal artery 6-8 radicular arteries
Which LA can REDUCE the EFFICACY of EPIDURAL opioids?
2-Chloroprocaine
Max does of Bupivicaine for peripheral nerve block?
2.5 mg/kg or 250 mg
For peds specifically, any concentration of bupi, levobupi, ropivacaine can be used as long as total dose doesnt exceed
2.5-3 mg/kg
Dantrolene dose
2.5mg/kg IV, repeat q 5-10min if pt requires more than 20mg/kg reconsider diagnosis
What volume of LA is appropriate for a *psoas compartment* block?
20 - 30 mL
MRI scanner should be located in zone:
4 - very limited access with very strict supervision
Cobb angle wwhen respiratory s/s appear
70
Cobb angle associated with pulmonary symptoms
70 degrees
Microglia
Act as phagocytes, eating damaged cells and bacteria, act as the brains immune system
TIA
"Mini stroke" - focal neurologic deficit that spontaneously resolves within 24 hours
Draw the femoral triangle
"SAIL" of a ship S = Sartorius m. A = Adductor longus m. IL = Inguinal ligament
Ganglion
A collection of cell bodies that reside outside of the CNS
What connects the hemispheres of the brain?
Corpus callosum -Located deep in the longitudinal fissure
Brachial plexus [image]
Be able to draw this!
Roots
C5-T1
Earliest symptoms of myasthenia gravis
Diplopia(double vision), ptosis (eye droop)
Musculocutaneous nerve mvmt.
Flexion at elbow
Which nerve is not anesthetized with any approach of the brachial plexus block?
Intercostobrachial nerve
complications of the Infraclavicular Block?
Pneumothorax, Chylothorax , Hemothorax
*Lipophilic* Opioids: Duration
Shorter (2 - 4 hours)
*Lipophilic* Opioids: Onset
Fast (5 - 10 min) *fentanyl, sufentanil
Clinical presentation of Guillain-Barre
Flu-like illness precedes paralysis by 1-3 weeks
What phenomenon occurs when the stellate ganglion is blocked?
Horner's Syndrome
Jet Ventilation
can be used above the glottis can cause a pneumothorax
ganglion
collection of nerve cell bodies that reside outside of the CNS
mitral insufficiency is associated with
eccentric hypertrophy and volume overload
Scleroderma
excessive fibrosis in skin and organs
What do you want to see if interscalene block in right place?
Looking for hand, arm and bicep contraction
What structures reside in the adrenal medulla? (2)
Loop of Henle Collecting ducts
Sacral Cornua -Definition -Result from
-Boney nodules that flank the sacral hiatus -Result from the incomplete development of the facets
VAE signs
↑EtCO2 ↑EtCO2 & PaCO2 gradient
Describe the anatomical position of the *femoral n.*
- biggest of the 3 nerves - forms near middle and lower 3rd of psoas muscle - courses distally in groove created by psoas major and iliac muscle - continues under inguinal ligament - lies anterior to iliopsoas muscle, lateral to to femoral a.
Describe the 3 signs/symptoms of the *Bezold-Jarisch* reflex
- bradycardia - HoTN - syncope
An *interscalene block* is NOT good for procedures below the __________, as it frequently spares roots ____________.
- elbow - C8-T1 (lower trunk)
Sphenopalatine ganglion block
1 to 2% lidocaine or 0.5% Bupivacaine Sniffing position Leave cotton tipped applicator in nose 5 to 10 minutes
Multiple sclerosis 4 anesthetic implications to know
1) spinals can exacerbate symptoms 2)hyperthermia can exacerbate symptoms 3) succinylcholine can cause hyperkalemia 4) seroids are useful for MS
How long may neurogenic shock last?
1-3 weeks (neurogenic shock for a few weeks, then dysreflexia may happen when there is stimulation)
4 cardinal signs of Parkinson's
1. Resting "pill rolling" tremor 2. Rigidity (increased muscle tone) 3. Bradykinesia (slowed movement) 4. Postural instability - loss of balance w/ altered gait 2 of the 4 signs is diagnostic
What are the 2 complications of a *psoas compartment* block?
1. Retroperitoneal hematoma 2. Renal capsular injection
Major Anesthetic considerations for Gullian Barre (3)
1. Skeletal muscle denervation 2.Impaired ventilation 3. Autonomic dysfunction
What are the 3 ABSOLUTE contraindications to caudal anesthesia?
1. Spina bifida 2. Meningomyelocele of sacrum 3. Meningitis
Rank the opioids from most lipophilic to most hydrophilic
1. Sufenta 2. Fentanyl 3. Meperidine 4. Hydromorphone 5. Morphine
5 ligaments of the spinal column in order from superficial to deep
1. Supraspinous ligament 2. Interspinous ligament 3. ligamentum flavum 4. Posterior longitudinal ligament 5. Anterior longitudinal ligament
Consequences of increased intracellular calcium
1. Sustained muscle contraction 2. Accelerated metabolic rate and rapid depletion of ATP 3. Increased O2 consumption 4. Increased heat & CO2 production 5. Mixed respiratory and metabolic acidosis 6. Sarcolemma breaks down 7. Potassium and myoglobin leak into systemic circulation 8. Rigidity and sustained contraction
Postoperative concerns for myasthenia gravis (3)
1. Very sensitive to effects of residual NMBlockade 2. Bulbar muscle weakness (mouth and throat)- difficulty handling oral secretions- increased risk for aspiration 3. May need postop mechanical ventilation- need to let patients know its a risk
Urinary retention caused by neuraxial opioids: More common young males/females? More common in IV/IM/Neuraxial? Results from inhibition of: What reverses it?
1. Young males 2.Neuraxial 3. Inhibition of sacral parasympathetic tone- causes bladder detrusor muscle relaxation and urinary sphincter contraction 4.Reverse with naloxone
What are the 2 most common side effects of an epidural blood patch?
1. backache 2. radicular pain
Order of CSF flow
1. choroid plexus 2. lateral ventricles 3. 3rd ventricle 4. Aqueduct of Sylvias 5. 4th ventricle 6. Foramen of Luschka 7. Foramen of Megendie 8. subarachnoid space + central canal -> superior sagittal sinus
4 sites of brain herniation
1. cingulate gyrus under the falx 2. tentorium cerebelli (transtentorial) 3. cerebellar tonsils through the foramen magnum 4. through the site of surgery or head trauma (ie an unnatural opening in the skull)
Interscalene landmarks [image]
1. clavicle 2. posterior border of the sternocleidomastoid muscle 3. EJ 4. Cricoid Cartilage C6 =adams apple.
Relative contraindications to neuraxial anesthesia
1. coagulopathy: risk of hematoma, PLT < 100,000, PTT, aPTT, or bleeding time twice normal level 2. ↑ICP = change is CSF pressure 3. Sepsis 4. Infection at the puncture site 5. Hypovolemia = worsening of HoTN d/t sympathectomy 6. Scoliosis, arthritis, spinal fusion, osteoporosis (technical difficulty) 7. Difficult airway = complicates quickly converting to GA if block fails 8. Peripheral neuropathy = slow recovery, more susceptible to injury 9. Multiple sclerosis = epidural is safe but intrathecal may cause exacerbation (an NCE thing - not true in practice)
Treatment of neurogenic shock
1. fluid resuscitation 2. atropine 3. vasopressor (norepi) No Succ (esp. 24 after time of injury)
What increases the risk of respiratory depression w/ neuraxial opioids
1. higher doses 2. co-administered sedatives 3. low lipid solubility 4. advances age 5. opioid naivety 6. increased intrathoracic pressure
Order of recovery in differential blockade
1. motor 2. touch 3. pinprick (fast pain) 4. Temperature 5. pre-ganglionic sympathetic Anesthetized in the opposite order
Morbidity related to SAH is usually the result of...
1. obstructive hydrocephalus 2. rebleeding 3.vasospasm
The sciatic n. MOTOR innervation: Provides motor and sensory info to:
1. posterior thigh 2. lower leg + foot via branches (tibial + common peroneal)
myasthenia gravis postoperative concerns
1. sensitive to residual effect of nmb's 2. bulbar muscle weakness -> increased risk of pulmonary aspiration 3. possible postop mechanical ventilation
Methods to reduce ICP
1. ↓Cerebral blood volume 2. ↓CSF 3. ↓cerebral edema 4. ↓cerebral mass
How far should you advance the epidural catheter? -too shallow -too deep
3-5cm inside the epidural space too shallow: increased risk inadequate anesthesia Too deep- may enter epidural vein or exit thru intervertebral foramen
What is the angle of a Tuohy needle?
30 degrees
How much LA is used with a supraclavicular block?
30 to 40cc of 1.5% lidocaine, .375-.5 of Bupivacaine or Ropivacaine
When properly placed, the ProSeal LMA allows a positive ventilation pressure of?
30cm H2O
The effect of hyperventilation on CBF lasts for ___ hours. -Why does it stop working?
6-20 hours -The pH of CSF equilibrates with PaCO2 *CO2 reactivity is usually preserved even in traumatized brains
Cobb angle with decreased pulmonary reserve
60
Cobb angle associated with decreased pulmonary reserve
60 degrees
Glucose content in CSF vs. plasma
60 in CSF vs. 90 in plasma
Oxygen utilization in the brain -Electrical activity -Cellular integrity
60% for electrical activity 40% for cellular integrity -Even if the brain is electrically silenced it still consumes O2 to support cellular integrity
Which disorder is common in patients with Eaton-Lambert syndrome?
60% have small-cell (oat-cell) carcinoma of the lung- consider this for patients with lung cancer that are undergoing mediastinoscopy. bronchoscopy, thoracoscopy
Maximum inflation pressure of the LMA classic?
60cm H2O
A patient received a citrated non-particulate antacid, but the case has been delayed. How long after the initial dose should a second dose be considered?
60minutes
pH of CSF
7.33 (PaCO2 47 in CSF)
What is a common mode of failure with interscalene blocks?
A common mode of failure in interscalene blocks of the brachial plexus under ultrasound guidance is injection into the body of the anterior or middle scalene muscle.
What causes a PDPH
A decrease in the amount of CSF in the subarachnoid space causing the medulla & brainstem to drop into the foramen magnum.
Normal Babinski Response
A firm stimulus to the underside of the foot produces a downward motion of all toes
Babinski sign with damage to the upper motor neurons in the corticospinal tract
A firm stimulus to the underside of the foot produces an upward extension of the big toe with fanning of the other toes
A high venous pressure increases/decreases cerebral venous drainage and increases/decreases cerebral volume. -Significance?
A high venous pressure decreases cerebral venous drainage and increases cerebral volume. -Creates backpressure to brain that reduces arterial/venous pressure gradient (MAP-CVP)
How does a *hyperbaric* solution distribute in the *sitting* patient?
A hyperbaric sol'n will settle to the lowest point of the spinal canal Keep pt sitting w/ hyperbaric = *sacral nerve roots* anesthetized (SADDLE BLOCK)
Chronic treatment of hydrocephalus
A shunt drains CSF to the peritoneal cavity (ventriculperitoneal shunt) or the right atrium (ventriculoatrial shunt)
What is a chylothorax?
A type of pleural effusion. It results from lymph formed in the digestive system called (chyle) accumulating in the pleural cavity due to either disruption or obstruction of the thoracic duct.
Which drugs may reduce CSF production?
Acetazolamine and furosemide
The *femoral n.* provides SENSORY innervation to ______________.
Anterior thigh
(2) true statements about EMLA cream?
Adequate anesthesia is obtained in 60minutes. It can cause methemoglobinemia 2.5% lidocaine 2.5% prilocaine
How do you differentiate between a cholinergic crisis and a myasthenic crisis? What is the test called?
Administer 1-2mg IV edrophonium - if weakness gets worse, it's cholinergic crisis. If there is improvement in muscle strength, myasthenic AKA the Tensilon test
Endocrine complications from RA
Adrenal insufficiency and infections d/t steroids
Endocrine complications of RA
Adrenal insufficiency and infections d/t steroids
Where does the dural sac end?
Adult: S2 - correlates with the superior iliac spines infant: S3 subarachnoid space terminates at the dural sac
The grey matter in the spinal cord is the processing center for which signals entering from where?
Afferent signals coming from the periphery
Anesthetic considerations involving use of volatile anesthetics in the obese population
Agents with lowest Blood: gas coefficients provide the fastest emergence. Less accumulation in the fat. MAC is unchanged by obesity
Complications of the prone position
Airway edema - leak test ETT mainstem or kink Cerebral hypoperfusion - neck rotation -> venous compression Ischemic optic neuropathy Corneal abrasion brachial plexus injury Ulnar n injury DVT (hip flexion -> femoral vein occlusion) Lateral femoral cutaneous n. injury (iliac crest pressure) peroneal n. injury (Lateral fibula pressure) ↑abdominal pressure
Scleroderma anesthetic considerations
Airway: limited mouth opening Respiratory: Pulmonary fibrosis & pulmonary HTN Heart: Dysrhythmias and CHF Blood vessels: decreased compliance -> HTN Kidneys: renal failure & renal artery stenosis -> HTN Peripheral & cranial nerves: nerve entrapment -> neuropathy eyes: dryness -> corneal abrasion
Sphenopalantine Ganglion block: Is the alternative to _____ Steps to preform 1-6:
Alternative to Blood patch 1. soak cotton tip applicator in LA (1-2% lido or 0.5% bupi) 2. place pt in sniffing position 3. insert applicator into each nare towards middle turbinate 4. Insert until posterior wall of nasopharynx is reached- this is where the sphenopalantine ganglion are 5. leave applicator there for 5-10min 6. pt should notice symptom improvement
Clonidine 1mcg/kg provides what?
Analgesia that is equal to opioid analgesia
Techniques For Peripheral Nerve Blocks
Anatomic Localization Field Block Elicitation of Paresthesia (Blunt) Perivascular Sheath (Sheath pop) Transarterial placement Nerve Stimulator ( 1mA highly specific .5mA nearly 100% successful) Ultrasound
Median Nerve wrist block
Anatomic landmarks: flexor carpi radial tendon & flexor palmaris longus tendon Inject 5mL between the flexor carpi radial tendon and the flexor palmaris longus tendon
Radial Nerve wrist block
Anatomic landmarks: radial styloid Subq injection = 10mL proximal to the radial styloid (field block)
Ulnar Nerve wrist block
Anatomic landmarks: ulnar styloid, ulnar pulse, flexor carpi ulnaris tendon Inject 3-5mL medial to and below the flexor carpi ulnaris tendon
Most common hematologic complication of RA?
Anemia Platelet dysfunction is d/t NSAID use
Hematologic complications of RA
Anemia Platelet dysfunction secondary to NSAIDs
What might you see once interscalene block achieved?
Anesthesia is then evaluated in 5 min. Weakness of biceps or sensory anesthesia of forearm. Horners Syndrome SOB
popliteal nerve block anesthetizes all of the these 3 nerves ___ but not ____
Anesthetizes the sciatic nerve and its branches(common peroneal and tibial) Saphenous nerve is a branch of the femoral nerve. It is not blocked by a popliteal nerve block
Most common cause of subarachnoid bleeding
Aneurysm rupture
Order the 5 ligaments of the spinal column from posterior to anterior
Answer next page
What do MEPs test?
Anterior cord Anterior spinal artery Motor function - NO NMB's
Effect of maternal MG on the neonate
Anti-AchR IgG antibodies cross the placenta and cause weakness in 15-20% of neonates that may persist for 2-4 weeks (consistent wit the 1/2 life of Anti-AchR IgG antibodies in the neo's circulation) *those neonates may require airway management when born
Treatment of MG
Anticholinesterases- pyridostigmine Immunosuppression-corticosteroids,cyclosporin, azathioprine, mycophenolate Thymectomy- (approach via median sternotomy or transcervical) Plasmapheresis- temporary relief during MG crisis or prior to thymectomy
First line treatment of MG
Anticholinesterases: Oral pyridostigmine
Which drugs should be avoided in a patient with Parkinson's?
Antidopaminergics (metoclopramide, butyrophenones like haldol/droperidol, phenothiazines) Alfentanil Possibly ketamine (controversial) *exacerbate extrapyramidal sx
Hematologic complications of SLE
Antiphospholipid antibodies Hypercoagulability Anemia Thrombocytopenia Leukopenia
Use of bupivicaine, levobupivicaine, ropivicaine in pediatrics
Any concentration is ok as long as dose does not exceed 2.5mg/kg
Unacceptable response to twitch monitor (axillary)
Anything else
Anterior spinal artery circulation
Aorta - subclavian - vertebral - anterior spinal Aorta - segmental - anterior radicular - anterior spinal
Anterior cerebral circulation
Aorta -> Carotid artery -> Internal carotid artery -> Circle of Willis -> Cerebral hemispheres enter the skul through the foramen lacerum
Guillain-Barre S/S
Ascending muscle weakness up to face (distal to proximal) Intercostal muscle weakness (may need mechanical ventilation) Facial and pharyngeal weakness -> aspiration risk Sensory deficits: paresthesias, numbness, &/or pain ANS dysfxn: tachy or brady-cardia, HTN or HoTN, diaphoresis or anhidrosis, orthostatic HoTN
Risks to consider w/ Myotonic dystrophy
Aspiration Respiratory muscle weakness cardiomyopathy & dysrhythmias Sensitive to anesthetic agents (No increased risk for MH)
If tPA can't be administered for an ischemic stroke, what may be given as an alternative?
Aspirin
Which type of glial cell is most abundant?
Astrocytes
Where do the two venous pathways of the brain converge?
At the confluence of sinuses
Most common site of transtentorial herniation
At the temporal uncus -As ICP rises, the temporal uncus is forced from the supratentorial space into the infratentorial space which increases pressure on the midbrain
Metabolites of which drugs may produce seizure activity?
Atracurium (laudanosine) and meperidine (normeperidine) *cisatracurim also produces laundanosine, but much smaller quantities
NMB that can be implicated in seizures
Atracurium d/t laudanosine production - mostly caused by long term infusions Laudanosine is also a metabolite of Cis, but it is produced in much smaller quantities.
Anesthetic considerations for hyperkalemic periodic paralysis What not to administer? What is okay to administer?
Avoid succinylcholine and potassium-containing solutions (LR) Okay: Glucose containing fluids, K+waste diuretics, B2 agonists, NDNMB, Acetazolamide
For DBS the patient needs to be:
Awake or lightly sedated can lightly sedate with opioids or precedex
what will you see in a block/lesion to the axillary nerve ?
Axillary (C 5,6 ) Difficult abducting arm to horizontal - Deltoid. Sensory deficit- Lateral side of arm below point of shoulder *"inability to abduct arm"* [can be injured from arm hanging off OR table]
Axillary nerve
Axillary nerve is derived from the posterior cord. Motor innervation is deltoid and theres minor muscles that act on the shoulder joint. Sensory innervation is from the skin just below the point of the shoulder. [Shoulder drop]
Which vertebrae does the *coccygeal plexus* arise from?
S4 - Co
Neuraxial recommendations w/ warfarin
B/f block hold 5d catheter can be removed when INR < 1.5
Factors that don't affect spread of spinal anesthesia
Barbotage Increased intra-abdominal pressure Speed of injection Orientation of bevel Addition of vasoconstrictor Weight Gender
steal phenomenon
Blood vessels that supply ischemic or atherosclerotic regions are maximally dilated. Therefore anything that causes cerebral vasodilation (↑PaCO2/vasodilators) can decrease the blood supply to these ischemic tissues as some of it is diverted to newly dilated vessels
Detail the dosing and drugs commonly used for a continuous *femoral n.* block
Bolus + 8-10mL/hr 0.2% Ropivicaine or 0.25% Bupivicaine
Axillary block level
Branches
How does the brain compensate for increased volume of CSF or blood?
CSF is shunted to the spinal canal -horizontal portion of ICP curve -As intracranial volume rises, CSF cannot compensate and CPP suffers
The posterior branch of the *femoral n.* gives rise to the ________________ nerve.
SAPHENOUS (nerve)
CSF volume and specific gravity
CSF volume: ~150mL CSF specific gravity: 1.002 - 1.009 produced by ependymal cells at rate of 30mL/h
Contents of the subarachnoid space
CSF, nerve roots, rootlets, spinal cord (spinal cord is covered by the pia mater)
Channel dysfxn associated w/ Hypokalemic periodic paralysis
Ca+ channelopathy
Where is the superior trunk located?
C5-C6
Most common site of spinal cord injury
C7
When the action potential depolarizes the nerve terminal what is limited?
Ca+ entry into the presynaptic terminal which reduces the amount of Ach mobilized and released in synaptic cleft
Method of treating hyperkalemia with MH
CaCl 5-10mg/kg Insulin 0.15 U/kg and D50 1mL/kg Hyperventilation
Arterial Oxygen Content
CaO2= (SaO2 x Hb x 1.34) + (PaO2 x 0.003)
What medication class should never be given with MH
Calcium channel blocker - can precipitate Hyperkalemic cardiac arrest when given with Dantrolene
Dexmedetomidine (2 reactions)
Can cause HTN(central A2 stimulation causes vasodilation, sedation, and analgesia. Peripheral stimulation initiates vasoconstriction) reduces adenylate cyclase(stimulation of G protein inhibits adenylate cyclase and reduces cAMP)
Inhaled anesthetic effect on seizures
Can cause seizures but usually EEG activity is suppressed in a dose dependent fashion
Adductor Canal block
Can provide analgesia for knee surgery w/o affecting quadriceps function- pts can ambulate sooner after surgery
What areas of the brain are not protected by the BBB
Chemo trigger zone, posterior pituitary gland, pineal gland, choroid plexus, part of hypothalmus
Where is the BBB not present? (CCPPP)
Chemoreceptor trigger zone (CTZ) Choroid plexus Posterior pituitary gland Pineal gland Parts of the hypothalamus
An overdose of anticholinesterases in myesthenia gravis can cause:
Cholinergic crisis and muscle weakness (cholinergic crisis can be difficult to differentiate from myasthenic crisis)
Ketorolac should be avoided in all except: (samters triad, PUD, renal insufficiency, chroncic bronchitis)
Chronic bronchitis
The anterior and posterior circulations converge at the:
Circle of Willis
Differential block
Clinical phenomenon that nerve fibers with different functions have different sensitivities to local anesthetic blockade
What can be reversed with platelet transfusion?
Clopidogrel or aspirin Also some evidence of reversal with recombinant factor VIIa
Neuraxial recommendations w/ Thienopyrodine derivatives
Clopidogrel: b/f block placement hold 7 days Ticlodipine: b/f block placement hold 14 days
What is the one contraindication to a *psoas compartment* block?
Coagulopathy
Which angle describes the magnitude of the spinal curvature?
Cobb
Cerebral cortex functions
Cognition, sensation, movement -Structure of the cerebral hemisphere
Sacral hiatus
Coincides w/ S5 -covered by the sacrococcygeal ligament -provides entry point to the epidural space
Methods to cool the patient
Cold IVF Cold fluid lavage of stomach and bladder Ice packs
Which two nerves converge in the *sacral plexus* to make the *sural nerve*?
Common peroneal n. + Tibial n.
Which two nerves converge in the *sacral plexus* to make the *sural nerve*?
Common peroneal n. + Tibial n.
*Sacral Plexus* In the Ankle
Common peroneal n. gives rise to: - Superficial peroneal n. - Sural n. Deep peroneal n. Tibial n. gives rise to: - Posterior tibial n - Sural n.
*Sacral Plexus* In the Ankle
Common peroneal n. gives rise to: - Superficial peroneal n. -Deep peroneal n. - Sural n. Tibial n. gives rise to: - Posterior tibial n. - Sural n.
Plica mediana dorsalis
Connective tissue between ligamentum flavum and dura mater (in epidural space) - theoretical - considered to be a cause for difficult epidural cannulation and unilateral blocks
Marfan syndrome definition
Connective tissue disorder with autosomal dominant inheritance (aortic insufficiency and AAA) *Minimize wall stress with BB
Osteogenesis imperfecta definition
Connective tissue disorder with autosomal dominant inheritance, resulting in weak bones
White matter contains what? What is it divided into?
Contains the axons of the ascending and descending tracts Divided into dorsal, lateral, and ventral columns
What is the function of Merkel's discs?
Continuous touch
Stroke Diagnosis
Contrast CT - if bleeding is ruled out by CT, ischemic stroke is assumed & TPA can be given. ASA is an alternative if TPA cannot be given
Corticospinal tract travels from where to where and what type of pathway is it?
Cortex to spine Motor pathway
Most important motor pathway
Corticospinal tract
SLE treatment
Corticosteriods NSAIDs Immunosppressents Antimalarials
Symptoms of myasthenia gravis
Diplopia, ptosis Bulbar muscle weakness (muscles of mouth and throat) Dysphagia, dysarthria, difficulty handling saliva Dyspnea with exertion Proximal muscle weakness
DMD association w/ MH
DMD is associated w/ MH-like syndrome Its really rhabdomyolysis - any cardiac arrest on induction of a DMD pt should be considered to have severe hyperkalemia. Dantrolene does not treat this d/o. They have a normal ryanodine receptor. Succ and volatile anesthetics can trigger this syndrome.
Inside the femoral triangle, the femoral n. runs _________________ to the inguinal ligament.
DEEP
Carbidopa
Decarboxylase inhibitor Prevents levodopa metabolism in the blood, so more levodopa can enter the CNS
Epidural blood patch
Definitive treatment 90% success rate 10 to 20 mls of sterile venous blood Side effects: back ache and radicular pain
Cardiac changes in Duchenne
Degeneration of cardiac muscle (reduces contractility, papillary muscle dysfunction, causes MR, cardiomyopathy, and CHF) Signs of cardiomyopathy: Resting tachy, JVD, S3/S4, displacement of the point of maximal impulse *gold standard cardiac eval is echo
*Hydrophilic* Opioids: Onset
Delayed (30 - 60 min) *meperidine, hydromorphone, morphine
Eaton-Lambert syndrome
Disorder of the NMJ that results in skeletal muscle weakness d/t destruction of the presynaptic voltage-gated calcium channel, reducing the amount of ACh that is released into the synaptic cleft
Area where the nerve stimulator should be placed to elicit contraction of the adductor pollicis muscle?
Distal electrode is placed over the proximal flexor crease of the wrist and the proximal electrode is placed over the flexor carpi tendon.
Most sensitive indicator of MH
EtCO2 rise (out of proportion to minute ventilation)
Most sensitive indicator of MH
ETCO2 that rises out of proportion to minute ventilation
Reconstitution of Dantrolene
Each vial contains 20mg of Dantrolene + 3g Mannitol reconstituted w/ 60mL sterile water (Do not use normal saline, it takes longer to dissolve)
*Hydrophilic* Opioids: Respiratory depression
Early ( < 6 hrs) Late ( > 6 hrs)
Factors that DO NOT increase the risk of TNS
Early ambulation, LA concentration, baricity, glucose concentration
*Lipophilic* Opioids: Respiratory depression
Early only
Hydrophilic opioids respiratory depression
Early: less than six hours Late: 6 to 12 hours
Side by side compare Eaton-Lambert to Myasthenia Gravis
Eaton Lambert: Ca+Channel effected- presynaptic Decreased Ach release Presynaptic neuron Small-cell lung carcinoma (oat cell) Sensitive to Nodepolarizers and Succs AchE inhibitors are not effective Myasthenia Gravis: Postsynaptic Nm receptors effected Decreased response to Ach Postsynaptic motor endplate is effected Thyoma Sensitive to Nondepolarizers Resistant to Succs AchE inhibitors adequate
An epidural hematoma should be evacuated within
Eight hours
Percentages of oxygen utilization in the brain
Electrical activity = 60% Cellular integrity = 40%
Antidromic AVNRT(widened QRS) results when
Electrical impulse travels via the accessory pathway
Filum Terminale
Extends conus medullaris to coccyx
filum terminale
Extends from the conus medullaris to the coccyx
Radial nerve movement
Extension at elbow Supination of forearm Extension of wrist and fingers
What is the most common cause of central retinal artery occlusion?
External compression on the globe from improper head positioning in prone position- reduces venous outflow, increases intraocular pressure, impedes retinal perfusion
Absence of dystrophin allows for: What does the above predispose patients to when given succinylcholine?
Extrajunctional receptors to populate the sarcolemma Hyperkalemia (succs does have the BB warning of sudden cardiac arrest/death in kids with undiagnosed Skmuscle myopathy)
What are all other motor pathways outside of the corticospinal tract known collectively as?
Extrapyramidal tract - these fibers do not pass through the pyramids
Components of GCS
Eye opening (1-4) Motor response (1-6) Verbal response (1-5)
T/F: adding lidocaine jelly to the cystoscope or Foley catheter will prevent autonomic hyperreflexia
FALSE
Warfarin can be reversed with...
FFP, Prothrombin Complex Concentrate, or recombinant factor VIIa
Cranial Nerve VII -Nerve name (5 branches) -Function -Bedside test
Facial (temporal, zygomatic, buccal, mandibular, cervical) Both Facial movement Eyelid closing Taste anterior 2/3 of tongue *Two zebras bit my carrot *Two zits by my clavicle
What are (2) appropriate treatments for a patient with von willebrands disease?
Factor 8 concentrate Desmopressin
Factors that increase the risk of MH
Families from Wisconsin, Nebraska, West Virginia, and Michigan Male Youth
All are associated with apoptosis in the developing brain except (ketamine, fentanyl, midazolam, sevoflurane)
Fentanyl
Select (2) best agents for the neonate with necrotizing enterocolitis
Fentanyl Ketamine Better options than VA and propofol
Preparations for MH patient
Flush machine w/ high flow O2: 20-100min Replace all external components: circuit, CO2 absorbent, breathing bag Remove vaporizers Monitor in PACU for 1-4 hours
What are better headrest options to avoid central retinal artery occlusion?
Foam pillow with cut outs around eyes or mayfield pins
Boundaries of the epidural space
Foramen magnum Sacralcoccygeal ligament Posterior longitudinal ligament vertebral pedicles Ligamentum flavum Vertebral lamina
The Dura matter begins and ends at:
Foramen magnum dural sac
Oligodendrocytes function
Form the myelin sheath in the CNS
C8 sensory innervation
Fourth and fifth digits
Factors that increase the risk of MH
Geography (Wisconsin, Nebraska, West Virginia & Michigan) Male Youth
When is ICP monitoring indicated?
Glasgow coma score </= 7
Global, Cortical and Subcortical cerebral blood flows
Global: 45-55mL/100g tissue/min Cortical: 75-80mL/100g tissue/min Subcortical: 20mL/100g/tissue/min
Cranial Nerve IX -Nerve name -Function -Bedside test
Glossopharyngeal Both Somatic sensation and taste to posterior 1/3 tongue
Meds to avoid w/ hypokalemic periodic paralysis
Glucose containing solutions Potassium wasting diuretics Beta-2 agonist
Meds that are safe w/ hyperkalemic periodic paralysis
Glucose containing solutions Potassium wasting diuretics Beta-2 agonist NDNMB's Acetazolamide
During cerebral hypoxia _______ is converted to lactic acid.
Glucose converts to lactic acid- cerebral acidosis destroys brain tissue. *This is why you dont want hyperglycemia
Risk factors for a CVA
HTN (most important) Smoking, DM, HLD, excessive alcohol, elevated homocysteine level (amino acid from meat)
BP during stroke
HTN is common after ischemic stroke Hypotension decreases CPP and worsen ischemia target pressure should maintained under 185/110
clearance is inversely proportional to (2)
Half-life concentration in the central compartment
It is possible for _____ and ____ to initiate MH like syndrome in the patient with duchenne muscular dystrophy.
Halogenated agents and succs- so avoid them in DMD
What are the only 2 classes of drugs that trigger MH?
Halogenated anesthetics and Succs
Which agents increase beta amyloid production?
Halothane and isoflurane
What is the definitive test for MH
Halothane contracture test
Definitive test for diagnosis of MH
Halothane contracture test high sensitivity and low specificity
Dantrolene MOA
Halts Ca+ release from the RyR1 receptor Prevents Ca+ entry into the myocyte
S/sx of intracranial hypertension
Headache N/V Papilledema - optic nerve swelling Focal neurologic deficit Decreased LOC Seizure Coma
Are the nerves for the infraclavicular block hyper or hypoechoic
Hyperechoic (they are hypoechoic for scalene and supraclavicular)
cranial nerves
I. Olfactory II. Optic III. Oculomotor IV. Trochlear V. Trigeminal VI. Abducens VII. Facial VIII. Vestibulocochlear IX. Glossopharyngeal X. Vagus XI. Accessory XII. Hypoglossal
What increases as a result of pneumoperitoneum during laparoscopic surgery (3)
ICP+CPP A-a gradient - as a function of decreased FRC and V/Q mismatch MAP- due to hypercarbia, the neuroendocrine respone(catecholamines, vasopressin, cortisol) and increased afterload
Parasympathetic output is carried by which cranial nerves?
III, VII, IX, and X
Respiratory affects of Neuraxial anesthesia
Impairment of intercostal muscles (inspiration & expiration) Impaired abdominal muscles (cough, clear secretions) Reduced accessory muscle function Loss of proprioception input from the chest can cause dyspnea Apnea is usually the cause of cerebral hypoperfusion NOT phrenic nerve paralysis
Where do pain neurons synapse?
In the substantia gelatinosa in laminae II and III
Prep options to clean back? Most effective? Caution with:
Iodine, alcohol, chlorhexadine Most effective- alcohol with chlorhexdine Caution: Chlorhexidine is neurotoxic- needs to dry before puncturing skin
First order neurons of the dorsal column ascend the spinal cord on which side?
Ipsilateral - the same side that it entered
Which type of CVA is most common?
Ischemic
Most common cause of vision loss in the perioperative period
Ischemic optic neuropathy
Relative tonicity of CSF compared to plasma
Isotonic (CSF is isotonic with plasma, it is not an ultrafiltrate of plasma and has its own chemical composition) -Osmolarity the same 295 mOsm/L
How does metabolic acidosis effect CBF
It has no effect because H+ cannot pass BBB (only CO2), so respiratory acidosis increases CBF
Conditions that impair venous drainage
Jugular compression secondary to improper head positioning Increased intrathoracic pressure secondary to coughing or PEEP Vena cava thrombosis Vena cava syndrome
At what point does the *femoral n.* divide into anterior and posterior branches?
Just after it passes under the inguinal ligament
Where do the roots turn into trunks?
Just beyond the *lateral border* of the *scalene muscles*
Which IV agent should be avoided in a patient with a history of seizures?
Ketamine
IV agents to avoid in patient w/ history of seizures
Ketamine* (most important) Etomidate, Methohexital, Alfentanil increase EEG activity and can be used for cortical mapping Propofol has been implicated in seizures but it is still a first line drug for seizure activity
ADULT Conus Medullaris
L1 - L2
Area of myocardium most susceptible to myocardial ischemia
LV subendocardium
The dorsal column contains what kind of fibers?
Large, myelinated, rapidly conducting fibers
Scoliosis Definition -Kyphoscoliosis Definition
Lateral and rotational curvature of the spine and ribcage -Posterior curvature of the spinal column
Most common causes of acute spinal cord injury
MVC, fall, assault, sports injury.
Archeocerebellum function
Maintains equilibrium -Structure of cerebellum "architecture needs equilibrium"
Patient risk factors for ION
Male, obese, diabetes, HTN, smoking, old age, atherosclerosis
What is the recommended mA of nerve stimulation?
Many authors recommend a current of 0.2-0.5 mA as an end goal.
PaCO2 levels at which maximal vasodilation and vasoconstriction occur
Maximal vasodilation -> PaCO2 80-100mmHg Maximal vasoconstriction -> PaCO2 25mmHg
Changes in anesthetic management for a patient with Parkinson's undergoing deep brain stimulation
May want to hold levodopa, which worsens symptoms and facilitates optimal electrode placement
The Dorsal column medial leminiscal system transmits what?
Mechanoreceptive sensations: fine touch, proprioception, vibration, fine pressure
A Delta peripheral nerve fibers
Media myelination Function: fast pain, touch, temperature Diameter: 2 to 5 µm Velocity: Sub medium Block onset: Third
This cord gives off a branch of the median nerve and ends as the ulnar
Medial cord
Which column transmits sensory information faster: dorsal medial lemniscal or anterolateral (spinothalamic tract)?
Medial lemniscal (dorsal)
Which opioid can cause seizures
Meperidine d/t its metabolite normeperidine
Where do third order neurons of the anterolateral system synapse? -Tactile signals -Pain fibers
Most tactile signals are relayed to the ventrobasal complex of the thalamus Fibers pass through internal capsule and advance toward somatosensory cortex in the post central gyrus in the parietal lobe -Pain fibers synapse in the RAS--> connections to the thalamus
Anterior nerve root carry:
Motor and autonomic function
Normal muscle coordination neural pathway
Motor cortex sends impulse to basal ganglia and cerebellum Basal ganglia and cerebellum send info to cortex by way of thalamus this feedback loop dependent on relative concentrations of dopamine and ach
Musculocutaneous innervation
Motor of arm Sensory of lateral forearm and wrist
The *femoral n.* MOTOR innervation Anterior and Posterior Sensory innervation
Motor: Anterior branch - sartorius Posterior branch - quads Sensory: Anterior thigh
Most of the CNS neurons are what type?
Multipolar
What are the 3 types of neurons found in the CNS?
Multipolar Pseudounipolar Bipolar
What is dantrolene classified as? Most common side effects of dantrolene
Muscle relaxant Muscle weakness and venous irritation
TNS treatment
NSAIDs opioids trigger point injections
What do you see on the out of plane approach?
Needle is at best seen only in cross section. More commonly, tissue movement is seen as the needle approaches the target.. [If you're going towards the probe perpendicularly, it's OUT of plane, if you're going Parallel to the probe, it's IN PLANE. This is JUST for needle insertion]
What ligaments are penetrated with the paramedian approach to the epidural space?
Needle will pass through 1 ligament: Ligamentum flavum
What ligaments are penetrated with the midline approach to the epidural space?
Needle will pass through 3 ligaments: Supraspinous Interspinous Ligamentum flavum
Renal complications of SLE
Nephritis w/ proteinuria
Renal complications of SLE
Nephritis with proteinuria
What does NAVEL stand for?
Nerve, Artery, Vein, empty space, Lymphatics. Nerves are ALWAYS the most lateral!!!
Axillary approach?
Nerves anesthetized around axillary artery where they have regrouped into terminal branches Straddle the pulse between your two fingers; go above artery; insert 1-2cm
T4 sensory innervation
Nipple line
Cranial Nerves
Oh, Oh, Oh, To, Touch, And, Feel, A, Girls, Vagina, Ah Heaven A - auditory vestibular nerve
Factors w/ lower risk of PDPH
Older age Male Non-cutting tip needle Smaller diameter needle Fluid for LOR syringe Needle parallel to long axis of meninges Continuous spinal catheter (if placed after wet tap)
Cranial Nerve I -Nerve name -Function -Bedside test
Olfactory Sensory Smell
Cranial Nerve Pneumonic
On Old Olympus Towering Top, A Fin and German Viewed A Hopp
HIGHER Risk Factors for PDPH
Patient Factors - young - pregnant - female Provider Factors - cutting-point tip needle - big diameter needle - multiple dural punctures - using air for Loss of resistance - needle perpendic to long axis of meninges
Absolute contraindication to neuraxial anesthesia
Patient refusal
When performing an epidural blood patch, how do you know when it is working?
Patient senses pressure in legs, buttocks, or back
Describe the managment of gout (2)
Patients should be liberally hydrate Sodium bicarb enhances uric acid excretion
Unacceptable response to twitch monitor (supraclavicular)
Pectoralis Bicep Deltoid
Unacceptable response to twitch monitor (infraclavicular)
Pectoralis Biceps Deltoid
Non-cutting tip
Pencil tip point: Sprotte, Whitacre, Pencan Rounded bevel tip: Greene
Complications of supraclavicular
Pneumothorax happens most frequently with this approach to brachial plexus blockade Hemothorax Horner's syndrome Phrenic nerve blockade Recurrent Laryngeal block Contraindicated in patients with severe pulmonary disease.
Most common SLE problems
Polyarthritis and dermatitis
Label the brain
Pons Medulla oblongata Midbrain Temporal lobe Hypothalamus Spinal cord Cerebellum Occipital lobe Parietal lobe Parietooccipital sulcus Frontal lobe Central sulcus Thalamus Corpus callosum Lateral ventricle
What, in the brainstem, causes autonomic integration?
Pons and medulla
The *saphenous n.* block is useful when combined with waht other 2 blocks?
Popliteal block or Ankle block (these do not capture the saphenous n. distribution)
The *saphenous n.* block is useful when combined with what other 2 blocks?
Popliteal block or Ankle block (these do not capture the saphenous n. distribution)
Situations that exacerbate MG symptoms
Pregnancy infection electrolyte abnormalities stress aminoglycoside antibiotics (-mycins*gentamycin, neomycin)
Situations that exacerbate myasthenia gravis
Pregnancy Infx Electrolyte abnormalities Surgical & pyschological stress Aminoglycoside abx
Risk factors with difficult mask ventilation (4)
Presence of a beard BMI >26 lack of teeth history of snoring
*Sacral Plexus* Primary Nerves
Post. femoral cut. n. Sciatic n.
The dorsal column is perfused by which blood supply?
Posterior blood supply (touch and proprioception are spared)
This cord gives off the axillary nerve and ends as the radial
Posterior cord
What do SSEP's test?
Posterior cord Posterior spinal arteries Sensory function *does not monitor motor function
Anterior border of the epidural space
Posterior longitudinal ligament
The *posterior femoral cutaneous n.* provides SENSORY innervation to ___________.
Posterior thigh
Where is the *sural n.* blocked?
Posterior to the lateral malleolus
Where is the *posterior tibial n.* blocked?
Posterior to the medial malleolus
Where is the *posterior tibial n.* blocked?
Posterior to the medial malleolus (bump on medial ankle)
Ventral corticospinal tract is responsible for:
Posture motor
How should you dose nondepolarizers in a patient with MG?
Potency is increased (increased sensitivity) Reduce dose by 1/2 to 2/3
Levodopa
Precursor to dopamine Metabolized to dopamine in circulation - does not penetrate the CNS
Factors that can cause SLE exacerbation
Pregnancy Stress Infection Surgery
While propofol is a first line tx for seizure control, it can rarely cause:
Propofol induced seizures and opisthotonos (rigid posture with arched back)
Acute treatment of a grand mal seizure: Surgical treatment:
Propofol, diazepam, thiopental Surgical: Vagal nerve stimulator/ resection of foci
What is the function of Ruffini's endings?
Proprioception and prolonged touch and pressure
Astrocytes
Provide structural and metabolic support for neurons. Most abundant type of cell in CNS Repair neurons after injury
What is the primary function of Circle of Willis?
Provides redundancy of blood flow in brain.
Which cuff do you inflate first for bier block?
Proximal
Which muscles are most affected in Eaton-Lambert syndrome?
Proximal
With an open repair of an aneurysm, where is the clamp placed and why?
Proximal feeder vessel- placed there to reduce transmural pressure/ risk of rupture while eliminating the need for controlled hypotension *some surgeons don't use clamps may request controlled hypotension- most significant risk is decreased CPP
What is the most common side effects of neuraxial opioids
Pruritus More common in OB patients Stimulation of opiate receptors in the trigeminal nucleus Treat with naloxone
Which lower extremity nerve block has the highest rate of complications?
Psoas compartment block
Brachial plexus - medial to lateral
Randy Travis Drinks Cold Beer Roots Trunks Divisions Cords Branches
Site of absorption of CSF
Reabsorbed into venous circulation via arachnoid villi in the superior sagittal sinus
If a patient requires >20mg/kg of dantrolene:
Reconsider the dx of MH
All inhalational agents are capable of producing seizures, however they they tend to reduce _____ activity in a __________
Reduce EEG activity in a dose dependent way.
Alzheimer's pathophysiology
Reduced ACh, Beta Amyloid Plaques, Neurofibrillary Tangles These cause: Dysfunctional synaptic transmission & Apoptosis Degeneration of Neurons: Early hippocampus/memory; Late cerebral cortex/speech/reasoning
Diagnosis of Parkinson's requires 2 of the 4 cardinal signs:
Resting "pill rolling" tremor Skeletal muscle rigidity Postural instability - loss of balance with altered gait Bradykinesia - slow movement and reflexes
Early respiratory complication of scoliosis
Restrictive ventilatory defect -↓FEV1 & FRC -normal FEV1/FVC ratio Decreased lung volumes: VC, TLC, RV, FRC Decreased chest wall compliance
Pulmonary complications of SLE
Restrictive ventilatory defect Pulmonary hypertension Interstitial lung disease w/ impaired diffusing capacity Pleural effusion Recurrent pulmonary emboli
Where are bipolar neurons found?
Retina and ear You have 2 eyes and 2 ears
Anesthetic considerations for Eaton-Lambert syndrome
Reversal with anticholinesterases may be inadequate even with proper dosing High risk for postop ventilatory failure
Laboratory findings w/ RA
Rheumatoid factor ↑C-reactive protein ↑erythrocyte sedimentation rate
What is the only drug that reduces mortality with ALS?
Riluzole, an NMDA receptor antagonist
interscalene block level
Root level
Which level is the interscalene block?
Root level- most proximal of the brachial plexus
What are the 5 main components of the brachial plexus? The roots arise from C___ to T____
Roots = 5 Trunks = 3 Divisions = 6 Cords = 3 Branches = 5 Reach To Drink Cold Beer *roots arise from C5-T1
In a male patient, what is the next step after the tip of the double lumen ETT passes through the vocal cords?
Rotate the DLT 90 degrees in the direction of the bronchus to be intubated
*Lipophilic* Opioids: How long do they stay in CSF?
SHORTER period of time vs. hydrophilic
Neuraxial recommendations w/ unfractionated heparin
SQ: Proceed w/ block if pt is not on any other blood thinners and has normal clotting mechanisms IV: b/f block hold for 2-4 h after block hold for 1h b/f catheter removal hold for 2-4h
Sacral Hiatus -Coincides with __ -Results from... -Covered by ___ ligament -Significance
Sacral Hiatus -Coincides with S5 -Results from incomplete fusion of the laminae at S5 and sometimes S4 -Covered by sacrococcygeal ligament (punctured with caudal approach) -Provides entry point to the epidural space
*Pediatric* caudal anesthetic doses: (mL/kg)
Sacral: 0.5 mL/kg Sacral-low thoracic (T10) - 1mL/kg Sacral-mid thoracic - 1.25mL/kg
Caudal dosing Pediatric
Sacral: 0.5 mL/kilograms Sacral to low thoracic T10: 1 ML/kilogram Don't Exceed 2.5 mg per kilogram Of bupivacaine, levobupivacaine, Ropivacaine
*Adult* caudal anesthetic doses: (mL)
Sacral: 12 - 15mL Sacral-low thoracic (T10): 20 - 30mL Sacral-mid thoracic: N/A
Caudal dosing adult
Sacral: 12 to 15 ML's Sacral to low thoracic T10: 20 to 30 ML's
Caudal border of the epidural space
Sacrococcygeal ligament
*Lumbar Plexus* At the Ankle
Saphenous n.
Physiologic changes that are MOST likely to occur during autonomic hyperreflexia (2)
Seizures Pulmonary edema (acute rise in SVR can precipitate LV failure, and cause pulmonary edema) HTN bradycardia
Abrupt withdrawal of GABA can cause:
Seizures if pt has hx of seizures - taper for at least 1 week
myastehnia gravis: _______________ to Roc/Vec
Sensitive b/c there is reduced Ach nicotinic receptors at the NMJ -reduce dose by 1/3-2/3
Anesthetic mgmt Eaton-Lambert Syndrome
Sensitive to Succ and NDNMBs - reduce doses Volatile anesthetics are usually enough w/out NMBs Reversal w/ anticholinesterases may be inadequate despite proper dosing High risk for postop respiratory failure strong correlation to small cell carcinoma (oat cell carcinoma)
Effect of Eaton-Lambert syndrome on NMBDs
Sensitive to both succinylcholine AND nondepolarizers *REDUCE doses EL↓S
Patients with MG will be sensitive to ________ and resistant to _________
Sensitive to nondepolarizers and resistant to succinylcholine (d/t reduced type-m nicotinic receptors at NMJ)
Posterior nerve root carry:
Sensor information
T4 innervation
Sensory: nipple line Moto/Autonomic: T1-T4 cardiac accelerator fibers
What is the function of the BBB
Separates the CSF from the plasma -via tight junctions -does not have carrier proteins -poorly developed in neonates
What lab value is increased in patients with osteogenesis imperfecta?
Serum thyroxine (in >50% of patients) *Increased BMR and VO2 -> hyperthermia *Risk for MH is NOT increased
Type of fibers in the anterolateral system
Smaller, myelinated, slower conducting fibers compared to the dorsal medial leminiscal
Which electrolytes are similar between CSF and plasma?
Sodium Bicarb Chloride (119 in CSF vs 102 in plasma) PaCO2 (47 in CSF vs 40)
Method of correcting lactic acidosis with MH
Sodium bicarb 1-2mEq/kg
Which part of the neuron integrates the signal and has the cellular machinery?
Soma
What are the functions of each cranial nerve?
Some Say Marry Money But My Brother Says Big Brains Matter Most Sensory, Motor, Both
What kind of paralysis results from injury to an upper motor neuron? Why?
Spastic and hyperreflexia -Inhibitory impulses from the brain are blocked at the level of the injury which causes over activity of lower motor neurons
What is the plica mediana dorsalis? What is its significance?
Speculative band of connective tissue between ligamentum flavum + dura mater If it exists, it could create barrier impacting spread of meds w/in epidural space Potential culprit of difficult epidural insertion + unilateral EPD blocks *it's very existence is controversial
Absolute contraindications to caudal anesthesia
Spina bifida Meningomyelocele of the sacrum Meningitis
Cranial Nerve XI -Nerve name -Function -Bedside test
Spinal accessory Motor Shoulder shrug
conus medullaris
Spinal cord and at L1-L2 in adults L3 In infants
How does spinal anesthesia cause drowsiness?
Spinal reduces sensory input to the reticular activating system which can cause drowsiness
Most common cause of ION
Spinal surgery in the prone position can also occur after radical neck dissection or CPB
ION is most common after what type of surgery?
Spine surgery in the prone position can also occur after CPB and radical neck dissection
Spinothalmic tract travels from where to where and what type of pathway?
Spine to thalamus Sensory
Tract of Lissauer is part of the:
Spinothalamic tract (anterolateral)
Pencil point tip Needles
Sprotte Whitacre Pencan Pros: -lower risk of post dural puncture headache -More tactile feel -Needlee likely to deflect -Less likely to injure cauda equina Cons: requires more force
*Interscalene block* Landmarks Image
Sternocleidomastoid muscle- accentuate by having pt lift head
Meningismus
Stiff neck Sign of meningitis Occurs as blood spreads throughout and irritates the subarachnoid space
What is the goal of spinal fusion with instrumentation for scoliosis patients?
Stop the progression of the curvature and prevent further deterioration of cardiopulmonary function
Lipophilic opioids
Sufentanil Fentanyl Substantial gelatinosa Rexed lamina II & III Fast onset,short duration More systemic absorption Early respiratory depression Lower incidence of nausea vomiting pruritus
At the level of the ankle, which nerve is not immediately adjacent to a vascular structure?
Superficial peroneal nerve *LEAST likely to result in intravascular injection
Bier block technique
Supine position Place double cuff proximal, IV distal Elevate extremity and exsanguinate with esmarch bandage Inflate proximal tourniquet Inject LA 40 to 50cc of .5% Lido for arm and 100cc of .25% Lido for leg Inject slowly over 90 sec Produce effects in 5 mins After 45 min inflate distal tourniquet and then deflate proximal
Technique for the Infraclavicular Block
Supine, head opposite direction, ipsilateral arm 90 degrees Needle: 22g, 10 cm Insert @ 45 degree angle Brachial plexus stimulation is usually elicited between 5-8 cm 30-40 cc local
Functions of the glial cells (nerve glue) (4)
Support neuronal function by: -Creating a healthy ionic environment -Modulate nerve conduction -Controlling reuptake of neurotransmitters -Repairing neurons following neuronal injury
What is the treatment for CES?
Supportive
Which BP block is most likely to cause a *pneumothorax*? Why?
Supraclavicular block - the cupola of lung is just medial to 1st rib (higher on R side) - tall, thin pts at higher risk for ptx - consider PTX if pt coughs/complains of CP during needle insertion/manipulation
What is intracranial pressure?
Supratentorial CSF pressure
Pathophysiology of MH
T-Tuble is depolarized, extra cellular Ca+2 enters myocyte via dihydropyridine receptor which activates defective RyR1 receptor instructs the SR to release too much calcium into the cell More calcium is available to engage with contractile elements, so more is attempted to be returned via SERCA2, which consumes a lot of ATP creating increased O2 consumption and CO2 production
Where do most cerebral aneurysms arise from?
The circle of Willis
Where do you want to place the needle with a supraclavicular block?
The goal is to place the needle in the brachial plexus sheath in the vicinity of the subclavian artery and inject local anesthetic.
What is the exception in Sensory innervation of the UE?
The hand
Where does ALS often begin?
The hands - over time weakness spreads to the rest of the body: tongue, pharynx, larynx, chest
Which block has been associated with inevitable phrenic involvement and consequent hemidiaphragmatic paresis or paralysis?
The interscalene level brachial plexus block
What is above (superior) to the axillary artery?
The median nerve
Hypdrophilic vs lipophilic opioid profiles
The more hydrophilic a drug is the more likely it is to stay in the subarachnoid space and ascend toward the brain. The more lipophilic a drug is the more likely it is to diffuse into the systemic circulation
Which nerve do you miss with an axillary block?
The musculocutaneous
How can a pneumothorax develop during an inter-scalene block? Which side is at greater risk?
The needle can be too caudal -Right lung is at greater risk bc the cupola of the lung is higher on that side -sx: pt coughing and c/o chest pain during needle insertion/manipulation
If one side of the circle of wills becomes occluded then...
The other side should be able to perfuse the affected areas of the brain. * only holds true in 42-52% of the population- though there is ususally additional networks that provide redundancy
The transverse processes projects ___, while the spinous process projects ___. Muscular attachment to these regions provides stability and support. The spinous process also serves as a landmark to determine ___.
The transverse processes projects laterally, while the spinous process projects posteriorly. Muscular attachment to these regions provides stability and support. The spinous process also serves as a landmark to determine midline.
Why do hydrophilic drugs cause late respiratory depression?
They ascend rostrally where they can inhibit the respiratory center late phase is 6-12h
How do local anesthetics cause their effect in epidural anesthesia
They need to diffuse through the dura cuff before they can block the nerve roots -can also leak through intervertebral foramen to enter the paravertebral area
What are anesthetic goals for aneurysms? What do you do if aneurysm ruptures during induction?
Tight BP control during induction/intubation Reduce ICP and start cerebral protection methods
Tonic vs. clonic movements
Tonic = whole body rigidity Clonic = repetitive jerking motions
The axons form what kind of matter?
White matter d/t myelin
Hypokalemic periodic paralysis is present if skeletal muscle weakness follows...
a glucose-insulin infusion (weakness occurs after serum potassium is reduced)
Match the Intrinsic Laryngeal Muscle with its action on layrngeal movement? a)Aryepiglottic b)cricothyroid c)posterior cricoarytenoid d)thyroarytenoid
a)Aryepiglottic - closes glottic opening b)cricothyroid - lengthens vocal cords c)posterior cricoarytenoid - abducts vocal cords d)thyroarytenoid - adducts vocal cords
What is achieved with supraclavicular block?
achieves excellent anesthesia to the entire arm, including the hand (may still miss the ulnar nerve)
Why do neuraxial opioids cause N/V?
activation of opioid receptors in the area postrema of the medulla and in the vestibular apparatus
In DMD Ca+ can freely enter the cell causing what?
activation of proteases that destroy the contractile elements causing inflammation, fibrosis, cell death
Aldrete Score examines 5 variables
activity respiration circulation consciousness oxygen saturation
Familial Periodic Paralysis
acute episodes of acute skeletal muscle weakness, accompanied by changes in serum potassium concentration -dx is in the muscle tissue not the NMJ Hypokalemic = Ca+ ch problems Hyperkalemic periodic paralysis = Na+ ch problems
Guillain-Barre is also called...
acute idiopathic polyneuritis
Conus meddularis location
adult: L1-L2 Infant: L3
Bronchial blockers (3)
allow the isolated lung to be suctioned can be used if the patient requires nasotracheal intubation can be used for lung separation in the patient with a tracheostomy
How does clonidine affect LA?
alpha 2 agonist, weak local anesthetic. But act synergistic with with local anesthetic so it prolongs anesthesia/analgesia. produces sedation.
Which option initiates hypoxic pulmonary vasoconstriction?
alveolar hypoxia
What are intercostal blocks used for?
analgesia
Surgical treatment for SAH
aneurysm clipping or endovascular coiling surgical repair should take place 24-48 hours after initial bleed
intercostal brachial nerve
arises from T2 = not covered in a brachial plexus block Field block is required to anesthetize this nerve = block may help awake pt tolerate UE tourniquet
body movement associated w/ perctoralis twitch response
arm adduction
Guillain-Barre syndrome
ascending paralysis/muscle weakness that is preceded by influenza like illness
Airway complication of RA
atlantoaxial subluxation and separation of the atlanto-odontoid articulation Cause: weakening of the transverse axial ligament -> allows the odontoid to directly compress the spinal cord at the level of the foramen magnum -> risk for quadriparesis & paralysis
Duchenne presents with...
atrophy and painless muscle degeneration Progressive deterioration of skeletal muscle strength culminating in profound weakness (these pts often req surgical correction of scoliosis/contractures and rarely live past 30y)
Bradycardia treatment
atropine or glycopyrrolate
Temporal lobe
auditory cortex and language
Guillain-Barre pathophysiology
autoimmune attack on peripheral myelin - loss of AP conduction lasts 2-4 weeks
rheumatoid arthritis (RA)
autoimmune d/o of the synovial joints
systemic lupus erythematosus (SLE)
autoimmune disease characterized proliferation antinuclear antibodies Mostly women Does not involve the spine Butterfly rash
Nerve associated w/ deltoid twitch response
axillary
Which block is preferred for OP procedures?
axillary approach.
Axillary Block Ultrasound Image- what is the landmark to look for?
axillary artery
Best block for hand surgery?
axillary block.
Factors that affect spread of spinal anesthesia
baricity patient position does Site Volume of CSF Density of CSF
PDPH treatment
bed rest Hydration NSAIDs caffeine Epidural blood patch Sphenopalantine ganglion block
Upper motor neuron (corticospinal tract)
begin in the cerebral cortex and end in the ventral horn -cell body originates in the cortex
dura mater borders
begins at foramen magnum and ends at the dural sac
paravertebral
beside the vertebrae
When comparing dexmedetomidine to propofol for MAC, which statements better describe dexmedetomidine? (3)
better analgesia inferior amnesia longer onset
Respiratory depression caused by: Hydrophilic opioids: cause a ______ respiratory depression. Early phase results from_____ _______. Late phase resp depress results from opioid tendency to _________ to the _____ where they can inhibit resp center. When does the early phase occur? When does the late phase occur?
biphasic resp depression; early phase results from systemic absorption Late phase results from opioid tendency to ascend to the brain where they inhibit respiratory center Early phase occurs <6h Late phase 6-12h
What does air look like on a US?
black (hypoechoic)
Causes of Neuraxial bradycardia
blockade of T1-T4 -> relative increase of pSNS tone Unloading ventricular mechanoreceptors->Bezold-Jarisch reflex Unloading of the stretch receptors in the SA node
Bradycardia is caused by:
blockade of preganglionic cardioaccelerator fibers T1-T4 increase in parasympathetic tone unloading of ventricular mechanoreceptors----> Bezold-Jarisch reflex unloading of the stretch receptors in the SA node
Sacral cornu
bony nodules that flanks the sacral hiatus
What axis is best when placing an A-line?
both -When placing A-line: short axis to stick the artery and then switch to long axis to see if you're threading the artery correctly.
osteogenesis imperfecta
brittle bone disease = connective tissue d/o Possible difficult airway = c-spine precautions, cervical range of motion Kyphoscoliosis -> restrictive lung dx -> V/Q mismatch Blue sclera Increased serum thyroxine
How is the brachial plexus formed?
by the union of C5 - T1 with some minor contributions by C4 and T2 -As they exit the intervertebral foramina, they converge and form: trunks, divisions, cords and terminal nerves (musculocutaneous, median, radial, ulnar)
What are landmarks for the supraclavicular block?
clavicle, subclavian pulse -find pulse and go 2cm below.
When used during laparoscopic procedure, an LMA:
can be used if the procedure is less than 15minutes
hyperbaric trendelenberg
can cause high spinal before block is set Usually levels off at T4 w/ supine position. Can increase to T1 if put in Trendelenberg
Most common cause of ischemic stroke
cardio-embolitic event = afib
In the geriatric patient, what organ system is the primary cause of risk throughout the perioperative period?
cardiovascular
Cervical and thoracic spinal processes angle in the _____________ direction
caudal Requires more cephalad approach with needle
Radial nerve injury is caused by__ Presents with ___
caused by external pressure at the spiral groove of the humerus presents with wrist drop
Hyponatremia during aneurysm surgery is most commonly the result of...
cerebral salt-wasting syndrome- not SIADH
Hemodynamic instability (neurogenic shock) is greatest with injuries to ...
cervical or upper thoracic cord -the higher the injury, the greater degree of hemodynamic instability
Initial anesthetic considerations w/ TBI
cervical spine stabilization airway protection optimization of hemodynamics cerebral protection
vertebral column sections
cervical: C1-7 thoracic: T1-12 lumbar: L1-5 sacrum: S1-5 fused coccyx: 4 fused
cortisol synthesis is dependent on
cholesterol required to produce mineralocorticoids, glucocorticoids, and androgens
About 2% of those affected with Guillain-Barre will develop...
chronic inflammatory demyelinating polyneuropathy
most common site of cerebral aneurysm
circle of willis
where do the anterior and posterior circulation converge
circle of willis = its purpose is to provide redundancy in the blood flow to the brain, so if one part is compromised the other part can provide perfusion
What are the landmarks for supraclavicular block?
clavicle, subclavian artery
Relative contraindications to neuraxial analgesia
coagulopathy, Increased intracranial hemorrhage, sepsis, infection at sight, hypovolemia, valve lesion with fixed stroke volume, Scoliosis, arthritis, spinal fusion, osteoporosis, difficult airway, full stomach, peripheral neuropathy, multiple sclerosis
Cerebral cortex
cognition sensation movement
2 statements about neuraxial anesthesia in the morbidly obese patient
compared to normal weight patient, they are less tolerant of a high block. sitting position is preferred over the lateral position for block placement - improves landmark visibility
LeFort 1 Fracture
cribiform plate remains intact. oral and nasal intubations are safe
2 routes infectious organism can reach the CSF
contaminated needle (breech of aseptic technique) bacteria in patients blood at time of SAB
Most common periop eye complication
corneal abrasion
portions of spinal cord perfused by the anterior blood supply
corticospinal tract (flaccid paralysis) Autonomic motor fibers (bowel & bladder dysfxn) Spinothalamic tract (loss of pain & temp sensation) (touch and proprioception are from the dorsal column supplied by the posterior blood supply)
MS treatment
corticosteroids interferon azathioprine
CMRO2 is ___________ to cerebral blood flow
coupled = the higher the need for oxygen, the more blood will be there to satisfy the need
What is the 2nd messenger of nitric oxide?
cyclic guanosine monophosphate
Eaton-Lambert Syndrome
d/o of the NMJ Antibodies block presynaptic calcium channels which blocks the release of Ach from the presynaptic neuron - IgG mediated destruction post-synaptic Ach receptors are normal
Complete spinal cord injury
damages upper motor neuron -> leads to flaccid paralysis, loss of sensation below the level of the injury, & bowel & bladder dysfxn After acute phase, spinal reflexes return and may lead to spasticity
Epidural anesthesia site of action
diffuse through dural cuff Block nerve roots Leak into intravertebral foramen, cause of paravertebral blocks
lateral corticospinal tract
fibers that innervate the limbs crossover to the contralateral side in the medulla, then descend through the lateral corticospinal tract
20-40 min of bier block
deflate and reinflate
Ulnar nerve block
derived from medial cord of the brachial plexus elbow flexed 90 degrees, injected b/w the olecranon and medial epicondyle
Median nerve block
derived from the lateral and medial cords of the brachial plexus In the antecubital fossa, inject medial to the brachial artery *do not use this block in a patient w/ carpal tunnel syndrome
Radial nerve block
derived from the posterior cord of the brachial plexus inject between the biceps tendon and brachioradialis
Baricity
describes a local anesthetic solution relative to CSF
Cobb angle
describes the magnitude of spinal curvature in scoliosis -2 most displaced vertebrae at the top and bottom are compared
which drugs are least likely to cause postoperative cognitive dysfunction in the elderly? (desflurane, atropine, remifentanil, morphine, midazolam, glycopyrrolate)
desflurane remifentanil glycopyrrolate
First order neuron (Dorsal)
detects a stimulus and transmits a signal to the spinal cord -enters through the dorsal root ganglion -ends in the medulla -Ascends on ipsilateral side (same side it enters on) -Synapses w/ 2nd order neuron in the medulla
C3-5 myotome
diaphragmatic muscle
patient with hx of chronic pain presents with MI. Hx of gastric ulcer and renal impairment. Pt is most likely receiving chronic therapy of: (diclofenac, amitryptyline, oxycodone, imipramine)
diclofenac non-selective cyclooxygenase(COX) inhibitor
Epidural needles
differ by angle of tip Crawford = 0 Hustead = 15 Tuohy = 30
myasthenia gravis s/s
diplopia, ptosis (early signs) Bulbar muscle weakness (muscles of mouth & throat) -> dysphagia, dysarthria, and difficulty handling saliva DOE Proximal muscle weakness
Risk for postop mechanical ventilation in patients with MG is increased with...
disease duration >6 years daily pyridostigmine >750mg/day vital capacity <2.9L COPD median sternotomy> transcervial thymectomy
arterial cerebral circulation
divided into anterior and posterior -> converge at the circle of Willis
Where do the cell bodies of second order neurons of the spinothalmic tract reside?
dorsal horn of spinal cord
Where do sensory neurons enter the spinal cord?
dorsal root
The syndrome associated with Duchenne muscular dystrophy is not true MH, but is instead...
due to rhabdomyolysis, not defective RyR1 receptor Not treatable with dantrolene
Where does the subarachnoid space terminate?
dural sac
Increased risk for postop mechanical ventilation w/ myasthenia gravis
duration > 6 years Daily pyridostigmine > 750mg/day Vital capacity < 2.5L COPD Median sternotomy > transcervical approach
What divide the muscular compartments from potential spaces?
fascial membranes.
Factors that have no effect on PDPH
early ambulation Continuous spinal catheter (if placed after spinal block)
Factors that do not increase the risk of TNS
early ambulation LA concentration Baricity glucose concentration
Infraclavicular indications and landmarks
elbow, forearm, and hand NOT above elbow Landmarks: Coracoid process, clavicle, Axillary artery and vein
Amygdala
emotion appetite responds to pain and stressors
Burn patient with bronchoscopy that reveals grade 3 injury. What is the best intervention
endotracheal intubation
First order neuron (Anterolateral)
enters through dorsal root ganglion Cell body in the dorsal root ganglion Ascends or descends 1-3 levels on the ipsilateral side via Lissauer tract b/f synapsing with the 2nd order neuron Synapses with the 2nd order neuron in the dorsal horn laminae I, IV, V, VI
What is contraindicated with a wrist block
epi solutions
Result of injecting local anesthetic into the subdural space
epidural dose: high spinal spinal dose: failed spinal
major complication of neuraxial anesthesia
epidural hematoma -> compresses the dura -> spinal cord ischemia tx: surgical decompression w/in 8h
intrathecal vs epidural opioid dosing
epidural opioids need to diffuse through the epidural space and the dural cuff so only a fraction reaches the spinal nerve -> need a higher dose
What nerves are covered in a 3-in-1 Block?
femoral n. lateral femorocutaneous n. obturator n.
where is the musculocutaneous nerve found?
found in the fascial layers between biceps and coracobrachialis muscles.
Anterolateral peripheral receptors
free nerve endings nociceptors
grand mal seizure (tonic-clonic seizure)
generalized seizure tonic phase = whole body rigidity clonic phase = jerking movements respiratory arrest -> hypoxia increased brain activity -> ↑CMRO2
Malignant hyperthermia
genetic disease characterized by disordered calcium homeostasis - dysfunctional ryanodine receptor (doesn't turn off, ca+ keeps pumping out) SERCA pump also keeps working. They both use up ATP causing lactic acidosis
Where do most neurologic tumors arise from
glial cells
Region that is anesthetized by the glossopharyngeal nerve block
glossopharyngeal nerve (CN9) innervates the posterior 1/3 of the tongue to the topside of the epiglottis. this includes the vallecula. Services the afferent limb of the gag reflex
laminae
grey matter is subdivided into 9 laminae Laminae I-VI: dorsal grey matter, sensory Laminae VII-IX: ventral grey matter, motor
Area of spinal cord where pain modulation occurs
grey matter of the spinal cord (the butterfly) contains neuronal cell bodies
Familial periodic paralysis
group of diseases characterized by intermittent attacks of skeletal muscle weakness associated w/ hypo or hyper-kalemia
Myotonic Dystrophy
group of diseases where the hallmark is prolonged muscle contracture (myotonia) after a voluntary skeletal muscle movement
What is a tract in the spinal cord?
group of fibers inside the white matter that relay info up/down the spinal cord to/from the brain
Spinal tracts
group of fibers inside the white matter that relay information up and down the spinal cord
Axillary block complications
hematoma (hold pressure for 3-5min) LAST
Valproic Acid (Depakote) s/e
hepatotoxicity thrombocytopenia (surgical bleeding - esp. in kids) Displace phenytoin from plasma proteins
Respiratory depression with opioids is more common with: (6)
hi doses co-admin of sedatives low lipid solubility old age naivety increased intrathoracic pressure
The level of autonomic blockade is _______ than sensory and motor block (Spinal Anesthesia)
higher 2 to 6 dermatones higher than sensory
If ICP is elevated, CPP requires a ______________ MAP to maintain CPP
higher = if MAP is low w/ a high ICP you risk ischemia
Hyperbaric
higher density than CSF - sinks
Risks of cutting needles
higher risk of PDPH less tactile feel Needle more easily deflected More likely to injure cauda equina
Procaine 10% in water is __________ Due to Containing a lot of molecules
hyperbaric
Anesthetic considerations for mastectomy with sentinel node biopsy (2)
hypercalcemia is common - MC metastisis is bone SpO2 may become inaccurate during surgery - if isosulfan blue dye is injected to locate a sentinel node
What do nerve roots look like on a US?
hyperechoic (white)
What increases CMRO2
hyperthermia ketamine N2O (Hyperthermia >42 degrees denatures proteins and destroys neurons)
Physiologic changes associated with acrylic bone cement include
hypotension from cement monomer absorption hypoxemia from air or fat embolism increased PVR cardiac arrest from right HF unexpected LOC during RA
S/S of neurogenic shock
hypotension, bradycardia, hypothermia w/ pink, warm extremities sympathectomy below the injury can last 1-3 weeks
S/S of Hypovolemic shock
hypotension, tachycardia, and cool, clammy extremities
What decreases CMRO2
hypothermia halogenated agents propofol etomidate barbituates
Diagnosis of Hypokalemic periodic paralysis
if muscle weakness follows a glucose-insulin infusion
Diagnosis of Hyperkalemic periodic paralysis
if muscle weakness follows oral potassium administration
Lower motor neuron injury signs/symptoms
impaired reflexes and flaccid paralysis
hypobaric supine
in supine position it rises to lower lumber region in sitting position it rises toward the brain (bad)
Laminae I - VI reside...
in the dorsal grey matter
majority of post-tonsillectomy hemorrhage occur
in the first 6hrs(75%), 24hrs(25%)
What is the most favorable place to find the nerves of the brachial plexus
in the space of the supraclavicular triangle.
Laminae VII - IX reside...
in the ventral grey matter
Masseter muscle spasm is due to...
increased calcium in the myoplasm Site of action is distal to the NMJ, so a NMBD won't relax the jaw
For every 1mmHg increase in PaCO2, CBF...
increases by 1-2mL/100g/min Linear relationship between PaCO2 and CBF
Affect of obesity and pregnancy on epidural space
increases intra-abdominal pressure -> causing engorgement of baston's plexus ->decreases the volume of the epidural space -> increased risk of needle injury of cannulation during neuraxial techniques
Ehlers-Danlos syndrome
inherited disorder of collagen & procollagen — primarily your skin, joints and blood vessel walls. Coagulopathy -> spontaneous bleeding into the joints * AAA Avoid regional anesthesia & IM injections
Charcot-Marie-Tooth disease
inherited peripheral neuropathy. Presents as skeletal muscle weakness and wasting. Usually confined to lower third of legs, but can also affect the quadriceps, hands, forearms
Neurendocrine affects of neuraxial anesthesia
inhibition of afferent traffic from the surgical site diminishes the surgical stress response. ↓circulating catecholamines, renin, angiotensin, glucose, thyroid stimulating hormone, growth hormone
Sphenopalantine ganglion block
inserting two qtips into the posterior wall of the nasopharynx
Where do spinal nerves exit the vertebral column?
intervertebral foramina
how is the epidural space connected to the paravertebral space
intravertebral foramina
When using a spinal needle that is 22g or smaller use an:
introducer needle
Most common cause of periop vision loss
ischemic optic neuropathy (ION) = inadequacy of blood supply to the optic nerve -not associated with pain -occur w/in 24-48h after surgery -caused by external compression of the glob (most common) or embolism (CPB) s/s: cherry red macula with surrounding pale retina
Hyperkalemia treatment
iv calcium gluconate/ chloride insulin and glucose Hyperventilation Beta agonists bicarb lasix
Where does venous blood flow exit the brain
jugular veins
What should be avoided in the patient with myelomeningocele? (lateral, desflurane, succs, latex)
latex
Posterior borders of the epidural space
ligamentum flavum vertebral lamina
Neuraxial opioids effect on the fetus
lipophilic will have greater effect b/c more cross into systemic circulation
What systems are unchanged by neuraxial anesthesia
liver and kidneys
Is a long or short needle used in the Infraclavicular Block?
long
Treatment for vasospasm is aimed at?
maintaining CPP CPP=MAP-ICP or CVP (whichever is higher) -idea is that ischemic areas in brain are already max vasodilated so perfusion to areas are pressure dependent
Duchenne is more common in...
males
Which measures the concentration of anesthetic by bombarding the gas sample with electrons?
mass spectrometry
Absolute indications for single lung ventilation (3)
massive hemorhage unilateral lung lavage control of ventilation of only one lung (bronchopleural fistula(major bronchial trauma
All of the following are displaced by a jaw thrust except
mastoid process is fixed and does not move with the mandible
Why do you see SOB in an interscalene block?
may be due to paralysis of phrenic nerve or may indicate a pneumothorax. Reason why you only do one shoulder at a time
Nerve associated w/ bicep twitch response
musculocutaneous
The *saphenous n.* provides SENSORY innervation to what 2 structures?
medial aspect of knee medial malleolus
Axillary approach to brachial plexus block, blocks what nerves (4)
median ulnar radial musculotaneous NOT the axilary nerve
S/sx alzheimers:
mem loss apraxia aphasia agnosia difficulty speaking and forming words
Hippocampus
memory learning
Hydrophilic opioids
meperidine Hydromorphone Morphine Stays in CSF longer, Wider spread Rostral Substantial gelatinosa Rexed lamina II & III Delayed onset, longer duration Early and late respiratory depression Higher nausea vomiting and pruritus
triad of obesity, htn, and dm2 is known as
metabolic syndrome
Babinski sign
method to test the integrity of the corticospinal tract normal: plantar flexion (downward pointing of toes) abnormal: plantar extension (fanning toes)
Why to use a Tuohy
minimizes the risk of dural puncture
Horner's syndrome consists of what?
miosis, anhydrosis (lack of sweating), ptosis (eye/facial droop), and nasal congestion
characteristics of urinary retention w/ neuraxial opioids
more common in young males more common w/ neuraxial opioids vs other routes caused by inhibition of sacral parasympathetic tone reversed w/ naloxone
Broca's area
motor control of speech
Frontal lobe
motor cortex
Feedback loop implicated in Parkinson's
motor cortex -> basal ganglia & cerebellum -> back to cortex via the thalamus (suppresses the motor cortex)
Acute spinal cord injuries are most often caused by...
motor vehicle accident fall assault sports injury
3 types of neurons
multipolar: most CNS neurons pseudounipolar: dorsal root ganglia, cranial ganglia bipolar: Retina, ear
Lower motor neuron involvement in ALS presents as...
muscle weakness, fasciculations, and atrophy
The BBB is poorly developed in...
neonates
How does a subarachnoid hemorrhage result in death
obstructive hydrocephalus Rebleeding Vasospasm
*When do you use triple H therapy and nimodipine?
only if aneurysm has ruptured
What controls cerebral vascular resistance?
pH of CSF around arterioles
Most common problem w/ Pagets
pain and bone fractures
All venous blood exits the brain via the...
paired jugular veins
Region of the arm that is supplied by the median nerve
palm of hand ventral region of thumb Distal portions of index, middle and medial half of ring finger
If too anterior with interscalene block, what will you see?
phrenic stimulation -need to raise the needle
ANP increases all of the following except: (water excretion, GFR, sodium excretion, plasma volume)
plasma volume facilitates natriuresis by increasing GFR and facilitating sodium and water excretion
Guillane Barre treatment
plasmapheresis &/or IV IgG (Unlike MS - steroids and interferon do not help)
Diagonstic criteria for type 2, but not type 1, complex regional pain syndrome include:
previous nerve injury
ependymal cells
produce cerebrospinal fluid form the choroid plexus - located in all 4 ventricles
amyotrophic lateral sclerosis (ALS)
progressive degeneration of motor neurons in the corticospinal tract Upper and lower motor neurons are affected
Transverse processes
project laterally from the right and left sides of the vertebral arch muscular attachment
spinous process
projects posteriorly Denotes the midline
Myotonic Dystrophy
prolonged contracture after voluntary muscle contracture Cause: dysfunction ca+ sequestration by the sarcoplasmic reticulum Contractures can be so severe they interfere w/ intubation and ventilation
Clinical presentation of Eaton-Lambert
proximal muscles are most affected weakness is worst in the morning and gets better throughout the day weakness of respiratory and diphragm muscles ANS dysfxn cause orthostatic HoTN, slowed gastric motility, urinary retention
The *lumbar plexus* forms posterior to the ________________ and anterior to the __________________.
psoas muscle quadratus lumborum muscle
Secondary signs of Parkinson's
psychosis depression dementia loss of facial expression diaphragmatic spasm oculogyric crisis
Horner's syndrome symptoms
ptosis, myosis, anhydrosis
T12 dermatome
pubic symphysis
how do you check the musculocutaneous nerve and what pt. action will you see?
pull and pt. will flex arm with bicep
how do you check the radial nerve and what pt. action will you see?
push and pt. will extend arm with triceps
Cushings triad
r/t ICP = HTN, bradycardia, irregular respirations
What are the target primary nerves of the axillary block?
radial, median, ulnar (all contained in a neurovascular sheath around the axillary artery) musculocutaneous which is not in the sheath
3 terminal nerves that can be blocked at the forearm or wrist
radial, ulnar, median
The thoracolumbar region of the anterior spinal cord is highly dependent on ______ _______ and interruption of it can cause ______ to the corresponding spinal cord segments
radicular arteries interruption can cause ischemia or infarction
Local anesthetics effect on seizures
reduce the seizure threshold, but regional anesthesia does not increase the risk for seizures
gastric contents in the barrel of the LMA classic. Appropriate next step?
remove the LMA
myastehnia gravis: _______________ to Succ
resistant b/c there is reduced Ach nicotinic receptors at the NMJ -increase RSI dose 1.5-2mg/kg
Main treatment for alzheimer's
restore concentration of Ach cholinersterase inhibitors = increase pSNS tone (can see bradycardia, syncope, N/V) If anticholinergic is need use glyco (does not cross BBB) (prolongs Succ)
Anesthetic mgmt if aneurysm ruptures during procedure
reverse heparinization with protamine lower MAP into low/normal range
SLE Anesthetic Considerations
risk of postextubation laryngeal swelling and airway obstruction (smaller ETT) risk for hypercoaguability & thrombosis (stroke, DVT, PE) Cyclosporine prolongs succ
Robert Taylor Drinks Cold Beer means what?
roots, trunks, divisions, cords, branches
status epilepticus
seizure activity > 30 min or 2 grand mal seizures w/out regaining consciousness in b/w respiratory arrest -> hypoxia increased brain activity -> ↑CMRO2 treatment: phenobarbital, thiopental, phenytoin, benzos, propofol, general anesthesia
intervertebral discs
separate the vertebrae degeneration decreases the size of the intervertebral foramina and can cause nerve compression
Most common cause of death in a patient with LVAD
sepsis
TNS s/s
severe back and butt pain that radiates to both legs develops within 6-36 h and persists for 1-7 days
What agent is most likely to cause a fire inside the breathing circuit?
sevoflurane
Shape of epidural space
shallow anteriorly but deep posteriorly especially in the lumbar region
interscalene block indications & landmarks
shoulder, arm, and elbow surgery Landmarks: Clavicular head of the sternocleidomastoid and cricoid cartilage
Parietal lobe
somatic sensory cortex
The risk of epidural hematoma is _____________ during block placement and catheter removal
similar
isobaric
similar baricity to CSF - stays at injection site
injury above the level of decussation in the medulla
spastic paralysis on the contralateral side of the body
Upper motor neuron involvement in ALS presents as...
spasticity, hyperreflexia, and loss of coordination
Telangiectasia
spider veins in CREST syndrome can cause mucosal bleeding
Absolute Contraindications to Caudal blocks
spina bifida meningomyeloceleof the sacrum Meningitis
Orientation of ___ can differentiate lumbar, thoracic, cervical vertebra
spinous process
autonomic hyperreflexia pathophysiology
stimulation below the level of the SCI -> HTN -> bradycardia -> body attempts to reduce afterload above the level of the injury (hypotension)
Most common source of post-spinal bacterial meningitis
streptococcus viridans
Clinical presentation of Cricoarytenoid arthritis
stridor, hoarseness, dyspnea -> airway obstruction edema or erythema of vocal cords risk for postextubation airway obstruction
dystrophin
structural protein of the cytoskeleton in skeletal and cardiac muscle cells. Helps anchor actin and myosin to the cell membrane Also allows extrajunctional receptors to populate the sarcolemma -> hyperkalemia (this is why people w/ DMD should not get Succ)
The vertebral arteries are branches off the...
subclavian arteries
Technique to decrease the absorption of opthalmic topical local anesthetic into the systemic circulation
tell the patient to keep the eye shut for 1minute increases absorption by the eye and reduces drainage into nasal mucosa
Which drugs show a prolonged effect in the patient with a dibucaine number of 20?
succinylcholine benzocaine 20= atypical homozygous pseudocholinesterase deficiency
Which neuraxial opioid causes the most sedation
sufentanil
Patient has visceral pelvic pain after receiving radiation for rectal cancer. Which procedure is most likely to provide pain relief for this patient
superior hypogastric plexus block superior hypogastric plexus innervates the pelvic organs
Arachnoid villi location
superior sagittal sinus
Trunks
superior: C5-C6 middle: C7 inferior: C8-T1
Cauda equina treatment
supportive
What is one of the easiest blocks to do with US?
supraclavicular block
Neuraxial opioids do not causes:
sympathectomy Skeletal muscle weakness Changes in proprioception
Neuraxial opioids do NOT cause:
sympathectomy skeletal muscle weakness changes in proprioception
GI affect of neuraxial anesthesia
sympathetic inhibition allows unopposed parasympathetic stimulation -> relaxation of sphincters and increased peristasis
Autonomic dysfunction with Guillain-Barre presents as...
tachycardia or bradycardia, HTN or hypotension, diaphoresis or anhidrosis, and orthostatic hypotension
The most common site of transtentorial herniation
temporal uncus - herniation of this area puts pressure on CNIII (oculomotor) and causes blown pupils, reflects pressure on the midbrain
Akinetic seizure
temporary LOC and loss of postural tone -can lead to a fall -> head injury -more common in children
What part of the airway would you expect reynolds number <2000
terminal bronchioles molecules travel parallel center of the tube is fastest, near the walls is the slowest laminar flow
A generalized seizure occurs when...
the activity affects both hemispheres of the brain
The anterior spinal artery perfuses...
the anterior 2/3 of the spinal cord (yellow area)
The Babinski test tests the integrity of...
the corticospinal tract
Effect of PaCO2 on CBF
the pH around arterioles effects their diameter ↑PaCO2 (↓pH) causes vasodilation = for every 1mmHg increase in PaCO2 -> CBF increases 1-2mL/100g tissue/min
The posterior spinal arteries perfuse...
the posterior 1/3 of the spinal cord (green area)
Gay-Lussac's Law
the pressure of a gas is directly proportional to the Kelvin temperature if the volume is constant
The corticospinal tract is often referred to as...
the pyramidal tract -the pyramids are formed by the corticospinal neurons as they run through the medulla
What is posterior and inferior to the axillary artery?
the radial and ulnar nerve.
spinal facet joints
the superior articular process of one vertebrae & the inferior articular process of the vertebrae directly above
When it comes to regional anesthesia/analgesia of the shoulder, arm and hand, which approach can do it all?
the supraclavicular approach to the brachial plexus is the one block that can do it all!
Why are steroids contraindicated w/ TBI
they cause hyperglycemia -> acidosis
What part of the spine is generally not affected by RA?
thoracolumbar spine
Best surgical treatment for the patient with myasthenia gravis
thymectomy in MG thymus gland produces antibodies that destroy the postjunctional nicotinic receptors at the NMJ
Aqueduct of Sylvius
transports CSF b/w 3rd and 4th ventricle
If too posterior with interscalene block, what will you see?
trapezius stimulation -need to drop the needle
Second order neurons of the dorsal column are joined by the...
trigeminal nerve
tic douloureux
trigeminal neuralgia (CN V) Excruciating pain in the face
Supraclavicular block level
trunks/divisions
Methods to reduce cerebral mass
tumor debulking hematoma evacuation
What nerve is most likely to get injured in the OR?
ulnar
T10 dermatome
umbilicus
Which of the following herbal agents reduce MAC (2) (ginko biloba, garlic, valerian, kava kava)
valerian, kava kava
The most frequent manifestation of sickle cell disease is:
vaso-occlusive crisis
CV affects of Neuraxial anesthesia
vasodilates arterial and venous, but mainly affects venous capacitance. ↓venous return, CO & BP treat w/ volume
Leading cause of morbidity and mortality after subarachnoid hemorrhage
vasospasm
What is the most significant thing to monitor postop?
ventilatory failure
Where do motor and autonomic neurons exit?
ventral nerve root
The venous blood from the basal brain structures drain...
via the inferior sagittal sinus, vein of Galen, and straight sinuses
The venous blood from the cerebral cortex and cerebellum drains...
via the superior sagittal sinus and dural sinuses
occipital lobe
visual processing
With epidural anesthesia , _____________ is the primary determinant of spread
volume
Anticoagulated pt w/ TBI
warfarin reversal: FFP, prothrombin complex concentrate, recombinant factor VIIa Anti-platement med: Platelet infusion
Monroe-Kellie Doctrine
when one content in the skull increases, another must decrease to compensate and maintain normal ICP
RA is 2-3 times more common in...
women
S/S of subarachnoid hemorrhage
worst HA of their life N/V photophobia fever When blood blocks CSF, ICP increases
T6 dermatome
xiphoid process
Is the infraclavicular block more painful than interscalene or supraclavicular?
yes
Cardiac considerations of scoliosis
↑PVR -> RV hypertrophy Mitral valve prolapse Mitral valve regurg Coarctation of the aorta
A GCS of what indicates need for ICP measurement?
≤7
What does one vial of ryanodex contain?
250mg Requires 5mL of sterile water to reconstitute
An *interscalene block* is best for procedures involving the _____________ and the ______________.
- shoulder - proximal upper extremity
The cuff should be inflated to around
250mmhg or at least 100mmhg over SBP
Spinal cord has how many paired spinal nerves?
31
Number of paired spinal nerves
31 -formed by a dorsal (posterior/sensory) and ventral (anterior/motor & autonomic)
Where do you inject LA for a *radial n.* block at the wrist? Why?
- subq injection (field block) of 10mL proximal to radial styloid - field block needed b/c several branches of radial n. at this point in wrist
What are the anatomic landmarks of an *ulnar n.* block at the wrist?
- ulnar styloid - ulnar pulse - flexor carpi ulnaris tendon
4 Types of glial cells
-Astrocytes -Oligodendrocytes -Microglia -Ependymal cells
Big picture of the Lumboscral Plexus anatomy
* commom fibular nerve is another name for common peroneal nerve
Supraclavicular complications
**Pneumo (highest of all the blocks) - cupola of the lung is just medial to the first rib Horner's syndrome Subclavian artery injection (aspirate!)
Infraclavicular complications
**Venous inj (higher than supraclav) pnemo (lower than supraclav) discomfort rarely blocks the phrenic nerve
Factors that increase the risk of cauda equina
5% lidocaine and spinal micro catheters (focus high concentrations of LA in one area)
Considerations with Marfan's
-Minimize wall stress for aortic dissection with beta blockers -Careful with PIP (d/t spontaneous pneumothorax risk) -Careful with positioning -Pregnancy increases the risk of CV complications
Describe the technique for an epidural blood patch
*Definitive tx for PDPH* - sterile technique - draw 10-20cc of venous blood - reintroduce blood into epidural space
Name the 5 terminal nerves and their origins at the level of the ankle
*Femoral n.* 1. saphenous n. *Sciatic n.* 2. deep peroneal n. 3. sup. peroneal n. 4. sural n. 5. post. tibial n.
Describe the anatomical position of the *lateral femoral cutaneous n.*
- emerges at midpoint of psoas muscle - travels laterally along anterior iliac spine - passes under lateral border of inguinal ligament
*Hydrophilic* Opioids: CSF spread
- extensive - wide band of analgesia - more rostral spread (to brain)
What are the 4 types of *non-cutting* tip spinal needles?
*Pencil Point*: 1. Whitacre (small rectangle hole on shaft) 2. Sprotte (narrow oval hole on shaft) 3. Pencan *Rounded Bevel*: 4. Greene (triangular hole near bevel)
What are the anatomic landmarks for a *median n.* at the wrist?
- flexor carpi radialis tendon - flexor palmaris longus tendon
Classic presentation of PDPH
- fronto-occipital HA - n/v - photophobia - diplopia - tinnitus Sitting = worsens Supine = relief
Describe the anatomical position of the *sciatic n.*
- 2 nerves w/in a sheath (tibial n. + peroneal n.) - exits pelvis inferior to piriformis m. via the great sacrosciatic foramen
Describe the anatomical position of the sciatic n.
- 2 nerves w/in a sheath (tibial n. + peroneal n.) - exits pelvis inferior to piriformis m. via the great sacrosciatic foramen
How do you perform a field block for the intercostobrachial nerve?
- ABDuct and externally rotate arm, begin @ detloid prominence and move inferiorly - Total vol of LA = 5mL
Describe the anatomical position of the *femoral n.*
- Biggest of the 3 nerves - forms near middle and lower 3rd of psoas muscle - courses distally in groove created by psoas major and iliac muscle - continues under inguinal ligament - lies anterior to iliopsoas muscle, lateral to to femoral a. -splits into anterior and posterior branch- gives rise to saphenous nerve near knee
What are the 4 CONS of cutting tip spinal needles (Quincke + Pitkin)?
- Higher risk of Post Dural Puncture Headache (PDPH) - Less tactile feel - Needle more easily deflected - More likely to injure cauda equina
What factors *increase* the specific gravity of CSF?
- hyperglycemia - uremia - high protein content - advanced age - cold temp *increased viscosity
Most common co-existing heart condition with scoliosis? -Other heart complication with scoliosis
-Mitral valve prolapse -Mitral regurgitation and coarctation of the aorta may also occur
Where do you inject LA for an *ulnar n.* block at the wrist?
- Inject 3-5mL medial to and below Flexor Carpi Ulnaris tendon - Confirm negative aspiration d/t proximity of ulnar artery
What are the 4 PROS of non-cutting tip spinal needles (Whitacre, Sprotte, Pencan, Greene)?
- Lower risk of PDPH - More tactile feel - Needle less likely to deflect - Less likely to injure cauda equina
Sensory innervation of the UE: VENTRAL PORTION
- Median n. - Ulnar n. -Musculocutaneos n. (lateral + medial cords)
What is the treatment for TNS?
- NSAIDs - Opioids - Trigger point injections
*Coccygeal Plexus* Primary Nerves
- Pudendal - Inferior Anal - Perineal
What is the name of the *cutting tip* spinal needle?
- Quincke - Pitkin "pitkin cut"
Sensory innervation of the UE: DORSAL PORTION
- Radial n. - Axillary n. (posterior cord)
Which surgical procedures are NOT well suited for an *axillary block*?
- Upper extremity ABOVE elbow
Which surgical procedures are best with an *axillary block*?
- Upper extremity DISTAL to elbow (forarm /hand)
Describe the anatomical position of the *obturator n.*.
- arises from medial border of psoas at level of sacroiliac joint - travels distally into pelvis minor thru obturator canal
Describe the anatomical position of the obturator n.
- arises from medial border of psoas at level of sacroiliac joint - travels distally into pelvis minor thru obturator canal
What factors DO NOT significantly affect spread of LA in the subarachnoid space? (7)
- barbotage - inc. intra-abd pressure (coughing, labor) - speed of injection - orientation of bevel - addition of vasoconstrictor - weight - gender
Treatment for PDPH (6)
- bed rest - hydration - NSAIDs - caffeine - epidural blood patch -sphenopalantine ganglion block
What are the signs and symptoms of CES?
- bowel/bladder dysfxn - sensory deficits - weakness and/or - paralysis
Describe the anatomical position of the *musculocutaneous nerve*
- contained w/in coracobrachialis muscle - coracobrachialis m. not contained in sheath surrounding axillary a. - must be blocked separately
How do neuraxial opioids reduce neurotransmission in the substantia gelatinosa?
- decreased cAMP - decreased Ca+2 conductance (pre-synaptic neuron) - increased K+ conductance (post-synaptic neuron)
Cerebral autoregulation is mediated by... (3)
-Products of local metabolism -Myogenic mechanisms -Autonomic innervation
The *psoas compartment* block targets which 3 major nerves of the lumbar plexus?
- lateral femoral cutaneous n. - femoral n. - obturator n.
List 3 descriptors of the anatomical position of the *lumbar plexus* within the *psoas compartment*
- lateral to the vertebral column - anterior to quad lumborum muscle - posterior to psoas muscle
What factors *decrease* the specific gravity of CSF?
- liver dz - jaundice - warm temp
How does an epidural hematoma present?
- lower extremity weakness - numbness - lower back pain - bowel and bladder dysfxn
*Lipophilic* Opioids: CSF spread
- minimal - narrow band of analgesia - less rostral spread
What causes transient neurologic symptoms (TNS)?
- patient positioning - stretching of sciatic n. - myofascial strain - muscle spasm *NOT likely that neurotoxicity is a cause
The *sciatic n.* provides MOTOR innervation to______________.
- posterior thigh - lower leg + foot via branches (tibial + common peroneal)
Horner's Syndrome is indicated by which 3 symptoms?
- ptosis - miosis (pupil constriction) - anhidrosis
Describe the anatomical position of the *sciatic n.* in the proximal popliteal fossa
- sciatic n. is posterior + lateral to popliteal artery + vein - sciatic n. is bordered medially by semitendinosus + semimembranosus muscles - sciatic n. bordered laterally by biceps femoris muscle
What are the signs and symptoms of TNS?
- severe back and butt pain that radiates to both legs - develops w/in 6-36 hours - persists 1 - 7 days
What is the physiological explanation of the *Bezold-Jarish* reflex?
- venous pooling in lower extremities = decreased venous return - combo effects of an unloaded ventricle, SNS stim, and epi uptake (from block) = profoundly underfilled ventricle - underfilled ventricle slows HR to increase diastolic filling time
Fentanyl Intrathecal dose Epidural dose Epidural Infusion dose
-10 - 20 mcg -50-100mcg -25-100mcg
Ligamentum Flavum -How many flava -Form the ___ margins of the epidural space -Thinnest/thickest in the lumbar region -Piercing the ligamentum flavum contributes to what when passing a needle into the epidural space
-2 flava that run the length of the spinal canal -Form the dorsolateral margins of the epidural space -Thickest in the lumbar region -Piercing the ligamentum flavum contributes to the loss of resistance when the needle enters the epidural space
Dantrolene dose for MH When should you stop giving it? What is a common SE?
-2.5mg/kg IV q5-10 minutes -Stop dantrolene when sx of hypermetabolism reside -Venous irritation common
Continuous Femoral Nerve Block Provides analgesia for ________ After a bolus, what is the rate the LA should infuse? What are the common drugs used?
-48h -8-10ml/hr -0.2% ropi or 0.25% bupi
Sufentanil Intrathecal dose: Epidural dose: Epidural Infusion dose:
-5 - 10 mcg -25 - 50 mcg -10 - 20 mcg/hr *half of fentanyl dose
Sacrum consists of how many vertebra? -Superior iliac spines coincide with __ which denotes the location of __ in adults
-5 sacral vertebrae -Superior iliac spines coincide with S2 which denotes the location of dural sac in adults (dural sac ends at S3 in neonates)
Etiology of scoliosis
-80% are idiopathic -Congenital -Myopathic (muscular dystrophy, amyotonia congenita) -Neuropathic (cerebral palsy, syringomyelia, friedreich's ataxia) -Traumatic
Microglia function
-Act as macrophages and phagocytize neuronal debris
Familial periodic paralysis
-Acute episodes of skeletal muscle weakness accompanied by changes in serum potassium -Disorder of skeletal muscle membrane, not the NMJ *2 variants of the disease hypoK and HyperK
Medical management of RA -Aim -Drugs
-Aim to reduce inflammation with antirheumatics, glucocorticoids and NSAIDs
Medical treatment of SLE -Aim -Meds
-Aims to suppress immune system and reduce inflammatory response -Corticosteroids, NSAIDs, immunosuppressants (cyclophosphamide, azathioprine, methotrexate, mycophenolate mofetil) , and antimalarials (hydroxychloroquine and quinacrine) *Cyclophosphamide inhibits plasma cholinesterase and increases duration of succs
Complications of scleroderma -Airway -Lungs -Heart -Blood vessels -Kidneys -Peripheral and cranial nerves -Eyes
-Airway: skin fibrosis limits mouth opening -Lungs: pulmonary fibrosis, pulm HTN -Heart: dysrhythmias and CHF -Blood vessels: decreased compliance, HTN -Kidneys: renal failure, renal artery stenosis -Peripheral and cranial nerves: neuropathy d/t nerve entrapment by tight connective tissue -Eyes: dry eyes predisposing to corneal abrasions
How do you preform a wake up test?
-Anesthetic agents turned off to wake patient. Patient is asked to move hands and feet. Patient then re-anesthetized -If pt is unresponsive: wait or reverse reversible agents (NMB, opioids, benzos) -If pt can move hands but not feet, the surgeon should reduce distraction of the spinal rods
When are motor evoked potentials (MEP) used? -Motor or sensory function? -Can you use NMB?
-Anterior cord -Anterior spinal artery -Monitor motor function -Do NOT use NMB
What ligaments should the needle NEVER pass through with either the midline or paramedian approach to the epidural space?
-Anterior longitudinal ligament -Posterior longitudinal ligament
Draw a diagram of the anatomy of a vertebrae
-Anterior segment -Posterior segment -Lamina -Pedicale -Body -Transverse process -Spinous process -Facet (aka superior articular process) -Vertebral foramen: contains spinal cord, nerve roots, epidural space
Circulation of 2 posterior spinal arteries
-Aorta - subclavian - vertebral - posterior spinal -Aorta - segmental - posterior radicular - posterior spinal
Classic problem in Ehlers-Danlos
-Arterial aneurysm and increased bleeding tendency d/t poor vessel integrity (NOT coagulopathy) -Common complication is pneumothorax
Patients with myotonic dystrophy are at risk for...
-Aspiration -Respiratory muscle weakness -Cardiomyopathy and dysrhythmias -Sensitivity to anesthetics *Safe to administer halogenated anesthetics, NOT at an increased risk of MH
Paget's disease definition -Cause
-Associated with excess osteoblastic and osteoclastic activity that causes abnormally thick, but weak, bone deposits -Caused by excessive parathyroid hormone or calcitonin deficiency -No vascular involvement
Most common airway complication of RA? -Why -Risks -Surgical correction
-Atlantoaxial subluxation and separation of the atlanto-odontoid articulation -D/t weakening of the transverse axial ligament -Risk of spinal cord and vertebral artery compression with quadriparesis or paralysis -Surgical correction entails odontoid decompression and posterior cervical fusion *AO instability allows odontoid to directly compress the spinal cord at the level of the foramen magnum
Systemic lupus erythematosus definition
-Autoimmune disease characterized by the proliferation of antinuclear antibodies -Targets young women (1:1000)
Rheumatoid arthritis definition and pathophysiology
-Autoimmune disease that targets the synovial joints -Widespread systemic involvement d/t infiltration of immune complexes into small and medium arteries leading to vasculitis -Cytokines (TNF and interleukin-1) play a role
What order are fibers blocked in? (motor, autonomic, sensory) *Different types of nerves have different sensitivities to LA blockade
-Autonomic fibers - blocked 1st (blocks 2-6 dermatomes higher than sensory block) -Sensory fibers - blocked 2nd (blocks 2 dermatomes higher than motor block) -Motor neurons - blocked 3rd
Considerations for Ehlers-Danlos
-Avoid regional and IM injections d/t bleeding risk *Excessive bleeding can occur with invasive line placement or trauma during airway management
Where is the axon hillock located? What does the axon do?
-Between soma and axon of a neuron -Sends signals
Why is a difficult airway a contraindication for neuraxial anesthesia?
-Block failure may require rapid conversion to GA -Depression of reticular activating system is common and may contribute to sedation. IV sedatives may lead to airway obstruction or collapse
How does neuraxial anesthesia cause bradycardia? (3)
-Blockade of the pregang. cardioaccelerator fibers at T1-T4 (this promotes a relative inc. of parasympathetic tone) (B fibers) - unloading of ventricular mechanoreceptors (Bezold-Jarisch reflex) - unloading of stretch receptors in the SA node
Epidural hematoma definition -Compresses what -Causes -Treatment
-Blood that accumulates between the dura and bone which compresses the dura and can compress the spinal cord -Causes spinal cord ischemia and permanent neurological dysfunction -Surgical decompression within 8 hours proves the best chances of recovery
Unique finding in osteogenesis imperfecta
-Blue sclera -Sclere is also susceptible to fracture
Upper extremity complications with prone position and scoliosis
-Brachial plexus injury -Ulnar nerve injury
Classic problem in osteogenesis imperfecta
-Brittle bones -Fractures may occur during NIBP inflation or following fasciculations with succinylcholine -Risk of C-spine fracture and reduced cervical ROM during airway management
4 Methods to reduce ICP (general concepts)
-CBV reduction -CSF reduction -Cerebral edema reduction -Cerebral mass reduction (tumor debulking or hematoma evacuation)
Continuous interscalene block:
-Catheter is postioned near trunks of BP between scalene muscles -Catheter inserted 3-5cm beyond tip of block needle -Following initial bolus, rate of 5ml/hr is infused
Amyotrophic Lateral Sclerosis (ALS) Definition
-Causes progressive degeneration of motor neurons in the corticospinal tract -Astrocytic gliosis replaces the affected motor neurons -Etiology is unknown
The brain can be divided into 4 areas:
-Cerebral hemispheres -Diencephalon -Brainstem -Cerebellum
Anesthetic considerations with scoliosis -Cervical scoliosis -NO2 -Thoracic correction -Blood loss -Temperature regulation
-Cervical scoliosis: may have difficult intubation -NO2 increases PVR -Thoracic correction higher than T8 may require one lung ventilation -Prepare for significant blood loss: IVs, type and cross, autologous donation, cell saver -Use active warming: forced air warmer, fluids
Contraindications to neuraxial anesthesia (11)
-Coagulopathy -Increased intracranial pressure (increased chance of brain herniation with sudden change in CSF pressure) -Sepsis (Introducing infection across BBB, worsening HoTN) -Infection at puncture site (Infection across BBB) -Hypovolemia (worsening HoTN) -Valve lesions with fixed stroke volume (AS, MS, hypertrophic cardiomyopathy) -Scoliosis/Arthritis/Spinal fusion/osteoporosis (more difficult) -Difficult airway -Full stomach (HoTN may cause nausea and vomiting) -Peripheral neuropathy -Multiple Sclerosis (epidural is safe but an intrathecal technique may exacerbate symptoms. Real world ok, NCE contraindication)
The femoral block is the most ________ lower extremity block. It does not provide_______ ______ for surgical anesthesia. Which block can it be combined with to provide a complete block?
-Common -Does not provide sufficient coverage -Sciatic block for complete LE surgical coverage
Filum terminale definition
-Continuation of the pia mater caudal to the conus medullaris. Anchors the spinal cord to the coccyx -Internal portion extends from the conus medullaris to the dural sac, external portion extends from the dural sac to the sacrum
Treatment of MS -What needs to be avoided
-Corticosteroids, interferon, and azathioprine -S/Sx can be exacerbated by stress and increased body temperature (as small as 1*C) -Succinylcholine can cause life-threatening hyperkalemia
What are the boundaries of the epidural space? -Cranial border -Caudal border -Anterior border -Lateral border -Posterior borders
-Cranial border: foramen magnum -Caudal border: sacrococcygeal ligament -Anterior border : posterior longitudinal ligament -Lateral border: vertebral pedicles -Posterior borders: ligamentum flavum and vertebral lamina *epidural space is shallow anteriorly, but deeper posteriorly, esp. in lumbar region
Anesthetic considerations for SLE -Cricoarytenoid arthritis -Antiphospholipid antibodies -Cyclophosphamide
-Cricoarytenoid arthritis increases risk of postextubation laryngeal swelling and airway obstruction (treat with steroids and consider smaller ETT -Antiphospholipid antibodies may develop (prone to hypercoagulability and thrombus even with prolonged aPTT - stroke, DVT, PE) -Cyclophosphamide inhibits plasma cholinesterase and increases duration of succs -Pregnancy, stress, infection, and surgery can exacerbate s/sx
Airway complications of SLE
-Cricoarytenoiditis (hoarseness, stridor, airway obstruction) -Recurrent laryngeal nerve palsy
Cerebrospinal fluid functions (3)
-Cushions the brain -Provides buoyancy -Delivers optimal conditions for neurologic function
Anesthetic considerations with cricoarytenoid arthritis
-Decreased glottic diameter may increased the difficulty of passing an ETT -Use smaller ETT to minimize laryngeal trauma -Patient at risk of postextubation airway obstruction
Cardiac Considerations w/ DMD patients
-Degeneration of cardiac muscle: ↓contractility, papillary muscle dysfxn, Mitral regurg, cardiomyopathy, CHF -s/s of cardiomyopathy: tachycardia, JVD, S3/S4 gallop, displacement of point of maximal impulse -gold standard for evaluation is echo, can also do cardiac MRI
Multiple Sclerosis Definition -Symptoms -Cranial nerve involvement
-Demyelinating disease of the CNS -Patients experience sensory and motor deficiencies as well as autonomic instability -Cranial nerve involvement causes bulbar muscle dysfunction (aspiration risk)
Describe the site of action for epidural anesthesia -1st diffuse through __ -LAs also leak through __ to enter __
-Epidural space -LAs must 1st diffuse through dural cuff before they can block the nerve roots -LAs also leak through the intervertebral foramen to enter the paravertebral area - here, LAs can cause multiple paravertebral blocks
Epidural space communicates with the paravertebral space by way of ____ foramina -Epidural fat is a sink for lipophilic drugs (__>__>__)
-Epidural space communicates with the paravertebral space by way of the intervertebral foramina -Epidural space contains nerve roots, fat pads, and blood vessels. Epidural fat acts as a sink for lipophilic drugs, reducing bioavailability (bupivacaine> lidocaine and fentanyl> morphine) (Bupivacaine is more lipophilic and has decreased bioavailability; thus, you can give an increased dose)
Scleroderma Definition
-Excessive fibrosis in the skin and organs, particular in the microvasculature
How do spinal nerves exit the vertebral column?
-Exit via the intervertebral foramina
Components of cryoprecipitate
-Factor VI -Fibrinogen -Factor XIII -Fibronectin -Von-Willebrand Factor -80 uL of Factor VII/unit >150 mg/dL fibrinogen
Herniation of the temporal uncus results in what sign?
-Fixed and dilated pupil d/t compression and ischemia of the oculomotor nerve (CN III) -Oculomotor nerve originates from the midbrain and crosses near the tentorium
S/sx of anterior spinal artery syndrome
-Flaccid paralysis of lower extremities -Bowel and bladder dysfunction -Loss of temperature and pain sensation -*Preserved touch and proprioception (because the anterior circulation does not perfuse the dorsal column)
What are the 4 lobes of each cerebral hemisphere -What do they contain?
-Frontal - contains motor cortex -Parietal - contains somatic sensory cortex -Occipital - contains vision cortex -Temporal - contains auditory cortex and speech centers
Drug-induced lupus -Length of exacerbation -Symptoms
-Generally persists for several weeks to months -Mild symptoms of arthralgia, anemia, leukopenia, and fever
Positioning ways to increase venous outflow?
-Head elevation >30 degrees (head down increases CBV and ICP_ -Neck neutral (neck flexion or extension can compress the jugular veins, reduce venous outflow, increase CBV and increase ICP)
What are the respiratory effects of neuraxial anesthesia? -Healthy patients -Accessory muscles (intercostals, abd muscles)
-Healthy patients: negligible effects -Accessory muscle function is reduced which decreases pulmonary reserve (very important with COPD) - impaired intercostals (insp+exp) - impaired abd muscles (cough+clr)
Brain herniation tends to occur at 4 different locations:
-Herniation of the cingulate gyrus over the falx -Herniation of contents over the tentorium cerebelli (transtentorial herniation) -Herniation of the cerebellar tonsils through the foramen magnum -Herniation of contents through a site of surgery or trauma
Cricoarytenoid arthritis presents with...
-Hoarseness, stridor, dyspnea, edema/erythema of the vocal cords -May result in airway obstruction
How can you decrease cerebral blood flow? (4 broad)
-Hyperventilation (PaCO2 30-35mmHg constricts cerebral vessels→↑ cerebral vascular resistance →↓CBF →↓ICP ) -Avoid Hypoxemia (PaO2 <50-60mmHg increases CBF and ICP) -Drugs (Avoid cerebral vasodilators like nitroglycerine, nitroprusside; administer drugs to reduce CMRO2 (considered cerebral vasoconstrictors) like thiopental, propofol) -Hemodynamics (avoid extreme HTN which would cause cerebral edema)
How to measure the Cobb angle
-Identify the 2 most displaced vertebrae (top and bottom) -Line drawn parallel to each -Perpendicular line drawn from each of these lines -Angle where they intersect is the Cobb angle
How can mannitol increase cerebral edema? ICP?
-If BBB disrupted, mannitol enters brain and increases cerebral edema -Mannitol transiently increases blood volume which can increase ICP and stress a failing heart
Patho of neurogenic shock Hint: HR, inotropy, CO/BP, body temp
-Impairment of cardioaccelerator fibers (T1-T4) = bradycardia and decreased inotropy d/t unopposed cardiac vagal tone -Decreased SNS tone = vasodilation, venous pooling and decreased CO/BP -Sympathetic impairment from hypothalamus to blood vessels which inhibits vasoconstriction or shivering = hypothermia *Hypothermia is the result of the inability of cutaneous vasculature to vasoconstrict which redistributes blood flow to the periphery causing heat to escape
MOA of disease-modifying antirheumatic drugs
-Improve symptoms by inhibiting tumor necrosis factor (TNF), interleukin-1 and -6, and inhibit T cells and B lymphocytes *These drugs suppress the immune system and increase risk of infection and cancer
Why does autonomic hyperreflexia occur?
-In chronic phase of SCI, sympathetic reflexes below level of injury return; however, they return in a hyperactive state because inhibitory influences from above the level of injury are severed
Causes of increased CSF
-Increased CSF production by choroid plexus -Reduced CSF removal by arachnoid villi -Obstruction of reabsorption (bleed, infection, tumor) -Passage of fluid across the BBB
Abdomen complications with prone position and scoliosis
-Increased abdominal pressure --transmitted to veins that drain spine - > back bleeding (no valves) --Reduced pulmonary compliance (Jackson frame is better than Wilson frame)
Increased intrathoracic pressure increases/decreases venous outflow? -How an you decrease intrathoracic pressure?
-Increased intrathoracic pressure decreases venous outflow -Avoid PEEP, bucking, coughing, straining to decrease intrathoracic pressure -Increases intrathoracic pressure, and reduces venous drainage from brain
A subset of neurons in the corticospinal tract exert excitatory/inhibitory influence on lower motor neurons. -Significance?
-Inhibitory influence over lower motor neurons -Prevents lower motor neurons from firing too frequently
Eye complications with prone position and scoliosis
-Ischemic optic neuropathy d/t hypoperfusion and/or increased venous pressure -Corneal abrasion
Conditions that impair venous drainage
-Jugular compression with improper head positioning -Increased intrathoracic pressure secondary to coughing or PEEP -Vena cava thrombosis -Vena cava syndrome - blocked superior vena cava
Respiratory Considerations w/ DMD patients
-Kyphoscoliosis (restrictive lung disease) -> ↓pulmonary reserve -> ↑secretions & risk for pneumonia -Respiratory muscle weakness
Pulmonary considerations of osteogenesis imperfecta
-Kyphoscoliosis and pectus excavatum reduce chest wall compliance and vital capacity, leading to VQ mismatch and hypoxemia
The corticospinal tract is made up of 2 tracts -What do they innervate?
-Lateral corticospinal tract: Limb fibers -Ventral corticospinal tract: Axial (head, neck and trunk) fibers
Technique for caudal anesthesia:
-Lateral(simms postions)/prone(frog leg and use a roll to support iliac crests) -use superior iliac crests for landmarks to find trianglular sacrum -Bevel up thru sacral hiatus aim cephalad -Needle tip beyond S2-S3 increases risk for dural puncture -Aspirate for blood/csf- do not use AIR for loss of resistance (may cause air embolism)
Anesthetic mgmt of parkinsons
-Levodopa half life 6-12 hours. Should be taken morning of surgery. Must be administered via OG for longer procedures -Antidopaminergic drugs are contraindicated (metaclopramide, haloperidol, droperidol, promethazine) -Anticholinergics can be used to treat exacerbations -No contraindication to NMB's -Do not use alfentanil or Ketamine
What drugs can be given to reduce cerebral edema? How? Hint: Diuretics and Corticosteroids
-Loop Diuretics: induce diuresis and decrease CSF production -Osmotic diuretics (Mannitol 0.25-1.0 g/kg): increases serum osmolarity and pulls water across BBB -High tonicity fluid (3% NaCL): pulls water across BBB -Dexamethasone/Methylprednisolone: reduce cerebral edema caused by mass lesions (also used with spinal cord injuries)
Effect on CBF -Metabolic acidosis -Respiratory acidosis -Respiratory alkalosis
-Metabolic acidosis : No effect (hydrogen does not pass through the BBB) -Respiratory acidosis: increases CBF -Respiratory alkalosis: decreased CBF
Examples of disease-modifying antirheumatic drugs and common side effects -Individual side effects of each med
-Methotrexate, cyclosporine, and etanercept -Methotrexate causes liver dysfunction and suppresses the bone marrow -Cyclosporine prolongs the duration of succinylcholine
S/Sx of RA
-Morning stiffness -Joints are painful, swollen, and warm -Weakness, fatigue, anorexia -Lymph node enlargement in cervical, axillary, and epitrochlear (upper arm) regions
Hallmark of RA
-Morning stiffness that generally improves with activity -Joints are painful, swollen, and warm
how to approach the interscalene block
-Most proximal approach to the brachial plexus -A paravertebral approach at the cervical roots in the neck -Relatively easy place to enter the brachial plexus sheath and elicit a parasthesia shallow block.
A-Alpha Fibers -Myelination -Function -Diameter -Conduction velocity -Block onset
-Myelination: heavy myelination -Function: skeletal muscle (motor), proprioception -Diameter: 12-20 -Conduction velocity: +++++ -Block onset: 4th Alpha male *heavy* liftin' Bulky *muscles* and *proprioception* *12-20* reps with a *5 star speed* Still *4th* place on my Tinder rotation
Treatment for neurogenic shock
-NE to restore SVR and inotropy -Volume expansion - over resuscitation may lead to myocardia dysfunction and pulmonary edema --Use an A line to determine the adequacy of both NE and volume expansion
Secondary s/sx of autonomic hyperreflexia
-Nasal stuffiness d/t vasodilation above the level of injury -Headache and blurred vision d/t hypertension -Stroke, seizure, LV failure, dysrhythmias, pulmonary edema, MI from malignant hypertension
How accurate is nerve stimulation?
-Nerve stimulator settings have no consistent relationship to proximity to the nerve and can be misleading. -Conditions such as the neuropathy associated with diabetes can render the nerve stimulator almost worthless. -Poor return electrode placement and inconsistent contact in the active electrode can further muddy the issues.
How does neuraxial anesthesia affect the neuroendocrine response to stress? -Reduces circulating levels of...
-Neuraxial anesthesia diminishes surgical stress response by inhibiting afferent traffic originating from surgical site -This reduces circulating levels of: catecholamines, renin, angiotensin, glucose, thyroid stimulating hormone, growth hormone
Differential blockade Epidural Anesthesia -Autonomic differential blockade -Sensory block
-No autonomic differential blockade with epidural anesthesia -Sensory block is 2-4 dermatomes higher than motor block *Not likely to drop BP
Paralytic choice for patients with ALS
-No succinylcholine: can cause lethal hyperkalemia d/t lower motor neuron proliferation of postjunctional nicotinic receptors -Increased sensitivity to nondepolarizing NMB
Anesthetic considerations for ALS
-No support of any particular anesthetic technique -Increased risk of aspiration (bulbar muscle dysfunction) -Chest weakness reduces vital capacity and maximal minute ventilation -May need postop mechanical ventilation
Can you use succinylcholine in patients with Gullian-Barre? Is GB sensitive to non depolarizers?
-No- avoid succs- risk of hyperK+ from proliferation of extrajunctional Ach receptors -Yes increased sensitivity to NDNMB
Block onset order -Block regression order
-Onset: B, C, A delta and gamma, A alpha and beta (pre-ganglionic sympathetic, temp, pin prick (fast pain), touch. motor) -Regression is in opposite order of onset
Most common problems with Paget's disease
-Pain and fractures -Peripheral nerve entrapment may occur
Why is peripheral neuropathy a contraindication for neuraxial anesthesia?
-Patients more susceptible to injury, slower to recover *More of a legal thing than scientific thing
Cranial nerves are part of the central or peripheral nervous system? -Which one is the exception?
-Peripheral nervous system -Optic Nerve (II) is part of the central nervous system and is surrounded by dura
Median Nerve: SENSORY test MOTOR test
-Pinch index finger -Thumb opposition
Musculocutaneous Nerve: SENSORY test MOTOR test
-Pinch lateral asepct of forearm -Elbow flexion (biceps contraction)
Axillary Nerve: SENSORY test MOTOR test
-Pinch lateral aspect of shoulder -Arm abduction (deltoid contraction)
Ulnar Nerve SENSORY test MOTOR test
-Pinch pinky finger -Pinky finger ABDuction
Radial Nerve: SENSORY test MOTOR test
-Pinch web space between thumb and index finger -Elbow extension (triceps contraction) Wrist + finger extension Radial REACTS to thumb (sensory) Medial Movement of thumb (motor)
Neuraxial Anesthesia Contraindications: Coagulopathy -Platelet count -PT, aPTT, bleeding time -Why?
-Platelet count < 100,000 -Pt, aPTT, and/or bleeding time 2x normal value -risk of spinal or epidural hematoma
Most common problems of SLE
-Polyarthritis and dermatitis -Arthritis can affect any joint, but generally does not involve the spine
When are somatosensory evoked potentials (SSEP) used? -Motor or sensory function? -Can you use NMB?
-Posterior cord (dorsal column pathway) -Posterior spinal arteries -Sensory function -SSEPs do NOT monitor motor function -NMB do not interfere with SSEP monitoring
Lower extremity complications with prone position and scoliosis
-Pressure on iliac crest -> lateral femoral cutaneous nerve injury -Pressure latera to fibula -> peroneal nerve injury -Hip flexion -> femoral vein occlusion -> DVT
What produces CSF and where is it located?
-Produced by ependymal cells of choroid plexus. -Choroid plexus is located in all 4 cerebral ventricles
Myotonic dystrophy -Definition -Physiology
-Prolonged contracture after a voluntary contraction -Result of dysfunctional calcium sequestration by the SR -Contractions can be so severe they interfere with ventilation and intubation
RA vs osteoarthristis
-RA: affects proximal interphalangeal and metacarpophalangeal joints in the hands and feet with systemic involvement -Osteoarthritis: affects weight bearing joints and no systemic involvement
Increased pulmonary vascular resistance with scoliosis causes what? -EKG
-RV hypertrophy -EKG: RV strain and RA enlargement
Astrocytes function
-Regulation of metabolic environment -Repair neuron after neuronal injury
Thalamus functions
-Relay station that directs information to various cortical structures and regulates consciousness and alertness (the reticular activating system ascending projects to the thalamus)
HTN best treated with... (3) -What type of med should you avoid?
-Removal of stimulus -Deepening anesthetic -Rapid acting vasodilator (sodium nitroprusside) -administration of a positive chronotrope with vasoconstrictive properties will worsen HTN
Pulmonary complications of SLE
-Restrictive ventilatory defect -Pulmonary HTN -Interstitial lung disease with impaired diffusing capacity -Pleural effusion -Recurrent pulmonary emboli
Early respiratory complications with scoliosis
-Restrictive ventilatory defect: decreased FEV1 and FRC but normal ratio -Decreased VC, TLC, RV, FRC, and chest wall compliance *Scoliosis alters thoracic geometry which compresses the lungs and creates a restrictive ventilatory defect. One side of the thorax becomes smaller.
Most common offenders of exacerbation of SLE
-Result from stress or drug exposure PISSED CHIMP Pregnancy, Infection, Surgery, Stress, Enalapril, D-penicillamine Captopril, Hydralazine, Isoniazid, Methyldopa, Procainamide
Laboratory findings in RA
-Rheumatoid factor (anti-immunoglobulin antibody) increased in 90% of patients with RA -C-reactive protein is increased -Erythrocyte sedimentation rate is increased
Where are ependymal cells located?
-Roof of the 3rd and 4th ventricles and spinal canal *Involved in CSF production
What does the blood brain barrier separate? What restricts passage of large molecules and ions within the BBB?
-Separates CSF from plasma -Tight junctions restrict passage of large molecules and ions (does not have carrier proteins)
EKG changes in Duchenne
-Sinus tach and short PR interval -Increased R amplitude in lead 1 -->scarring of posterobasal (back/bottom) aspect of LV) -Deep Q waves in limb leads
List all 13 structures and spaces between the skin and the spinal cord as they would be encountered during a subarachnoid block
-Skin -SubQ -Muscle -Supraspinous ligament -Interspinous ligament -Ligamentum flavum -(EPIDURAL SPACE) -Dura mater: tough fibrous protective shield that protects spinal cord, begins at foramen magnum and ends at dural sac -(SUBDURAL SPACE) -Arachnoid mater: thin connective tissue layer -(SUBARACHNOID SPACE - contains CSF, nerve roots, rootlets and spinal cord; target for spinal) -Pia mater: external covering of spinal cord, should NEVER be punctured during spinal anesthesia -Spinal cord DAPS: Dura, arachnoid, pia, spinal cord
What are watershed areas in the spine? What are they vulnerable to?
-Some regions of the cord only have a single blood supply -Vulnerable to ischemia * important to know the spinal cord is perfused in segments, not the entire length of the cord
Telangiectasia definition -Significance
-Spider veins -Increase the risk of mucosal bleeding, particularly during nasal intubation
Common events that cause autonomic hyperreflexia
-Stimulation of hollow organs (bladder, bowel, uterus) -Bladder catheterization -Surgery, especially cysto or colonoscopy -Bowel movement -Cutaneous stimulation -Childbirth
Describe the site of action for spinal anesthesia -Primary site of LA action
-Subarachnoid space -Primary site of LA action = myelinated preganglionic fibers of the spinal nerve roots LAs also inhibit neural transmission in the superficial layers of the spinal cord
3 things that increase the risk of contractors with myotonic dystrophy
-Succinylcholine (use nondepolarizer) -NMB reversal with anticholinesterases (use sugammadex instead) -Hypothermia (shivering -> sustained contractions)
Answer
-Supraspinous ligament: runs most of the length of the spine and joins the tips of the spinous processes -Interspinous ligament: travels adjacent to an joins the spinous processes -Ligamentum flavum -Posterior longitudinal ligament: travels along the posterior surface of the vertebral bodies -Anterior longitudinal ligament: attaches to the anterior surface of the vertebral bodies and extends the entire length of the spine. Also attaches to the annulus fibrosis of the intervertebral discs
SCI with neurogenic shock definition -symptoms
-Sympathectomy below the level of the injury -Hypotension, bradycardia, and hypothermia (Extremities will be warm and pink d/t vasodilation)
Where do you place a catheter for a ___ surgery -Thoracic -Upper abdominal -Middle abdominal -Lower abdominal -Lower extremity
-T4-8: Thoracic -T6-8: Upper abdominal -T7-10: Middle abdominal -T8-T11: Lower abdominal -L1-4: Lower extremity
Rheumatoid arthritis impacts the airway in 3 places:
-Temperomandibular joint (synovitis of TMJ can limit mouth opening) -Cricoarytenoid joints (decreased diameter of glottic opening) -Cervical spine (atlanto-occipital subluxation with flexion, limited extension)
What does chronic HTN do to autoregulation?
-Textbook: shifts the curve to the right (more tolerant of HTN, less tolerant of HoTN) -Reality: plateau of curve narrows and CBF is more dependent on CPP (high patient to patient variability)
Risks of wake up test
-Tracheal extubation -Removal of intravenous or arterial lines -Air embolism -Awareness -Pain -Damage to surgical instrumentation
CREST syndrome definition -S/Sx
-Type of scleroderma -Calcinosis, Raynaud's, Esophageal hypomotility, Sclerodactyly, Telangiectasia
Needles used in peripheral nerve blocks?
-Typical 22 g insulated block needles can be used. -Alternatively, 18 g Touhy needles sometimes are used, because are easier visualized, or for catheter placement.
Airway complications with prone position and scoliosis
-Upper airway edema - consider leak test -ETT kink or inadvertent extubation
What is inverse steal or the Robinhood effect? -Draw backs -Best practice
-Using hyperventilation to constrict cerebral vessels and redistribute flow to ischemic areas -Not shown to have a clinical benefit, can shift oxyhemoglobin curve to left, and reduce CBF -Maintain normocapnia or mild hypocapnia 30-35 mmHg
Cerebrospinal fluid locations (3)
-Ventricles (left lateral, right lateral, third, and fourth) -Cisterns around the brain -Subarachnoid space in brain and spinal cord
What are the anatomical boarders of the intervertebral foamina?
-Vertebral body and intervertebral disc form anterior boarder -Facet joints form posterior boarder
What occurs when CPP is greater than 150?
-Vessels are maximally constricted (also with PaCO2 of 25mmhg) -CBF becomes pressure dependent on MAP -Risk of cerebral edema and hemorrhage
What occurs when CPP is less than 50?
-Vessels are maximally dilated (also with PaCO2 80-100) -CBF becomes pressure dependent on MAP -Risk of cerebral hypoperfusion and ischemia
What is a wake up test and why is it used?
-Wake up test assesses neurologic integrity during spine surgery to avoid neurologic injury (paraplegia) -Abandoned in favor of SSEP/MEP monitoring but can still be used if these monitors fail
Cerebral Steal Phenomena
-When cerebral vasodilation (hypercapnia, hypoventilation, vasodilators) causes blood to go to healthy tissue and steal flow from ischemic areas -Healthy brain tissue has tone and diameter is based on PaCO2 -Ischemic or atherosclerotic tissue is maximally dilated
Cervical and thoracic spinous processes angle in a ___ direction -More ___ approach with a needle
-caudal direction -cephalad needle approach
Deliberate HoTN to maintain MAP 60mmHg increases risk of ___ and ___ -What should you monitor?
-cerebral hypoperfusion and ischemic optic neuropathy -Monitor end organ perfusion with serial ABG (metabolic acidosis) and urine output
Second order neuron (Dorsal)
-crosses to contralateral side in the medulla, then ascends to the thalamus via the medial lemniscus -joined by the trigeminal nerve which provides sensation to the head -synapses with the 3rd order neuron in the thalamus - ventrobasal complex
Cerebral vasospasm
-delayed contraction of cerebral arteries -can lead to cerebral infarction -can be caused with free hgb in contact with outside of cerebral arteries (ie. blood where its not supposed to be) -most common 4-9 days following SAH
Terminal end of subarachnoid space is called__ Coincides with __ in adults and __ in infants
-dural sac -S2 adults -S3 infants
The diagnosis of AO subluxation is made when the distance between the anterior arch of the atlas and the odontoid process is... -How is this best assessed?
-greater than 3mm -Best assessed with a lateral x-ray of the cervical spine
Pruiritis
-more common in obstetric patients -caused by opioid receptors in the trigeminal nucleus (NOT mast cell degranulation) -treat w/ naloxone (benadryl will not treat this, but the sedative effect may be helpful)
Lumbar spinous process projects in a ___ direction
-posterior direction -Epidurals and intrathecal spaces easier to access
Vertebra are separated by intervertebral discs that act as ___. -Disc degeneration
-shock absorbers -Disc degeneration reduces the size of intervertebral foramina and can cause nerve compression
Upper extremity nerve blocks:
1)Brachial plexus: -Interscalene, Supraclavicular, -Infraclavicular, Axillary 2)Individual nerve blocks: -Usually to supplement brachial plexus block 3)IV regional block (bier block) 4)Other Misc. blocks 5)N.A.V.E.L.- nerve (most lateral), artery, vein, empty space, lymphatics (most medial
Rank the speed of LA uptake after injection into the following sites: (1 fastest, 4 slowest) Intrapleural, caudal, brachial plexus, intercostal
1)Intrapleural 2)Intercostal 3)Caudal 4)Brachial plexus
Technique for interscalene block
1)Standard monitors 2)Crash Cart 3)Pt. supine head to contra lateral side 4)Sterile prep/drape 5)Localize skin @ level of cricoid cartilage 6)22g. 1 ½ in. needle inserted *45-70 degree angle* perpendicular and advanced in a caudal direction. 7)Very shallow Block , May feel a pop. Once parasthesia is obtained, the needle is stabilized and after negative aspiration for blood, 20 to 40 cc's of the local anesthetic solution is injected slowly and carefully.
CSF pressure
5-15 mmHg
What 2 factors increase the risk of CES?
1. 5% Lidocaine 2. Micro catheters (focus LA on a small area of the SC, exposing region to high conc. of LA)
The risk of MH is NOT increased with what syndromes?
1. Becker muscular dystrophy 2. Neuroleptic malignant syndrome 3. Myotonia congenita 4. Myotonic Dystrophy *may see this on the exam
What are the 5 determinants of blood flow?
1. Cerebral metabolic rate for oxygen 2. Cerebral perfusion pressure 3. Venous Pressure 4. PaCO2 5. PaO2
MH treatment acute phase
1. D/C triggering agent 2. Call for help, tell surgeon to end procedure 3. Hyperventilate pt w/ 100% O2, 10L/min (don't waste time changing soda lime) -Facilitates CO2 elimination -↑ O2 delivery -drives K+ into cells 4. Administer Dantrolene 5. Cool pt 6. Correct lactic acidosis (bicarb) 7. Treat hyperkalemia 8. Class I antiarrhythmics 9. Maintain UOP > 2ml/kg/h (mannitol, lasix, fluid) 10. Monitor coag panels for DIC (Late sign)
Steps of treating an MH episode
1. D/c triggering agent and call for help and tell surgeon to stop 2. Hyperventilate with 100% O2 at 10L/min (Drives K+ into cells, CO2 elimination, O2 delivery) 3. Administer Dantrolene 4. Cool patient until temperature drops below 38 5. Correct lactic acidosis 6. Treat hyperkalemia 7. Protect against dysrhythmias 8. Maintain UOP >2ml/kg/hr 9. Check coag panals- DIC is late complication and signals impending death
Bier Block: 20 - 40 min since LA injection. Can you deflate cuff?
1. Deflate 2. Immediately reinflate 3. Deflate again at 1 minute
Post spinal Bacterial meningitis: What are the 2 ways infection can reach the CSF? What is the most common culprit?
1. Failure of aseptic technique 2.Bacteria in pt's blood at time of SAB Streptococcus viridans- most commonly found in the mouth- wear a mask. Also on hands and arms
Relative contraindications d/t HoTN caused by sympthectomy
1. Fixed valve lesions = severe AS, MS, hypertrophic cardiomyopathy 2. Full stomach can lead to N/V d/t HoTN
How do you prepare for patient at risk for MH?
1. Flush anesthesia machine with hiflo O2- 20-100min 2. Remove and replace CO2 absorbent, circuit, bag 3. physically remove vaporizers from the machine - if pt doesnt present with s/sx of MH w/in 1st hr- very unlikely to occur -pt needs to be monitored in PACU for 1-4h before dc home
What are the 2 reasons why an epidural blood patch works?
1. Increases CSF pressure by compressing epidural and subarachnoid spaces 2. Acts as a plug to prevent further leaks
Conditions w/ a link to MH
1. King Denborough syndrome 2. Central core disease 3. Multiminicore disease possible link w/ hypokalemic periodic paraylysis
What 4 factors increase the risk for TNS?
1. Lidocaine 2. Lithotomy 3. Ambulatory surgery 4. Knee arthroscopy
The *lateral femoral cutaneous n.* MOTOR innervation: SENSORY innervation:
1. None 2. Lateral thigh
Order for bier block tourniquet inflation
1. PIV in operative arm 2. elevate arm for 2 minutes 3. wrap w/ esmarch 4. Inflate distal cuff 5. Inflate proximal cuff 6. Deflate distal cuff 7. Remove esmarch 8. Inject LA
What are the 5 RELATIVE contraindications to caudal anesthesia?
1. Pilonidal cyst 2. Abnormal superficial landmarks 3. Hydrocephalus 4. Intracranial tumor 5. Progressive degenerative neuropathy
Bier block procedure steps:
1. Place double cuff tourniquet on (not inflated) 2.Place 22g PIV in hand of operative site 3.elevate arm for 1-2min to allow passive exsanguination 4. tightly wrap esmarch band around arm to further exsanguinate until reach distal cuff 5. Inflate distal cuff first (helps exsanguinate further 6. inflate proximal cuff (deflate distal if you want LA to anesthetize under distal so it can be switched if torniquet pain starts happening) 7. remove esmarch 8. inject LA (usually 40-50ml 0.5% lido) 9. remove 22g PIV for surgery if it is in the surgical field (can be left in if redosing is anticipated)
What 2 features of the Tuohy needle help prevent dural puncture?
1. Pronounced curvature (30 deg) 2. Blunt tip
The big 4 side effect of neuraxial opioids
1. Pruitis 2. Respiratory depression 3. Urinary retention 4. N/V
1. Opioid in intrathecal space easily diffuses into ______ 2.opioid in epidural space diffuses into____
1. spinal cord 2. epidural tissue-->dural cuff--> CSF--->spinal cord (some also diffuses into the bloodstream so need a higher dose to reach the subarachnoid space)
Characteristics of lipophilic opioids
1. stays in CSF for a shorter period of time 2. minimal rostral spread -> narrower band of analgesia 3. Site of action: Substantia gelatinosa Rexed Lamina II & III & systemic 4. Onset is fast (5-10min) 5. Duration is shorter (2-4h) 6. more systemic absorption 7. Early (<6h) respiratory effects only 8. Low incidence of N/V & Pruritis
Characteristics of hydophilic opioids
1. stays in CSF longer 2. More extensive spread -> wide band of analgesia -> more rostral spread (toward brain) 3. Site of action: Substantia gelatinosa Rexed Lamina II & III 4. Onset is delayed (30-60min) 5. Duration is longer (6-24h) 6. Less systemic absorption 7. Early (<6h) and Late (>6h) respiratory effects 8. High incidence of N/V & Pruritis
Specific gravity of CSF
1.002 - 1.009
What is the specific gravity of CSF?
1.002 - 1.009
Specific gravity of CSF
1.002-1.009
Normal ICP
5-15 mmHg gold standard monitor is an intraventricular catheter
Most common culprits of Guillain-Barre: (3) Other causes:(3)
1.Campylobacter jejuni 2. Epstein-Barr (mono) 3. cytomegalovirus (CMV) Other: vaccinations, surgery, lymphomatous disease
Dantrolene MOA
1.Halts Ca release from the RyR1 receptor 2.Prevents Ca entry into the myocyte, reducing the stimulus for calcium-induced calcium release
The *posterior femoral cutaneous n.* MOTOR innervation: SENSORY innervation:
1.None 2. Posterior thigh
Why is a caudal block more for pediatrics?
1.Sacral anatomy is hard to ID in adults 2.Lumbar approach to epidural space is easier and equally effective in adolescence and adults
Pruritus caused by opioids: 1.Most common ___ ___ of neuraxial opioids, which patient population is it most common with? 2. what causes it? 3. How do you treat it?
1.Side effect; Obstetric patients 2. Caused by opioid stimulation of opioid receptors in trigeminal nucleus, NOT mast cell degranulation (non histamine releasing opioids can cause it- fent/sufenta) 3. opioid antagonist naloxone (benadryl doesnt fix it)
What other complications are associated with supraclavicular block? (2)
1.Stellate ganglion/horners syndrome- LA can spread proximal towards sympathetic chain on anterior vertebral body 2. LA injection into the subclavian artery
The anterolateral system transmits sensory info ___ to ___ as fast as the dorsal column (medial leminiscal)
1/2- 1/3 as fast central will be faster than lateral
Meperidine Intrathecal dose: Epidural dose: Epidural infusion dose:
10 mg 25-50mg 10-60mg/hr *Similar to sufentanil
Exception to baricity rule
10% procaine in water is hyperbaric b/c of the number of molecules in a 10% solution
Therapeutic level of phenytoin
10-20mcg/mL
How much blood is withdrawn for an epidural blood patch
10-20ml When the patient senses pressure in her legs, buttocks or back the injection is complete
What is the average amount of irrigation that is systemically absorbed during TURP?
10-30mL/min Blood loss = 2-5mL/min
Cobb angle associated with significantly impaired gas exchange and high risk for postop pulmonary complications
100 degrees
Convert 38.3C to farenheight
100.9 F = (C x 1.8) + 32
CSF pressure
5-15mmHg
After Bier block, case is completed in 10 min after injection of LA. What is the additional time you must wait before you can safely deflate the tourniquet?
10min TQ must be inflated for a minimum of 20mins after youve injected the LA
Normal ICP
5-15mmHg
During an aneurysm repair, SBP should be between....
120-150mmHg
Percentage of cardiac output going to global cerebral blood flow
15%
According to SCIP, vancomycin must be started within ___min of surgical incision
120min. all abx must be started within 1hr, vanco is the only exception
percent of cardiac output that goes to the brain
15%
To minimize the risk of intracranial hemorrhage during DBS, SBP should not exceed...
140mmHg
What is the angle of a Hustead needle?
15 degrees
CSF volume
150mL
At what level of CBF is there complete cortical suppression?
15mL/100g/min
Core temp may rise within ____min of exposure, but profound hyperthermia is a ______ sign
15min ; late sign
Hughstead epidural needle
15°
At what temperature does EEG suppression occur?
18-20°C
Where do motor neurons travel? (General both limb and axial muscles)
1: Exit the pre central gyrus in the frontal lobe of the cerebral cortex (upper motor neuron) 2: Pass through the internal capsule 3: Travel inferiorly through the pyramids of the medulla 4: Synapse in the ventral horn of the spinal cord to limb or axial muscles (lower motor neuron)
Autonomic Hyperreflexia pathway -Stimulation below level of spinal cord injury...
1: stimulation below level of spinal cord injury 2: activation of sympathetic nerves 3: Vasoconstriction below level of injury 4: HTN 5: Baroreceptor reflex stimulation in carotid sinus 6: Bradycardia and vasodilation above the level of injury *Sympathetic nerves below the level of injury do NOT receive inhibitory signals from brain and do NOT vasodilate when baroreceptor reflex is activated
Dantrolene infusion dose on ICU
1mg/kg q 6h or 0.1-0.3mg/kg/h for 48-72h
Dantrolene dose in ICU following MH episode
1mg/kg q6hr or 0.1-0.3mg/kg/hr for 48-72 hours
What is the minimum amount of LA injected into the vertebral artery that can cause seizures?
1ml
C6 innervation
1st digit, thumb
Match each neuron in the spinothalamic tract to the location where its cell body resides? 1st order neuron- 2nd order neuron- 3rd order neuron-
1st order neuron- dorsal root ganglion 2nd order neuron- dorsal horn 3rd order neuron- thalamus
Order of block
1st: Autonomic nerves (first) 2nd: Sensory fibers 3rd: Motor fibers (last) The highest level will be autonomic nerves (2-6 dermatomes higher than sensory) sensory will be blocked at a higher level than motor fibers (2 dermatomes higher than motor)
Spinal cord circulation consists of...
2 posterior spinal arteries 1 anterior spinal artery 6-8 radicular arteries
Which local anesthetic reduces the efficacy of epidural opioids?
2-chloroprocaine
Max dose of Ropivicaine for peripheral nerve block?
2.5 mg/kg or 250 mg
Potassium in CSF compared to plasma
2.8 in CSF vs. 4.5 in plasma
Minimum amount of time the tourniquet needs to stay inflated w/ a bier block?
20 minutes
Bier Block: What is the minimum amount of time that the TQ must remain inflated following injection of LA?
20 minutes - allows time for LA to absorb into tissue - if cuff deflated too soon, LA washes into systemic circulation, can result in sz or CV collapse
At what level of CBF is there evidence of ischemia?
20mL/100g/min
Subcortical CBF
20mL/100g/min
Each vial of dantrolene contains...
20mg of dantrolene and 3g of mannitol Must be reconstituted with 60mL preservative-free water 20 * 3 = 60
Spinal needle smaller than ___ gauge needs introducer In interspinous ligament to decrease risk of needle deflection
22
When to use an introducer
22g needle or smaller
When should succinylcholine be avoided after SCI?
24 hours after the injury -Fasciculations may worsen SCI -In general, pick a nondepolarizer over succs *Succinylcholine is contraindicated in patients with chronic SCI
Vision loss with ION typically occurs...
24-48 hours after surgery
To reduce the risk of rebleeding, surgical repair of a ruptured aneurysm should take place...
24-48 hours following the initial bleed (makes triple H therapy safer)
A drug has a Vd of 0.5L/kg. In an 85kg patient, what loading dose must be administered to achieve a plasma concentration of 6mg/l?
255mg Loading Dose = (Vd x desired Cp) / Bioavailability Loading Dose = (42.5L x 6mg/L) / 1 = 255mg Bioavailability = 1 since drug is being given IV
Maximal vasoconstriction occurs at a PaCO2 of...
25mmHg Decreased PaCO2 = Decreased CBF d/t vasoconstriction
Pulmonary hypertension is defined as PAP of at least?
25mmHg and a PAOP of no more than 15mmHg
With triple H therapy, what should Hct be reduced to?
27-32%
For every 1 inch above the heart, the real MAP is ___mmHg less than what you see on the monitor
2mmHg
C7 dermatome
2nd and 3rd digit
How many trunks in the brachial plexus and what are they?
3 Trunks: Superior Middle Inferior
How many *cords* are in the brachial plexus?
3 cords: - Posterior (C5-T1)- all posterior--> posterior cord - Lateral (C5-C7)- anterior divisions superior and middle trunk--> lateral cord - Medial (C8-T1)- anterior division of inferior trunk--> medial cord *Divisions turn into cords when brachial plexus goes under pectoralis minor muscle
Within how many hours of an ischemic stroke must TPA be given
3 hours
Optimal depth of catheter insertion
3 to 5 cm
How many *trunks* are in the brachial plexus? What are the corresponding nerve roots?
3 trunks: - Superior (C5-C6) - Middle (C7) - Inferior (C8-T1) *roots turn to trunks just beyond lateral border of scalene muscles
Tx for Eaton-Lambert
3, 4- diaminopyridine (DAP) Anticholinesterases do not help
Treatment of Eaton-Lambert syndrome
3,4-diaminopyridine (DAP) increases ACh release from the presynaptic nerve terminal and improves the strength of contraction **anticholinesterases are NOT helpful and the tensilon test does not dx)
Cerebral metabolic rate for oxygen (CMRO2) number
3-3.8mL/O2/100g/min -CBF is coupled to CMRO2: the higher the need for O2, the more blood flow there will be to satisfy this need
optimal depth of catheter insertion in the epidural space
3-5cm
Production rate of CSF
30mL/hr
Tuohy epidural needle
30° Blunt tip Minimize Risk of dural puncture
Spinal cord has how many paired spinal nerves?
31 paired spinal nerves -Each spinal nerve is formed by a posterior (dorsa) nerve root and anterior (ventral) nerve root. -Posterior nerve roots carry sensory information and anterior nerve roots carry motor and autonomic info
The vertebral column is made up of _____ vertebrae
33 7 cervical 12 thoracic 5 lumbar 5 sacral 4 coccygeal
Percentage of patients with SLE that develop the malar "butterfly" rash
33-50%
Protein in CSF vs. plasma
35 in CSF vs. 7000 in plasma
After the patient is stabilized in ICU, be aware that MH may reoccur up to how late?
36 hours later
Active cooling for the MH patient should stop when temp is below:
38c
Mallampati Score of hard palate only
4
How to do a digital nerve block:
4 small nerves innervate each digit -inject 2-3ml of LA at base of both sides of finger- caution arteries are close *NCE dont use epi for these blocks (real life some providers do)
Typical depth of cords
4-5cm
Seizure prophylaxis in the preeclamptic patient begins with magnesium loading dose of
4-6grams IV maintenance 1-g/hr IV target plasma concentration = 2-3.5mEq/L
When is cerebral vasospasm most likely?
4-9 days after SAH
Max does of Lidocaine for peripheral nerve block?
4.5mg/kg or 300 mg
Cobb angle that is indication for surgery
40-50
Cobb angle that indicates need for surgery
40-50 degrees
Hyperthermia beyond what temperature denatures proteins and destroys neurons?
42°C At this point, cerebral blood flow decreases
80kg patient for liposuction. What is the maximum recommended dose of lidocaine for tumescent anesthesia
4400mg
Bier Block: When does TQ pain onset typically begin?
45 - 60 minutes after inflation
Global cerebral blood flow
45-55mL/100g tissue/min
A continuous *femoral n.* block provides analgesia for how long?
48 hours
C8 dermatome
4th and 5th digit
How many *terminal branches* are in the brachial plexus?
5 terminal branches: - musculocutaneous - axillary - median - radial - ulnar
Dose for a bier block
50 mL of 0.5% lidocaine
What 2 changes in somatosensory evoked potential monitoring suggest an increased risk of nerve injury?
50% decrease in amplitude 10% INcrease in latency
At a PaCO2 of 40mmHg, CBF is...
50mL/100g/min
CRNA is using an anesthesia machine that couples fresh gas flow to the tidal volume set on the ventilator. What is the total tidal volume delivered to the patient? Oxygen= 2L/min Air flow= 1L/min Bellows set at 450mL RR = 10 I:E ratio is 1:2
550mL Convert FGF to mL/min = 3000mL/min Multiply FGF by fraction of inspiratory time: 3000 x (1/3) = 1000 Divide by RR: 1000 / 10 = 100mL Add to volume set on bellows
How many oxygen atoms are bound to one hgb molecule when the mixed venous oxygen saturation is 75%?
6
How many *divisions* are in the brachial plexus?
6 divisions: - 3 anterior - 3 posterior * each trunk turns into anterior and posterior division under clavicle and over 1st rib
MH can occur as late as...
6 hours after exposure to a triggering agent
Half life of levodopa
6-12 hours
Draw the brachial plexus
7 cervical vertebra but 8 cervical spinal nerves C8 refers to the nerve
How much does CMRO2 decrease per 1 degree celcius
7% = decreasing CMRO2 makes the brain more tolerant of decreased blood flow (more immune to ischemia) EEG suppression occurs at 18-20 degrees
Keep CPP >_______mmHg
70mmhg
Cortical CBF
75-80mL/100g/min
How soon must surgical decompression be performed for the best chance of recovery from an epidural hematoma?
8 hours
Specificity of the halothane contracture test
80% Risk of a false-negative result
Maximal vasodilation occurs at a PaCO2 of...
80-100mmHg Increased PaCO2 = Increased CBF d/t vasodilation
The grey matter is subdivided into how many laminae?
9
What is the success rate of an EPD blood patch?
90% *if HA does not improve after 2 patches, other etiologies should be sought
Babinski sign with damage to the lower motor neurons
Absent Babinski
Within how much time can a patient receive tPA for an ischemic stroke?
< 3 hours after the onset of symptoms
Cerebral Perfusion Pressure (CPP)
< 50mmHg = vessels are maximally dilated 50-150 = vessel diameter adjusts to keep CBF constant >150 = vessels are maximally constricted
Aortic stensosis is considered severe when aortic valve area is less than
<0.8cm^2
At what level of CBF is there membrane failure and cell death?
<15mL/100g/min
A vital capacity of ______% predicted correlates with requirement for postop ventilation for scoliosis patients
<40% predicted *Assess respiratory reserve with exercise tolerance, ABG, and VC
What GCS is consistent with TBI?
<8
Cerebral hypertension occurs if ICP is...
>20mmHg
intracranial HTN
>20mmHg increased ICP decreased CPP and therefore decreases O2 delivery to the brain. This causes ischemia -> swelling -> decreased CPP -> more ischemia
What vital capacity correlates with requirement for postop ventilation
>40%
Intercostal block technique
A line from T6 to L5 then 5cm from t6 to 7cm to t12 Aim at the rib and very slowly walk of the inferior border inject 3cc per rib( 1.5cc above and 1.5cc below) of .25 bupi
How does a *hypobaric* solution distribute in the *sitting* patient?
A hypobaric sol'n will settle to the highest point of the spinal canal Keep pt sitting - hypobaric sol'n will rise to brain = NOT GOOD
What is the general outline for all blocks?
A.Indication B.(Relative) contraindications: patient refusal, severely demented or combative, coagulopathy, pre-existing hematoma, pre-existing peripheral neuropathy C. Landmarks/Anatomy (VERY IMPORTANT FOR SUCCESS WITH ULTRASOUND-GUIDANCE) D. Muscle stimulation (if using nerve stimulator) E. Amount of drug F. Special consideration/Complications
Hormone produced in the supraoptic nucleus of the hypothalamus
ADH - stimulated by increase in plasma osmolarity(dehydration) the nuclei shrink and stimulates ADH release from posterior pituitary gland
Hormones released by posterior pituitary (2)
ADH and oxytocin
Risks with Marfan's
AI, aortic dissection AAA Cardiac tamponade (if aortic dissection) Mitral prolapse Spontaneous pneumothorax (careful with PIP)
Absence seizure
AKA petit mal Temporary loss of awareness More common in children
Neuraxial recommendations w/ Glycoprotein IIb/IIIa antagonists
Abciximab: b/f block placement hold 1-2 days Tirofiban: b/f block placement hold 8h Eptifibatide: b/f block placement hold 8h
Cranial Nerve VI -Nerve name -Function -Bedside test
Abducens Motor Eye Movement out to sides
Benefits of ultrasound
Ability to see nearby vascular structures Ability to see nerves Ability to visualize the needle approaching the nerve. Ability to see local anesthetic spread. Possibility of reducing complications. Less painful to use Ultrasound instead of nerve stimulator.
How do intracranial tumors, head trauma and volatile anesthetics affect autoregulation?
Abolish/impair autoregulation -CPP dependent on blood pressure
How long does Guillain-Barre persist?
About 2 weeks, with a full recovery in about 4 weeks
Inside the femoral triangle, the femoral n. runs __________________ to the iliopsoas muscle
ANTERIOR
Elderly characteristic associated with greatest risk of 30day mortality? (unplanned ICU admission, emergent surgery, asa 4, acute renal impairment)
ASA 4 status = 12.4% 30day mortality
Treatment for Hyper or Hypokalemic periodic paralysis
Acetazolamide creates non-gap acidosis that counters hypokalemia facilitates renal potassium excretion that counters hyperkalemia
Treatment of familial periodic paralysis for both types:
Acetazolamide (diuretic)- creates non-anion gap acidosis, protecting against hypokalemia, and facilitates renal potassium excretion, guarding against hyperkalemia
Nausea and vomiting from opiates
Activation of opiate receptors in the area postrema of the Medulla and vestibular apparatus
What (3) reduces serum potassium
Albuterol - (B2 agonist) shifts K into cell Insulin - Shift K into liver and skeletal muscle Bowel prep - increases K loss in the feces
Where is the choroid plexus located?
All cerebral ventricles
Fibromyalgia is most closely associated with (neuralgia, dysethesia, allodynia, algesia)
Allodynia - a non-noxious stumulus that produces pain
myasthenia gravis treatment
Anitcholinesterase = oral pyridostigmine is first line tx OD can cause cholinergic crisis and muscle weakness Immunosuppression = steroids, cyclosporine, azothioprine, mycophenolate Surgery = Thymectomy - median sternotomy or transcervical approach Plasmaphoresis = temporary relief during myasthenic crisis or b/f thymectomy
What makes up the anterior and posterior borders of the intravertebral foramina?
Anterior borders: vertebral body and intravertebral discs Posterior borders: fcaet joints
The *femoral n.* provides MOTOR innervation to_______________.
Anterior branch - sartorius Posterior branch - quads
L4 dermatome
Anterior knee
L4 sensory innervation
Anterior knee
Which vertebra does the *lumbar plexus* arise from?
Anterior rami of L1 - L4 (+/- T12)
Which vertebra does the *lumbar plexus* arise from?
Anterior rami of L1 - L4 (occasionally T12)
Where is the *superficial peroneal n.* blocked?
Anterior to the lateral malleolus
Where is the *saphenous n.* blocked?
Anterior to the medial malleolus
What causes SLE symptoms
Antibody induced vasculitis and tissue destruction
Posterior cerebral circulation
Aorta -> Subclavian artery -> vertebral artery -> Basilar artery -> Posterior fossa structures and cervical spinal cord
Anterior spinal artery
Aorta -> subclavian a -> vertebral a -> anterior spinal a Aorta -> segmental a -> posterior radicular a -> anterior spinal a Perfuses the anterior 2/3 of the spinal cord
Posterior spinal arteries
Aorta -> subclavian a -> vertebral a -> posterior spinal a Aorta -> segmental a -> posterior radicular a -> posterior spinal a Perfuses the posterior 1/3 of the spinal cord
Cause of anterior spinal artery syndrome
Aortic cross-clamp above the artery of Adamkiewicz can cause ischemia to the lower portion of the anterior spinal cord
Which valvular disorder is most common in the patient with hx of ankylosing spondylitis?
Aortic insufficiency ankylosing spondylitis is a progressive inflammatory disease
Common cardiac conditions caused by Marfans
Aortic insufficiency & AAA (dilated aortic root), mitral valve prolapse, mitral regurg, aortic dissection, spontaneous pneumothorax is common complication
Side effects of carbamazepine
Aplastic anemia, thrombocytopenia, liver dysfunction, leukopenia, ADH-like effect (hyponatremia)
How does neuraxial anesthesia cause apnea? -What does NOT cause apnea
Apnea is the result of cerebral hypoperfusion -NOT phrenic nerve paralysis or high conc. of LA in CSF -Loss of proprioception input from the chest may cause the patient to complain of dyspnea
Where is cerebrospinal fluid reabsorbed?
Arachnoid villi of the superior sagittal sinus. CSF produced by choroid plexus in all 4 cerebral ventricles at a rate of ~30ml/hr
Cerebellum
Archeocerebellum: Equilibrium Paleocerebellum: regulates muscle tone Neurocerebellum: coordinates voluntary muscle movement
Dermatome
Area of skin innervated by a dorsal nerve root
watershed areas
Areas of the spinal cord that have a single blood supply - particularly susceptible to ischemia
Infraclavicular Block Landmark Image Position of arm
Arm adducted, flexed at elbow with hand resting on abdomen
Supraclavicular indications and Landmarks
Arm, elbow, forearm, wrist, and hand (not shoulder) Landmarks: Subclavian artery (best), clavicle
Where does the *sciatic n.* divide into the *tibial n.* and *common peroneal n.*?
As it passes btwn the major trochanter and the tuberosity of the ischium in the lower 3rd of the thigh
What are the renal and hepatic effects of neuraxial anesthesia?
As long as SBP is maintained, no renal or hepatic blood flow effects
Describe the "triangle" that is formed in the posterior knee for a *popliteal block*
Base = popliteal crease @ knee Apex = convergence of biceps femoris + semitendinosus muscles
Anterior longitudinal ligament
Attached to Anterior surface of the vertebral bodies Extends entire length of spine Attaches to the annulus fibrosis Of intravertebral disc
Tracts in the midbrain
Auditory and visual
How do you prevent central retinal artery occlusion?
Avoid horseshoe headrest- slightest degree of head rotation can compress eye on same side
Anesthetic considerations for familial periodic paralysis (either type) -What 2 things should you avoid?
Avoid hypothermia (even when on CPB) Monitor serum potassium Nondepolarizers are fine in both
Anesthesia considerations with Alzheimer's
Avoid preop sedation, probably not a good candidate for MAC or regional, cholinesterase inhibitors increase DOA of succinylcholine Use short acting drugs to get them back to baseline asap Use glycopyrrolate if an anticholinergic is required- does not cross BBB
Hypobaric solutions (Lighter)
Bupivicaine 0.3% in water Lidocaine 0.5% in water Tetracaine 0.2% in water
Factors that do not significantly affect spread in spinal anesthesia
Barbotage Increased intra-abdominal pressure Speed of injection Orientation of bevel Addition of vasoconstrictor Weight Gender
Epidural veins
Baston's plexus Drain Venus blood from the spinal cord Valveless, Pass through the anterior and lateral regions of epidural space
Anterior spinal artery syndrome is also known as...
Beck's syndrome
Anterior spinal artery syndrome
Becks syndrome Caused by aortic cross-clamp above the artery Adamkiewicz -Flaccid paralysis of the lower extremities -Bowel and bladder dysfunction -Loss of temp and pain sensation -Preserved touch and proprioception
Treatment for post dural puncture headache
Bed rest Hydration nsaids Caffeine Epidural blood patch sphenopalatine ganglion block
Where do upper motor neurons begin and end?
Begin in the cerebral cortex and end in the ventral horn of the spinal cord -Cell bodies originate in cerebral cortex
Where do lower motor neurons begin and end?
Begin in the ventral horn and end at the neuromuscular junction of a muscle -Cell bodies originate in the ventral horn -Lower motor neurons are peripheral motor neurons that link the spinal cord to a muscle
Lower motor neuron
Begins the ventral horn and ends at the NMJ Link the spinal cord to muscles
What muscular diseases are NOT associated w/ MH
Beker muscular dystrophy Neuroleptic malignant syndrome myotonia congenita myotonic dystrophy
When does PaO2 affect CBF?
Below 50-60mmHg will cause cerebral vasodilation and increases CBF (Max vasodilation occurs with PaCO2 80-100 and with CPP <50) -Above 60mmHg it does not affect CBF
(2) descriptions of asynchronous pacing?
Best used for patients with no intrinsic rhythm. Underlying ventricular activity is a risk for R on T phenomenon
Caudal block
Block sacral, lumbar, lower thoracic dermatomes Useful up to a T10 Sensory block
Isobaric solution (Same)
Bupivicaine 0.5% in saline Bupivicaine 0.75% in saline Lidocaine 2% in saline Tetracaine 0.5% in saline
Hyperbaric solutions (Heavier)
Bupivicaine 0.75% in 8.25% dextrose Lidocaine 5% in 7.5% dextrose Tetracaine 0.5% in 5% dextrose Procaine 10% in water
Carbamazepine MOA, metabolism
Blocks voltage gated Na+ channels Membrane stabilizer Hepatic metabolism Hepatic enzyme induction -> resistant to nondepolarizers Also useful for trigeminal neuralgia
Phenytoin MOA, metabolism
Blocks voltage gated Na+ channels Membrane stabilizer Hepatic metabolism Hepatic enzyme induction -> resistant to nondepolarizers Zero order kinetics
Valproic Acid (Depakote) MOA, metabolism
Blocks voltage gated Na+ channels Membrane stabilizer Hepatic metabolism Hepatic enzyme inhibition -> slows phenytoin metabolism
MOA of phenytoin
Blocks voltage-gated sodium channels -membrane stabilizer
Carbamazepine MOA
Blocks voltage-gated sodium channels, membrane stabilizer
MOA of valproic acid
Blocks voltage-gated sodium channels, membrane stabilizer
Causes of increased volume for blood, brain, CSF
Blood: ↑CBF, bleeding Brain: Cerebral swelling, tumor CSF: ↑production by choroid plexus, reduced CSF removal by arachnoid villi, obstruction to reabsorption (infx, bleed, tumor), passage of fluid across the BBB
Sacral cornua
Bony nodules flank sacral hiatus Incomplete development of the faucets
Does ALS affect upper or lower motor neurons?
Both
Cauda Equina s/s
Bowel and bladder dysfxn, sensory dysfxn, weakness +/- paralysis
Muscarinic-2 stimulation causes
Bradycardia M2 receptor slows cardiac conduction
Where do cranial nerves arise from?
Brain and brainstem -12 cranial nerves
What is the cauda equina?
Bundle of nerves extending from conus medullaris to dural sac
Cauda equina
Bundle of spinal nerves extending from conus meddularis to the dural sac
What solutions do you never use with a bier block?
Bupivacaine- difficult resuscitation Epinephrine- ischemia risk Any solution with preservative- risk thrombophlebitis
Deep brain stimulation procedure
Burr hole, insertion of electrodes into the subthalamic nucleus, globus pallidus, and ventralis intermedius- done under sterotactic guidence
3 diseases associated with an increased incidence of malignant hyperthermia
Central core disease Minicore disease King-Denborough syndrome
Subaxial subluxation most commonly occurs at...
C5-C6 *Neck motion can cause SCI *Thoracolumbar spine is generally not affected by RA
Where is the grey matter enlarged in the spinal cord?
C5-C7 - houses cell bodies for neurons that supply the upper extremities L3-S2 - houses cell bodies for neurons that supply the lower extremities
Which nerve roots give rise to each cord?
C5-C7 = LATERAL CORD - ant. div of superior trunk - ant. div of middle trunk C8-T1 = MEDIAL CORD - ant. div of inferior trunk C5-T1 = POST. CORD - post. div of sup. trunk - post. div of middle trunk - post. div of inferior trunk
Which roots give rise to each terminal branch?
C5-C7 = Musculocutaneous C5-C6 = Axillary C5-T1 = Median C5-T1 = Radial C8-T1 = Ulnar
Dermatomes associated with neuraxial anesthetic? C6 - C7 - C8 - T4 - T6 - T10 - T12 - L4 - Face -
C6 - 1st digit (thumb) C7 - 2nd + 3rd digits C8 - 4th + 5th digits T4 - nipple line T6 - xiphoid process T10 - umbilicus T12 - pubic symphysis L4 - anterior knee -Face isn't innervated by a spinal nerve, sensory input is conducted by the trigeminal nerve (CN V)
What vertebral level correlates with the stellate ganglion (cervicothoracic)?
C7
Where is the middle trunk located?
C7
Most common site of a spinal cord injury
C7 Whiplash?
Where is the inferior trunk located?
C8-T1
formula for cerebral blood flow
CBF = Cerebral Perfusion Pressure / Cerebral Vascular Resistance
Critical thresholds for CBF
CBF ~20mL/100g/tissue/min = ischemia CBF ~15mL/100g/tissue/min = complete cortical suppression CBF <15mL/100g/tissue/min = membrane failure & cell death
How does hyperthermia affect the brain?
CMRO2 an cerebral O2 consumption- controlled hypothermia reduces CMRO2
CMRO2 decreases ___% for every 1°C decrease in temperature
CMRO2 decreases 7% for every 1°C decrease in temperature
What nerves control eye movement
CN 3, 4, 6
Which nerves carry pSNS output
CN 3, 7, 9, 10 Oculomotor Facial Glossopharyngeal Vagus Vagus is responsible for 75% of pSNS output
Which cranial nerve is implicated in Bell's Palsy
CN VII: facial ipsilateral facial paralysis
Which cranial nerve is part of the CNS rather than the PNS
CNII: optic meaning it is the only cranial nerve surrounded by dura
What nerve innervates the face (sensory)
CNV: trigeminal
Where does parasympathetic innervation of the gut come from?
CNX - vagus sympathetic innervation comes from sympathetic chain T5-L2
Which laser is most likely to cause corneal injury (Nd:YAG, Argon, CO2, ruby)
CO2 CO2 is long wavelength with absorb more water and do not penetrate deep into tissue, will cause damage to cornea and sclera
Anesthetic mgmt of TBI
CPP > 70mmHg No steroids Avoid prolonged hyperventilation (can worsen cerebral ischemia - only use acutely) Hypertonic fluids Avoid hypotonic solutions & glucose containing solutions (use only for hypoglycemia) Avoid albumin (poorer outcomes) No N2O
What happens if BP is too low?
CPP decreased- autoregulation is often impaired following SAH
Autoregulation range
CPP: 50-150mmHg or MAP: 60-160mmHg CPP = MAP - ICP or CVP (whichever is higher)
CSF reabsorption is dependent on the pressure gradient between ___ and ___
CSF and venous circulation
Blood from SAH can block_____, which causes:
CSF flow which causes hydrocephalus and increased ICP
Major chemical differences between CSF and plasma
CSF has lower potassium, lower PaCO2, lower pH, lower glucose and extremely lower protein content (almost none)
Which anticonvulsant is also useful for trigeminal neuralgia?
Carbamazepine
Embolism also is a big risk for central retinal artery occlusion, which surgery poses the biggest risk?
Cardiac surgery with CPB
A *median n.* block should be avoided in a patient with _____________________.
Carpel Tunnel Syndrome
Effect of phenytoin on NDMBs
Causes hepatic enzyme induction and therefore causes resistance to nondepolarizers (higher dose of NMB)
Effect of carbamazepine on NDMRs
Causes hepatic enzyme induction, and therefore resistance to nondepolarizers
Transient neurologic symptoms
Causes: patient positioning, stretching of sciatic nerve, myofascial strain, muscle spasm Increased risk: Lidocaine, lithotomy position, ambulatory surgery, knee arthroscopy S&S:Severe back and butt pain radiates to both legs Develops within 6 to 36 hours Persist for 1-7 days Treatment: NSAIDs, opioid analgesics, trigger point injections
Which optic arteries are at highest risk of ischemia?
Central retinal and posterior ciliary arteries
Intracranial HTN reduces O2 delivery to the brain. What does this cause (cycle)?
Cerebral ischemia -> cerebral swelling -> decreased CPP -> more ischemia
5 determinants of CBF
Cerebral metabolic rate for oxygen (CMRO2) Cerebral perfusion pressure Venous pressure PaCO2 PaO2
Diseases of the upper motor neuron
Cerebral palsy ALS
Examples of upper motor neuron disease
Cerebral palsy and amyotrophic lateral sclerosis
Causes of increased brain volume
Cerebral swelling Tumor
Cervical & thoracic spinous process directionality vs lumbar spinous process directionality
Cervical & thoracic: angled in a caudal direction Lumbar: posterior direction
What are the 5 divisions of the spinal column? How many vertebrae are present in each?
Cervical (C1-C7) Thoracic (T1 - T12) Lumbar (L1 - L5) Sacral (S1 - S5 - fused) Coccygeal (4 fused = coccyx) *33 vertebrae total
Complete spinal cord injury damages upper/lower neurons -Initial symptoms -After acute phase, what happens?
Complete spinal cord injury damages upper neurons -Initial symptoms: flaccid paralysis, loss of sensation, loss of bowel and bladder function, possibly neurogenic shock -After acute phase: spinal reflexes return and may lead to spasticity
Spinal Anesthesia Spread -Controllable factors (4) -Non-Controllable Factors (2)
Controllable Factors: - baricity of LA - position during + after block placement - dose - site of injection Non-controllable Factors: - volume of CSF - density of CSF
Factors that significantly affect the spread in spinal anesthesiaP
Controllable Factors: -baricity of local anesthesia -patient position -Dose -site of injection Uncontrollable Factors: -Volume of CSF -Density of CSF
Reticular activating system function
Controls consciousness, arousal, and sleep
plica mediana dorsalis
Controversial Band of connective tissue Courses between ligamentum flavum and Dura matter
Neocerebellum
Coordinates voluntary muscle movement -Structure of cerebellum "new movements"
What are the landmarks for infraclavicular block?
Coracoid process, clavicle
Infraclavicular block is what level block?
Cord level
Infraclavicular block level
Cords (posterior, medial, lateral)
What do cords give way to?
Cords give off Branches of nerve terminals
Where do cords turn into terminal branches?
Cords separate into terminal branches in the *axilla*
Most common eye complication in the perioperative period
Corneal abrasion
What are the two classifications of spinal needles?
Cutting tip and pencil point
Intermediate signs of MH
Cyanosis Patient warm to the touch Irregular heart rhythm
Intermediate signs of MH
Cyanosis, patient warm to touch, irregular heart rhythm
Which nerve fibers and tracts are perfused by the anterior blood supply?
Corticospinal tract (flaccid paralysis of lower extremities), Autonomic motor fibers(bowel/bladder dysfunction) Spinothalamic tract (lose pain and temp sensation)
Describe the anatomical position of the The *posterior femoral cutaneous n.*
Courses distally w/ sciatic n. before taking a superficial course as it emerges through piriformis muscle
Anesthetic considerations for MS
Cranial nerve involvement causes bulbar muscle dysfxn -> aspiration risk Hyperthermia & stress can cause exacerbations Succ can cause life-threatening hyperkalemia
What are the 3 types of epidural needles? How do they differ from each other?
Crawford = 0 deg Hustead = 15 deg Tuohy = 30 deg Differ in angle of needle tip. Note the angle inc in alphabetical order!
Aortic dissection least likely to cause aortic insufficiency?
Crawford type 1
in DMD the breakdown of the sarcolemma allows for what markers to circulate?
Creatine phosphokinase and myoglobin to enter circulation
What proteins exit the cells due to the lack of dystrophin
Creatinine phosphokinase and myoglobin
Which disease is cause by a prion? (H1N1, Creutzfeldt-jakob, legionaires, middle east sars)
Creutzfeldt-jakob
Airway complications of SLE
Cricoarytenoiditis - hoarseness, stridor, airway obstruction Recurrent laryngeal nerve palsy
Dystrophin
Critical structural component of the cytoskeleton of skeletal and cardiac muscle cells Helps anchor actin and myosin to the cell membrane
Where do second order neurons of the anterolateral system travel?
Cross to contralateral side of the spinal cord then ascend toward the brain via the anterior spinothalamic tract and lateral spinothalamic tract
Where does the second order neuron of the dorsal column travel?
Crosses to the contralateral side in the medulla, then ascends toward the thalamus via the medial lemniscus
Second order neuron (Anterolateral)
Crosses to the contralateral side of the spinal cord Ascends toward the brain via 2 pathways: anterior spinothalamic & lateral spinothalamic Cell body in the dorsal horn Synapse in the Reticular Activating System or the thalamus
Ventral spinothalamic tract is responsible for what sensation?
Crude touch and pressure
The obturator n. arises from ___________.
L2 - L4
What may be useful for sedation and tremor reduction in a patient with Parkinson's?
Diphenhydramine (Benadryl)
Acceptable response to nerve stimulator (interscalene)
Deltoid (shoulder abduction) Pectoralis major (arm internal rotation) Biceps (forearm flexion) Triceps (forearm extension) Any twitch of the hand or arm
Which part of the neuron receives and processes signals?
Dendrites
Affect of adding opioids to neuraxial block
Denser block -they also diffuse into the systemic circulation and bind to opioid receptors in the body
Define baricity
Density of LA relative to the CSF
What is a dermatome? Myotome?
Dermatome - area of skin innervated by a dorsal nerve root from the spinal cord. Not necessarily the area of skin that is in the same planes a the spinal nerve Myotome - depicts the muscles innervated by the ventral nerve root from the spinal cord
The absence of dystrophin ______ sarcolemma during muscle contraction which _________ membrane permeability
Destabilizes the sarcolemma Increases membrane permeability
What should be done first for a patient experiencing a CVA?
Determine the type via non-contrast CT
Key findings in Alzheimer's
Development of diffuse beta amyloid rich plaques and neurofibrillary tangles in the brain Causes dysfunction synaptic transmission and apoptosis
Most potent glucocorticoid properties (increase in glucose): (aldosterone, prednisone, dexamethasone, methylprednisone)
Dexamethasone
Best antiemetic for patient with prolonged QT interval (droperidol and transdermal scop, ondansetron and droperidol, ondansetron and dexamethasone, scop and dexamethasone)
Dexamethasone and transdermal scopolamine
Dextrose vs water affect on baricity
Dextrose = Increases it (hyperbaric) -> more likely to sink Water = Decreases it (hypobaric) -> more likely to rise saline is generally isobaric
Other than as an anticonvulsant, what is gabapentin useful for?
Diabetic neuropathy, postherapetic neuralgia, reflex sympathetic dystrophy
What causes non-gap metabolic acidosis? (3)
Diarrhea Renal Tubular Acidosis Excessive chloride administration non-gap acidosis is due to loss of HCO3- (or increased Cl-)
Classic problem in Marfan's
Dilated aortic root - aortic insufficiency and aortic dissection
The *obturator n.* provides SENSORY innervation to ___________________.
Distal inner thigh + part of hip
Methods to reduce cerebral edema
Diuretics Hypertonic fluid Corticosteroids (NOT for TBI)
What do divisions combine into?
Divisions combine to form Cords: Lateral, Medial and Posterior
Where do divisions turn into cords?
Divisions converge into cords when BP goes *under the pectoralis minor* muscle
Gabapentin s/e
Dizziness Somnolence Can produce seizure in patients w/ seizure history, need a taper
Duchenne muscular dystrophy
Does not code for dystrophin, which destabilizes the sarcolemma during muscle contraction and increases membrane permeability Extracellular Ca enters the cell, intracellular K exits the cell - can result in hyperkalemic cardiac arrest Myoglobin is free to exit the cell, causing renal failure
Difference of gabapentin compared to other anticonvulsants
Does not induce hepatic enzymes
Parkinson's pathophysiology
Dopaminergic cells in the basal ganglia are destroyed TOO MUCH ACETYLCHOLINE + TOO LITTLE DOPAMINE = overstimulation of basal ganglia Increased Ach in the basal ganglia stimulates GABA activity in the thalamus (suppresses the thalamus) Overactivity of the extrapyramidal system
What is different about the basal ganglia in a patient with Parkinson's?
Dopaminergic neurons are destroyed, favoring a relative increase in cholinergic activity Increased ACh in the basal ganglia increases GABA activity in the thalamus, suppressing the thalamus which suppresses the cortical motor system and motor areas of the brainstem--> results in over activity of extrapyramidal system
Sensory tracts
Doral column: Cuneatus & Gracilis = Fine touch & proprioception Tract of Lissauer: Part of spinothalamic tract Lateral spinothalamic tract: Pain & Temp Ventral spinothalamic tract: Crude touch & pressure
Which column allows for two-point discrimination?
Dorsal column/medial lemniscal system
Where do sensory neurons from periphery enter the spinal cord?
Dorsal nerve root
First order neurons enter the spinal cord via the______. It relays the sensory info from the _______ to the_____
Dorsal root ganglion From dorsal root column to the Medulla
Where are pseudounipolar neurons found?
Dorsal root ganglion and cranial ganglion
Acute treatment of hydrocephalus
Drain placed in lateral ventricles or intrathecal space Draining CSF is most useful when there is an obstruction to CSF, like hydrocephalus.
Forms of skeletal muscle myopathy
Duchenne (most common) Becker, Emery-Dreifuss, facioscapulohumeral, and limb-girdle
Most common form of skeletal muscle myopathy
Duchenne muscular dystrophy -x-linked, recessive disease results from absence of dystrophin protein
Terminal end of subarachnoid space
Dural sack S2 in adult S3 in infants
Phenytoin s/e
Dysrhythmias w/ Hypotension (if rate > 50mg/min) Gingival hyperplasia Aplastic anemia Cerebellar vestibular dysfxn - nystagmus, ataxia Stevens-Johnson syndrome Birth defects
Side effects of phenytoin
Dysrhythmias, hypotension Gingival hyperplasia Aplastic anemia Cerebellar vestibular dysfunction (nystagmus, ataxia) Stevens-Johnson syndrome Birth defects
Amygdala functions
Emotion, appetite, responds to pain and stressors -Structure of the cerebral hemisphere
Neuraxial recommendations w/ low molecular weight heparin
Enoxaparin, Dalteparin, Tinzaparin: b/f block placement (prophylactic dose) hold 12h, (therapeutic dose) hold 24h b/f removing catheter hold 12 h After removing catheter hold 2h
Where do first order neurons of the anterolateral column travel?
Enter through the dorsal root ganglion, ascend 1-3 levels on the ipsilateral side via the Lissauer tract
Which cells form the choroid plexus?
Ependymal cells
What is the primary risk of neuraxial anesthesia in the anticoagulated patient?
Epidural hematoma - can cause paralysis! Risk is similar during block placement and catheter removal
Safety of epidural/spinal with MS
Epidural is safe Spinal may exacerbate symptoms
Which neuraxial opioid can reactivate HSV labialis?
Epidural morphine d/t cephalad spread to trigeminal nucleus presents 2-5 days post-epidural admin *cold sores
Do not use _______ containing solution bc...
Epinephrine; bc risk of ischemic injury
Laws illustrated in the Fick equation (2)
Fick law of diffusion describes transfer rate of gas through a tissue medium Henry - amount of gas that dissolves in solution is directly proportional to the partial pressure of that gas over the solution Graham- rate of gas diffusion is inversely proportional to the square root of its molecular weight
Basal ganglia functions
Fine control of movement -Structure of the cerebral hemisphere "fine control when adding basal to food"
Dorsal column is responsible for for what sensation?
Fine touch and proprioception specific areas are named Cuneatus &Gracillis
Acceptable response to twitch monitor (supraclavicular)
Finger twitch
C6 sensory innervation
First digit thumb
Which types of nerve fibers are blocked first? (Spinal Anesthesia)
First: autonomic fibers Second: sensory fibers Third: Motor neurons
S/Sx of Guillain-Barre
Flaccid paralysis begins in distal extremities and ascends bilaterally (Proximal extremities-->trunk-->face) Intercostal muscle weakness, facial and pharyngeal weakness Paresthesias, numbness, pain
How do you block the *ulnar n.* at the elbow? Volume in ml? Where does it derive from?
Flex elbow 90 degrees Inject btwn *olecranon* + *medial epicondyle* of humerus Volume = 3-5mL -medial cord brachial plexus
Ulnar nerve movement
Flexion of wrist Adduction of all fingers Flexion and opposition of medial two fingers toward thumb [dont worry about thumb movement here]
Hypobaric solution In supine position
Float Towards lower lumbar region
Poiseuille's Law equation= If you triple the radius it will cause flow to increase by a factor of=
Flow = (pi*r^4*change in P) / (8nl) Flow = (3.14 x Radius^4 x pressure difference / 8 x viscosity x length by a factor of 81
Facet joint
Form by the Superior articular process of one vertebrae and inferior Articular process of the vertebrae directly above it Guides And restricted movement of the vertebral column Injury:Can't compress spinal nerveCausing pain and muscle spasm
What are the anatomic boarders of the facet joint? -Facet joint function -Injury to facet join can cause...
Formed by the sup. articular processes of one vertebra and the inf. articular processes of the vertebra directly above -Facet joint guides and restricts movement of the vertebral column -Injury to the facet joint can compress the spinal nerve that exists the respective intervertebral foramina, causing pain and muscle spasm along the associated dermatome
How does blood cause vasospasms in the cerebrum?
Free hgb in contact with outer surface of the cerebral arteries increases risk of vasospasm
Peripheral receptors in the anterolateral system
Free nerve endings Nociceptive receptors
What should be avoided during DBS?
GABA agonists, such as propofol and benzos, because they can interfere with electrophysiologic brain monitoring
GI considerations for DMD
GI hypomotility and impaired airway reflexes= increased risk of pulm aspiration
Neuraxial recommendations w/ Herbal therapies
Garlic, Ginko, Ginseng Proceed if pt not on other blood thinners
GI complications from RA
Gastic ulcerations d/t steroids and NSAIDs
Best options of anesthetic management to prevent autonomic hyperreflexia
General or spinal -Pt does not have sensation below the level of SCI, stimulation to the affected areas can elicit autonomic hyperreflexia. Prevention is key!
Anesthetic mgmt of AH
General or spinal anesthesia is preferred (better than epidural) Epidural can be used for laboring mother but it does not inhibit the sacral root to the same degree Treat HTN w/: removal of stimulus, deepen anesthetic, rapid acting vasodilator (nipride) Treat bradycardia w/ atropine or glyco Do not give chronotropic agents Lidocaine jelly on catheters does not help Succ is contraindicated May present in postoperative period after anesthesia wears off
Trans arterial approach to axillary block
Go THROUGH the artery Inject 40 cc of local - posterior or posterior and anterior to the artery. Apply distal pressure for cephalad spread
Where do you go for the Infraclavicular Block?
Go under the clavicle, lateral to subclavian
Risk factors for Parkinson's
Greatest risk is old age Exposure of manganese (welders), herbicides, pesticides, and possibly genetics
Rounded Bevel tip needle
Greene
The cell bodies form what kind of matter?
Grey matter
Most common cause of acute, generalized paralysis
Guillain-Barre syndrome
GI effects of neuraxial anesthesia -Gut receives parasympathetic innervation from ___, sympathetic innervation from ___ -Inhibition of sympathetic chain causes what? Why?
Gut receives parasympathetic innervation from vagus nerve (CN X), sympathetic innervation from T5-L2 -Inhibition of sympathetic chain between T5-L2 allows unopposed parasympathetic output to the gut and causes sphincters to relax and increases peristalsis "If you had a Take 5 (T5) bar for lunch and are late TWO (L2) dinner you will be running(sympathetic) because of hunger"
s/s intracranial HTN
H/A N/V Papilledema Focal neurologic deficit ↓LOC seizure coma
Methods to increase venous outflow
Head positioning = avoid flexion and extension, avoid head down, head up >30mmHg increases outflow Reduce intrathoracic pressure (PEEP, bucking, coughing, straining)
What are the clinical implications of phrenic nerve paralysis?
Healthy patients: NBD COPD patients: - severe dyspnea - hypercapnia - hypoxemia
A alpha peripheral nerve fibers
Heavy myelinated Function: skeletal muscle, Motor proprioception diameter: 12 to 20 µm Velocity: Very high Block of onset: fourth
A beta peripheral nerve fibers
Heavy myelination Function: touch, pressure In diameter: 5 to 12Micrometers Velocity:Moderately high Block onset: fourth
A-beta Nerve Fiber -Myelination -Function -Diameter -Conduction velocity -Block onset
Heavy myelination Function: Touch, Pressure 5 - 12 ++++ 4th Beta men are always trying to touch you and pressure you into stuff.
Complications with axillary block:
Hematoma if using transarterial approach LA toxicity if injected into artery
Neurogenic shock
Hemodynamic derangement associated with spinal cord injury instability is greatest with injuries to the cervical or upper thoracic cord. the higher the injury the greater the degree of instability Can be confused w/ hypovolemic shock
If endovascular coil is placed what will the patient require?
Heparinization
Side effects of valproic acid
Hepatotoxicity Thrombocytopenia - increased surgical bleeding, especially in kids
Epidural morphine it may react to with:
Herpes simplex Labialis cephalad spread of morphine on trigeminal nucleus 2 to 5 days after epidural morphine admin
Subdural space
High spinal with epidural dose Failed spinal with spinal dose
Effect of high venous pressure on the brain
High venous pressure decreases cerebral venous drainage, increasing cerebral volume (ICP)
The level of sensory blockade is _______ than motor block (Spinal Anesthesia)
Higher 2 dermatomes higher than motor
*Hydrophilic* Opioids: Nausea + vomiting
Higher incidence
*Hydrophilic* Opioids: Pruritus
Higher incidence -Histamine release with these drugs
The *obturator n.* is prone to injury during extensive _________________ surgery.
Hip
The *obturator n.* provides MOTOR innervation to ___________________.
Hip ADDuctors
Obturator n. MOTOR innervation: Sensory innervation:
Hip ADDuctors Distal inner thigh + part of hip
Deep brain stimulation for Parkinson's
Hold levodopa to allow for better mapping Burr hole awake, lightly sedated (do not use GABA agonists - precedex, opioids) precordial doppler for air embolism d/t sitting position SBP < 140
Cauda equina
Horses tail bundle of spinal nerves extending from conus medullaris to dural sac
How does lipophilicity affect rostral spread in the subarachnoid space?
Hydrophilic drugs tend to remain in the subarachnoid space and travel toward the brain (rostral spread) Lipophilic drugs tend to diffuse out of the subarachnoid space and enter the systemic circulation
Which are more likely to remain in the CSF? sufentanil, hydromorphone, meperidine, fentanyl
Hydrophillic opioid remains in the CSF and achieves a higher level of block. Meperidine, hydromorphone,
Hyperbaric is in what solution? (except what?) Isobaric is in what solution? Hypobaric is in what solution?
Hyperbaric- dextrose (except 10% procaine in water) Isobaric- saline Hypobaric- water
Conditions that increase specific gravity
Hyperglycemia uremia High protein content Advanced aged Colder temperature
Conditions that increase specific gravity
Hyperglycemia Uremia High protein content Advanced age Colder temperature
What side effect from corticosteroids is associated with worse outcomes?
Hyperglycemia -Hyperglycemia during cerebral ischemia is associated with worse outcomes
Blood sugar during stroke
Hyperglycemia = glucose is converted to lactic acid during ischemic stroke which causes acidosis which destroys brain tissue
Conditions to avoid post CVA
Hyperglycemia and hyperthermia
Stroke RF
Hypertension (most important) Smoking DM HLD Excessive alcohol intake elevated homocysteine levels
Classic presentation of autonomic hyperreflexia
Hypertension and bradycardia
Cushing's triad -What is it a sign of? -How are these symptoms produced?
Hypertension, bradycardia, irregular respirations -Sign of intracranial HTN -Increased ICP reduces CPP. To preserve cerebral perfusion the BP is increased. Increased BP activates baroreceptor reflex and causes bradycardia. The medulla compensates for bradycardia and causes irregular respirations
Late signs of MH
Hyperthermia Cola-colored urine Coagulopathy Muscle rigidity
CMRO2 is increased by...(4)
Hyperthermia Seizures Ketamine Nitrous oxide
Effect of fluids: Hypertonic Hypotonic Glucose containing Albumin
Hypertonic: restores intravascular volume and decreases brain water Hypotonic: AVOID- increases cerebral edema Glucose containing: worsen neuro outcomes in setting of cerebral ischemia (only reserve for hypoglycemic) Albumin: linked to poor outcome
Methods to ↓ CBF
Hyperventilation (↓PaCO2 ~30-35mmHg) Avoid hypoxemia (keep PaO2 > 60mmHg Avoid vasodilators (NTG, nipride) Drugs that reduce CMRO2 are ok (thiopental, propofol) Avoid extreme HTN - BP above the autoregulation curve contributes to edema
What should you specifically avoid in a patient with a TBI? (2)
Hyperventilation - can worsen cerebral ischemia Steroids- worsen neurologic outcome- increased glucose--> glucose--> lactic acid
Cardiovascular complications associated with acute pancreatitis include all of the following except: (myocardial depression, pericardial effusion, thrombophlebitis, hypervolemia)
Hypervolemia
*What is the triple H therapy for vasospasm?
Hypervolemia, hypertension, hemodilution (Hct 27-32) liberal hydration supports BP, hemodilution decreases blood viscosity *note little evidence*
What are the landmarks to look for when using the ultrasound?
Hypoechoic pulsating subclavian artery (superior to first rib)
Cranial Nerve XII -Nerve name -Function -Bedside test
Hypoglossal Motor Tongue movement
If ICP is normal (__-___), MAP must be ___ to ensure a CPP of 50mmHg. -Elevated ICP requires a higher/lower MAP for perfusion
If ICP is normal (5-15), MAP must be 55-65 to ensure a CPP 50mmHg. Elevated ICP requires a higher MAP for perfusion -LARGE patient to patient variability
Which nerve roots give rise to the *lateral femoral cutaneous nerve*?
L2 + L3
Anesthetic implications for hypothyroid patients
Hypotension Aspiration- 2nd to decreased gastric emptying Does NOT affect MAC, but changes in CO affect the FA/FI relationship and speed of anesthetic induction.
What is the primary neurohumoral organ? What does it do?
Hypothalamus Regulates body temp thirst/appetite/wt control sleep cycles BP/HR
CMRO2 is decreased by... (5)
Hypothermia Halogenated anesthetics Propofol Etomidate Barbiturates
Temp control for periodic paralysis
Hypothermia must be avoided at all costs Pt's are kept normothermic even during CPB
Which laminae are sensory?
I - VI
Cranial Nerve Functions
I. (Olfactory) Some: Sensory Function II. (Optic) Say: Sensory Function III. (Oculomotor) Money: Motor Function IV. (Trochlear) Matters: Motor Function V. (Trigeminal) But: Both Sensory and Motor Function VI. (Abducens) My: Motor Function VII. (Facial) Brother: Both Sensory and Motor Function VIII. (Vestibuloclear) Says: Sensory Function IX. (Glossopharyngeal )Big: Both Sensory and Motor Function X. (Vagus) Brains: Both Sensory and Motor Function XI. (Accessory) Matter: Motor Function XII. (Hypoglossal) More: Motor Function
functions of CN III, IV, VI
III: Eye movement (all except cross eyed and lateral) & pupil constriction IV: Eye movement (cross eyed) VI: Eye movement (lateral)
Inside th femoral triangle, the femoral n. runs ________________ to the fascia lata and fascia iliaca
INFERIOR
Inside the femoral triangle, the femoral n. runs ________________ to the fascia lata and fascia iliaca
INFERIOR
Which nerve roots give rise to the *femoral nerve*?
L2 + L3 + L4
How does N2O cause central retinal artery occlusion?
If nitrous gets used following retinal detachment surgery with intraocular bubble placement
Kidney and liver effects of neuraxial analgesia
If systemic blood pressure maintained, hepatic and renal bloodflow unchanged
Pathophysiology of myasthenia gravis
IgG antibodies destroy post-junctional, nicotinic, acetylcholine receptors at the NMJ *Ach is present, but not enough receptors to translate signal to intracellular response so you get skeletal weakness G for ground
What is Eaton-lambert syndrome caused by?
IgG mediated destruction of presynaptic Ca+ channels at the presynaptic terminal "EL"- elevator upper NMJ Myasthenia Gravis -"Ground" lower NMJ
6 nerves that arise from the lumbar plexus "I Instantly Get Lazy On Fridays
Iliohypogastric Ilioinguinal Genitofemoral Lateral femoral cutaneous Obturator Femoral
Name the 6 terminal branches of the *lumbar plexus*
Iliohypogastric - I Ilioinguinial - Invariably Genitofemoral - Get Lateral femoral cut. - Lazy Obturator - On Femoral - Fridays
*Lumbar Plexus* Primary Nerves
Iliohypogastric n. Ilioinguinal n. Genitofemoral n. Lateral femoral cut. n. Obturator n. Femoral n.
What do you do if the aneurysm ruptures during the procedure?
Immediately reverse heparin with 1mg protamine for every 100U of heparin given MAP should be low end normal *Adenosine can be given to temporarily arrest heart so interventional radiologist can control bleeding
Guillain-Barre
Immunologic deterioration of myelin in the peripheral nerves- action potential can't be conducted so motor endplate doesn't receive the incoming signal
Which option can be a source of coagulopathy (VitK supplementation, increased cholecystokinin, sphichterotomy of the sphincter of Oddi, impaired bile production)
Impaired bile production Impaired bile production reduced absorptiono f vitamin K. Vitamin K is important in producing factor 2,7, 9, 10
EKG changes with DMD
Impaired cardiac conduction -> ST & short PR interval Increased R wave amplitude in lead I and deep Q waves in the limb leads
Pathophysiology of neurogenic shock
Impairment ot cardioaccelorator fibers (T1-T4) Decreased SNS tone -> vasodilation -> venous pooling -> decreased CO & BP Impairment of sympathetic pathways from hypothalamus to blood vessels -> inability to vasoconstrict or shiver -> hypothermia
What diameter needle is helpful in an in plane approach?
In Plane approach: A larger diameter needle can be helpful, especially if the nerve is relatively deeper, and a longer needle is required.
Gastrointestinal effects of neuraxial analgesia
Inhibition of sympathetic chain between a T5 to L2 Allows parasympathetic outputTo function unopposed Causes of sphincters to relax and increases peristalsis
How do you block the *median n.* at the forearm? Volume in ml? Where does it derive from?
In the AC fossa, inject *medial to brachial a.* (brachial artery is medial to biceps tendon) Volume = 3-5mL lateral and medial cord of BP
Where do first order neurons of the anterolateral system synapse with second order neurons?
In the dorsal horn laminae I, IV, V, and VI
Where do first order neurons of the dorsal column synapse with the second order neuron?
In the medulla (cuneate (upper limbs) and gracile (below T6-lower limbs nuclei are first order neurons carry the signal)
When is weakness worst with Eaton-Lambert syndrome?
In the morning Gets better throughout the day "eating breakfast is hard in the morning"
Where do second order neurons of the anterolateral system synapse?
In the reticular activating system (pain signals) and the thalamus (tactile signals)
Where do second order neurons of the dorsal column synapse with third order neurons?
In the thalamic relay station - ventrobasal complex
What is the risk of neuraxial technique in a pt w/ inc. ICP?
Inc. risk of brain herniation w/ sudden changes in CSF pressure
Parkinson's treatment
Increase dopamine levels or decrease Ach in basal ganglia levodopa (L-dopa/ Sinemet) & Carbadopa Levodopa is metabolized to DA in the blood and cannnot cross the BBB. Carbadopa is a decarboxylase inhibitor so it inhibits the metabolism of levodopa to DA, allowing levodopa to make it into the brain
Methods to decrease CSF
Increase drainage (Ventric) Acetazolamide and lasix decrease CSF production
Monro-Kellie hypothesis
Increase in volume of one component (brain, blood, CSF) must be compensated by a decrease in volume of another, or pressure inside the cranium will rise
When Levodopa and carbidopa are given together they:
Increase the concentration of dopamine at the basal ganglia
Causes of increased blood volume
Increased cerebral blood flow Bleeding
Side effects of levodopa and carbidopa
Increased inotropy, tachycardia, orthostatic hypotension Dyskinesia, nausea, vomiting
If an RSI is required in a patient with myasthenia gravis, how should you dose succinylcholine?
Increased resistance Increase to 1.5-2mg/kg
Other Anesthetic considerations with Guillain-Barre
Increased risk of aspiration, may need postop ventilation Risk for hemodynamic instability (position changes, anesthetics, PPV, blood loss) Exaggerated response to indirect-acting sympathomimetics d/t upregulation of postjunctional adrenergic receptors *regional anesthesia is controversial *steriods not useful
What happens if the BP is too high post op aneurysm repair?
Increased transmural pressure and risk of rebleed
Why should PaCO2 not be reduced to lower than 30mmHg?
Increases the risk of cerebral ischemia d/t vasoconstriction and left shift in oxyhgb curve which causes reduced O2 offloading
Opioids have an antidiuretic effect by:
Increasing Vasopressin release
SLE exacerbation
Induced by stress or drug exposure PISSED CHIMP P = Pregnancy I = Infection S = Surgery S = Stress E = Enalapril D = D-penicillamine C = Captopril H = Hydralazine I = Isoniazid M = Methyldopa P = Procainamide
Major causes of morbidity and mortality in patients with cervical and upper thoracic SCI
Ineffective alveolar ventilation and inability to clear pulmonary secretions
What procedures work best with an *infraclavicular block*?
Infraclavicular approach is a cord level block Best for procedures BELOW elbow
What is malignant hyperthermia?
Inherited disease of skeletal muscle that involves disordered Ca+ homeostasis
Complications of Axillary Block
Intravascular injection Hematoma Inadequate anesthesia of the musculocutaneous nerve*****
Gold standard of ICP measurement
Intraventricular catheter -ICP can also be measured with a subdural bolt or a catheter placed over the convexity of the cerebral cortex
Which nerve roots give rise to the *obturator nerve*?
L2 + L3 + L4
What can be added to the LA to assist with postoperative analgesia?
Ketorolac (15-30mg) *does not increase the risk of bleeding
The *lateral femoral cutaneous n.* arises from ________________.
L2 - L3
The *femoral n.* arises from __________.
L2 - L4
The *obturator n.* arises from ___________.
L2 - L4
Which organ is most susceptible to cyclosporine toxicity
Kidney cyclosporine is a calcineurin inhibitor. Calcinuerin inhibitors reduce GFR by causing profound vasoconstriction of the afferent arteriole
MH is linked to 3 other co-existing diseases:
King-Denborough syndrome Central core disease Multiminicore disease *possibly hypokalemic periodic paralysis
In 10% of the population, the artery of Adamkiewicz originates between...
L1-L2
INFANT Conus Medullaris
L3
Which spinal level is designated by the intercristal line?
L4 A horizontal line drawn across the superior aspects of the iliac crest designates the intercristal or Tuffiers line.
The *sciatic nerve* arises from _____________.
L4 - S3
Which vertebrae does the *sacral plexus* arise from?
L4 - S4
Which vertebrae does the sacral plexus arise from?
L4 - S4
Tuffier's Line
L4-L5 interspace (correlates with the iliac crest)
Which spinal nerves are most resistant to local anesthetics
L5 & S1 = largest nerves It is also the largest interspace
What does it mean if an LA is *hyperbaric*?
LA has higher density vs. CSF Solutions in dextrose = hyperbaric Hyperbaric solution will SINK
What does it mean if an LA is *hypobaric*?
LA has lower density vs. CSF Water Hypobaric solution will RISE
What does it mean if an LA is *isobaric*?
LA has similar baricity to CSF Solutions in saline = isobaric Isobaric solution will remain where it is injected
biggest concern with any block is?
LAST (local anesthetic systemic toxicity)
The *lateral femoral cutaneous n.* provides SENSORY innervation to:
LATERAL THIGH
All of the following are anesthetic considerations for the patient with a tonsilar bleed except (LMA, requires RSI, volume restricted before induction, hemorrhage most commonly occurs within 24hours of surgery)
LMA LMA is actually contraindicated
*Hydrophilic* Opioids: How long do they stay in CSF?
LONGER period of time vs. lipophilic
This cord gives off a branch of the median nerve and ends as the musculocutaneous
Lateral cord
Lateral corticospinal tract -What does it innervate -Where does it cross over
Lateral corticospinal tract: Fibers that innervate the limbs cross over to the contralateral side in the medulla -From here, they descend the spinal cord via this tract. Synapse in the ventral horn to the limb muscles "Lateral: LiMbs (limbs and medulla)"
Motor tracts
Lateral corticospinal tract: Limb motor Ventral corticospinal tract: Posture motor
What position does the patient need to be in for the psoas block?
Lateral decubitus with side to be blocked in non-dependent position- be able to easily visualize the quadriceps muscle
Caudal technique
Lateral or prone Sims position Landmarks: iliac spines & sacral hiatus 22-25g needle, 20g IV Placing needle above S2-3 increases risk of dural puncture Do not use air for loss of resistance (air embolism)
Flow of CSF
Lateral ventricles Foramen of Monro 3rd ventricle Aqueduct of Sylvius 4th ventricle Foramen of Luschka and Magendie Subarachnoid Space Superior sagittal sinus/arachnoid villi "Love My 3 Silly 4 Lorn Magpies"
How does a *hyperbaric* solution distribute in the *supine* patient?
Lay down after block - hyperbaric sol'n will slide down lumbar lordosis and eventually pool in *sacrum* and *thoracic* kyphosis (T4)
How does a *hypobaric* solution distribute in the *supine* patient?
Lay down after block - sol'n will float toward lumbar region DOES NOT float toward cervical region, b/c that would 1st require LA to sink into thoracic kyphosis
What lead is best for diagnosing dysrhythmias?
Lead II
What medications are typically used for an interscalene block?
Lidocaine 1-1.5%, Bupivacaine .2-.375%, Ropivacaine .2-.5, Mepivicaine 1%
Where does the artery of Adamkiewicz most commonly originate?
Left side between T11-T12 11 letters in adamkiewicz
*Hydrophilic* Opioids: Systemic absorption
Less (this is why it stays in CSF longer)
The three terminal nerves of the hand can be blocked at what 2 places?
Level of the forearm or wrist- useful for surgery on forearm/hand or for rescue block of a nerve that was missed during BP block ** these are good hotspot questions***
Treatment for Parkinson's
Levodopa/carbidopa Selegiline Dopamine agonists Anticholinergics COMT inhibitors (catechol-o-methyltransferase) Amantadine Hormone replacement
B Nerve Fiber -Myelination -Function -Diameter -Conduction velocity -Block onset
Light myelination Function: Preganglionic ANS 3 ++ 1st
B peripheral nerve fibers
Lightly myelinated Function: Preganglionic ANS fibers Diameter: 3 µm Velocity: second slowest Block onset: first
Lateral corticospinal tract is responsible for:
Limb motor
Respiratory depression caused by: Lipophillic opioids: More quickly absorbed by the _______ tissue, which limits amount of _______. In the epidural space, ________ a lipophilic drug in ______cc of preservative free Nacl will _______ spread. Early phase resp depression results from: Late phase?
Lipophillic opioids: More quickly absorbed by the spinal tissue, which limits amount of spread. In the epidural space, diluting a lipophilic drug in 10cc of preservative free Nacl will enhance spread. Early phase: results from systemic absorption Late phase? no late phase
Conditions and decreases specific gravity
Liver disease jaundice Warmer temperature
Conditions that decrease specific gravity
Liver disease Jaundice Warmer temperature
What is the main risk of a Bier block?
Local anesthetic toxicity
Focal cortical seizure
Localized to a particular focal region -Can be sensory or motor -usually no LOC
What will you see on the screen with long axis imaging?
Long access will see everything axis Ex: if doing an US on radial artery, will show up as a LINE
what will you see in a block/lesion to the median nerve ?
Median (C 5 -T1) at Elbow. Pronation of radioulnar joints. *"Ape Hand"*- thumb hyper extended and adducted - thenar muscles. Weakened opposition of thumb - thenar muscles. Sensory Deficit-Radial portion of palm; palmar surface & tips of radial 31/2 digits [a lot times injury is due to antecubital IV sticks]
This nerve is derived from both the lateral and medial cords. Motor innervation is to most of the flexors muscles in the forearm and intrinsic muscles of the thumb (thenar muscles). Sensory innervation is from the lateral ( radial) 3 & 1/2 digits ( the thumb and first 2 and 1/2 fingers).
Median nerve [Unopposable thumb. 'Ape hand']
A gamma peripheral nerve fibers
Medium myelination Function: skeletal muscle tone Diameter: 3 to 6 µm Velocity: Medium Block onset: third
A-delta Nerve Fiber -Myelination -Function -Diameter -Conduction velocity -Block onset
Medium myelination Function: Fast pain, Temperature, Touch 2 - 5 +++ 3rd Delta flight, how lucky am I? A *medium*-sized person is to my right. *2-5* hours, no room for my feet, my neck hurts (pain), I'm cold (temp), this kid won't stop *touching* my seat. *3rd* to depart, it breaks my heart...oh when oh when will my vacation start?
A-gamma Nerve Fiber -Myelination -Function -Diameter -Conduction velocity -Block onset
Medium myelination Function: Skeletal muscle - tone 3 - 6 +++ 3rd
Which peripheral mechanoreceptors are responsible for two-point discriminative touch and vibration?
Meissner's corpuscles *Double Es for two point discrimination and double S for vibration*
Dorsal column peripheral receptors
Meissner's corpuscles= 2 point discriminative touch, vibration Merkel's discs= Continuous touch Ruffini's Endings= proprioception, prolonged touch and pressure Pacinian corpuscles= vibration
Hippocampus functions
Memory and learning -Structure of the cerebral hemisphere "University campus for memory and learning"
Which peripheral mechanoreceptors are responsible for continuous touch?
Merkel's discs *Angela Merkel is continuously in power
In patients with seizure disorders, what drugs increase EEG activity and can help determine the location of seizure foci during cortical mapping?
Methohexital, etomidate, and alfentanil
4 structures in the brainstem
Midbrain Pons Medulla Reticular activating system
Brainstem
Midbrain: auditory and visual tracts Pons: autonomic integration Medulla: autonomic integration Reticular activating system: controls consciousness, arousal, and sleep
effect of epidural opioids on breast milk
Minimal
Systolic murmur heard over 5th intercostal space and MCL. What type of valvular disease would one expect?
Mitral regurgitation
What (2) increase after placement of an infra-renal aortic cross clamp?
Mixed venous oxygen saturation Preload
*Lipophilic* Opioids: Systemic absorption
More
Urinary retention with opioids
More common in young males More common with neuraxial opiates Inhibition of sacral parasympathetic tone Bladder detrusor muscle relaxed, urinary sphincter contracts Reversed with the naloxone
From most Hydrophilic to Lipophilic opioids
Morphine > Hydromorphone > Meperidine > Fentanyl > Sufentanil
Branches
Most Alcoholics Must Really Urinate Musculocutaneous: C5-C7 -> lateral cord Axillary: C5-C6 -> Posterior cord Median: C5-T1 -> Lateral & medial cord Radial: C5-T1 -> Posterior cord Ulnar: C8 - T1 -> Medial cord
What is the primary determinant of spread for epidural anesthesia?
VOLUME
Corticospinal tract (Motor)
Most important motor pathway Also known as the pyramidal tract Pyramids are formed by the corticospinal neurons as they run through the medulla All toher motor tracts are called extrapyramidal b/c they don't pass through the pyramids
Artery of Adamkiewicz
Most important radicular artery Perfuses the anterior spinal cord in the thoracolumbar region Most commonly originates on the left side b/w T11-12 In 75% of the population it arises from T8-12 In another 10% it arises from L1-2
what is the interscalene block used for?
Most suitable for procedures on the upper arm or shoulder
Volatile anesthetics usually provide enough:
Muscle relaxation for procedures- working on ventral
Late signs of MH
Muscle rigidity, cola-colored urine, coagulopathy, irregular heart rhythm
Myotome
Muscles innervated by ventral nerve roots
Which nerve is most likely to be missed with an axillary block?
Musculocutaneous
what will you see in a block/lesion to the Musculocutaneous nerve ?
Musculocutaneous C 5,6,(7)Very weak flexion of elbow joint- Biceps & Brachialis. Sensory deficit-Lateral Forearm *"unmuscular"*
This nerve is derived from the lateral cord. This nerve innervates the muscles in the flexor compartment of the arm. Carries sensation from the lateral (radial) side of the forearm.
Musculocutaneous nerve [allows you to flex]
The _______________ nerve is most likely to be missed during an *axillary block*.
Musculocutaneous nerve (most often needs to be blocked separately)
Eaton-Lambert syndrome is also called...
Myasthenic syndrome and Lambert-Eaton myasthenic syndrome (LEMS) *Boards will try to confuse you with terms- don't confuse this with myasthenia gravis*
Spinal anesthesia site of action
Myelinated preganglionic fibers of the spinal nerve roots superficial layers of the spinal cord
When used as part of a balanced anesthetic, cardiovascular effects of nitrous oxide include (2)?
Myocardial depression Increased BP (activates SNS, increases SVR, BP, HR)
What does etomidate cause?
Myoclonus, but not asso. with increased EEG activity in pts that don't have epilepsy
Bier Block: < 20 min since LA injection. Can you deflate cuff?
NO
Is a *spinal* safe in the patient w/ MS?
NO SAB = symptom exacerbation in MS patient
Do neuraxial opioids cause: - sympathectomy? - skeletal muscle weakness? - changes in proprioception?
NO to all!
The *saphenous n.* provides MOTOR innervation to what structures?
NONE
Hydromorphone Intrathecal dose: Epidural dose: Epidural Infusion dose:
NOT APPLICABLE 0.5 - 1 mg 0.1 - 0.2 mg/hr
Anesthetic considerations hypokalemic periodic paralysis What not to administer? What is okay to administer?
NOT:Avoid glucose-containing solutions, potassium-wasting diuretics, and beta-2 agonists Okay: **Succinylcholine, NDNMB, Acetazolamide ** controversial- not bc of a K+ shift, but bc there is a possible link between hypokalemic PP and malignant hyperthermia
The *lateral femoral cutaneous n.* provides MOTOR innervation to _____________.
NOTHING
The *posterior femoral cutaneous n.* provides MOTOR innervation to ____________
NOTHING
Channel dysfxn associated w/ Hyperkalemic periodic paralysis
Na+ channelopathy
Neck complications with prone position and scoliosis
Neck rotation -> vertebral compression -> cerebral hypoperfusion
Field Block of musculocutaneous
Needle: 22g, 1 ½ inch Insert needle above artery towards coracobrachial muscle (pinch the belly) Illicit parasthesia (bicep) 5-8cc of local
Neurogenic shock VS Hypovolemic shock
Neurogenic: bradycardia, HoTN and pink/warm extremities Hypovolemic: tachycardia, HoTN and cool/clammy extremities
What is the functional unit of the nervous system? -Primary role?
Neuron - receives and sends information
The brain is made up of 2 types of cells. What are they?
Neurons and Glial cells
What causes cauda equina syndrome (CES)?
Neurotoxicity is the result of exposure to *high concentrations* of LA
What is the only CCB shown to reduce M+M with vasospasm?
Nimodipine Does not relieve the spasm - increases collateral blood flow
Vasospasm prevention / treatment
Nimodipine Triple H therapy: hemodilution (HCT 27-30), hypervolemia, hypertension) daily transcranial doppler exams Maintain CPP Liberal hydration: supports MAP & CPP, causes hemodilution which decreases blood viscosity and cerebrovascular resistance
Bourdon pressure gauge can be used to calculate the cylinder volume for (2)
Nitrogen and helium - they exist as gas in the cylinder
Is there an increased risk of MH w/ osteogenesis imperfecta?
No
Is there 2 point discrimination with the anterolateral system?
No medial leminiscal is two point discrimination
Is Horner's Syndrome a bad thing?
No - it indicates a successful block
C dorsal root peripheral nerve fibers
No Myelination Function: slow pain, Temperature, touch diameter: 0.4 - 1.2 µm Velocity: slowest Block onsets: the second
epidural differential block
No autonomic differential block sensory is 2-4 dermatomes higher than motor
C Nerve Fiber (dorsal root) -Myelination -Function -Diameter -Conduction velocity -Block onset
No myelination Function: Slow pain, Temperature, Touch 0.4 - 1.2 + 2nd Damn (Dorsal and Delta go together) I'm not flying Delta - Slow flight, Cold flight, Touching me
A patient with minor head trauma does not require a head CT if they meet what criteria?
No physical evidence of trauma above clavicles, no headache, no N/V, no neuro deficit, no intoxication or seizures, age <60
Guillain-Barre Anesthetic mgmt
No succ - risk of hyperkalemia Increased sensitivity of nondepolarizers ANS dysfxn -> hemodynamic instability exaggerated response to indirect sympathomimetics (upregulation of postjunctional adrenergic receptors) Immobility -> increased risk of DVT Regional anesthesia is controversial
Should you withdraw the catheter through the epidural needle?
No, it can shear the catheter leaving fragments inside the pt
Is supraclavicular block associated with phrenic nerve involvement?
No.
s/s of toxicity
Numbness of Mouth/tongue Lightheadedness Tinnitus Visual disturbances Irrational behavior Muscle twitching Unconsciousness Generalized Convulsions Coma Death
myasthenia gravis
Normal Ach production, autoimmune related antibodies (IgG) destroy receptors on the neuromuscular jxn Symptoms become worse later in the day or w/ exercise, get better w/ rest thymus gland plays a key role and its removal can improve condition
Number and label cranial nerves
Numbers and Names
Which muscles are not affected in ALS?
Ocular muscles Sensation remains intact
Cranial Nerve III -Nerve name -Function -Bedside test
Oculomotor Motor Eye movement and pupil constriction 3 - eye lashes so all movement
What is the interscalene groove?
On lateral border of sternocleoidmastoid muscle
What ligaments are transversed w/ the paramedian approach
Only the ligamentum flavum
Which (3) axes must be aligned to ensure the best chance for successful laryngoscopy and intubation?
Oral (OA) Pharyngeal (PA) Laryngeal (LA)
What CANNOT treat PDPH?
Opioids
Cranial Nerve II -Nerve name -Function -Bedside test
Optic Sensory Vision
Cranial nerve most likely to be affected by a pituitary tumor
Optic nerve
Side effects of levodopa
Orthostatic hypotension. Common early in therapy
Does the needle size matter in the out of plane approach?
Out of plane approach: Needle diameter would not matter, since the needle is not visualized with this technique
What area of the EKG conicides with the "a" wave of the CVP waveform?
P wave respresents atrial depolarization. The "a" wave on CVP represents atrial contraction
Boyle's Law
P1V1=P2V2 temperature is constant volume and pressure are indirectly proportional to each other
What is the one exception of hyperbaric solutions containing dexrose?
PROcaine 10% in water (lots of molecules)
Which lab value is prolonged in the patient with hemophilia A?
PTT only. Factor 8 deficiency
PaO2 effect on CBP
PaO2 < 50-60mmHg causes cerebral vasodilation and increases CBF (edema). When PaO2 is > 60mmHg it has no effect on CBF
Which peripheral mechanoreceptors are responsible for vibration only?
Pacinian corpuscles "pacific ocean earthquake vibrations"
Lateral spinothalamic tract is responsible for what sensation?
Pain and temperature
Doppler ultrasound technique for supraclavicular block
Palpate the Subclavian artery or position the ultrasound probe at the middle of the clavicle find the artery on Ultrasound just lateral will see a bundle of grapes then BAM.
LOWER Risk Factors for PDPH
Patient Factors - old - non-pregnant - male Provider Factors - pencil-point tip needle - small diameter needle - one dural puncture - using fluid for LOR needle parallel to long axis of meninges - continuous spinal cath (if placed after wet tap)
Artery of Adamkiewicz where does it perfuse? (most important)
Perfuses the anterior spinal cord in the thoracolumbar region
RA cardiac complications
Pericardial effusion or tamponade Aortic regurgitation d/t dilated Aortic root Valvular fibrosis Coronary artery arteritis
Cardiac complications of RA
Pericardial effusion or tamponade Restrictive pericarditis Aortic regurg Valvular fibrosis Coronary artery arteritis
CV complications of SLE
Pericarditis Raynaud's syndrome Hypertension Conduction defects Endocarditis
CV complications of SLE
Pericarditis (tamponade is uncommon) Raynaud's HTN Conduction defects Endocarditis
Nervous system complications from RA
Peripheral neuropathy d/t nerve entrapment
Nervous system complications of RA
Peripheral neuropathy d/t nerve entrapment
Acute treatment of status epilepticus
Phenobarbital, thiopental, phenytoin, benzos, propofol, possibly GA
Treatment for tetanus includes all of the following except: (antitoxin, debridement of the infected area, phenylephrine, intubation)
Phenylephrine
Interscalene Complications
Phrenic nerve paralysis (COPD) Horner's syndrome (Stellate ganglion - C7) Epidural/spinal (needle too medial) Seizures (vertebral artery) C6 neuropathy (intraneural inj) RLN injury (hoarseness) Pneumo (cupola of lung higher on R) Hypotensive bradycardia episode(Bezold Jarish reflex d/t sitting position)
Relative Contraindications to Caudal blocks
Pilonidal cyst abnormal superficial landmarks Hydrocephalus Intracranial tumor Progressive degeneration of neuropathy
Relative contraindications to caudal anesthesia
Pilonidal cyst Abnormal superficial landmarks Hydrocephalus Intracranial tumor Progressive degenerative neuropathy
how do you check the median nerve and what pt. action will you see?
Pinch and Index finger
how do you check the ulnar nerve and what pt. action will you see?
Pinch and fifth digit
Pulmonary complication of RA?
Pleural effusion Restrictive ventilation pattern -Diffuse interstitial fibrosis -Costochondral involvement limits chest wall expansion
Pulmonary complications of RA
Pleural effusion Restrictive ventilatory pattern -Diffuse interstitial fibrosis -Costochondral involvement limits chest wall expansion
What can nitrous oxide cause in patient with TBI?
Pneumocephalus
What is a risk of doing a supraclavicular block?
Pneumothorax from hitting the apex of the lungs
Secondary signs of Parkinson's
Psychosis, depression, dementia, lack of facial expression, diaphragmatic spasm, oculogyric crisis
Which procedures are NOT well suited for an *infraclavicular block*?
Procedures involving SHOULDER or UPPER ARM
Neuraxial recommendations w/ NSAIDs
Proceed w/ neuraxial anesthesia if pt is not on any other blood thinners and has normal clotting mechanisms
Where is CSF produced and reabsorbed
Produced: Choroid plexus Reabsorbed: Arachnoid villi
T12 sensory innervation
Pubic symphysis
In which circumstances is supplemental oxygen LEAST likely to increase arterial oxygenation?
Pulmonary edema
What are (2) examples of instrinsic restrictive lung disease?
Pulmonary edema Aspiration pneumonia Acute Intrinsic= caused by fluid moving into the interstitial space of the pulmonary parenchyma.
Pathophysiology of the PDPH
Punctured dura --> CSF leak from subarachnoid space CSF pressure lost --> cerebral vessels dilate + Brainstem sags into foramen magnum --> stretches meninges, pulls on tentorium
What occurs with extravasation or arterial injection of phenytoin?
Purple glove syndrome Fosphenytoin avoids this risk
Testing branches of the brachial plexus
PusheR, Pull-eM, Pinch ME, Pinch U Radial: Extend arm against resistance Musculocutaneous: Flex arm against resistance Median: Pinch web b/w thumb and index finger Ulner: Pinch pinky finger
What can you use with succs in a patient with myasthenia gravis?
Pyridostigmine- impairs the efficacy of pseudocholinesterase- prolongs duration of succs
The posterior branch of the *femoral n.* innervates the ______________muscles, _____________ joint, and _______________ ligament.
QUADRICEPS (muscles) KNEE (joint) MEDIAL (ligament)
Cutting tip needles
Quincke Pitkin Pros: requires less force Cons: -higher risk of Post dural puncture headache -Less tactile feel -Needle more easily deflected -More likely to injure cauda equina
Cutting tip needle
Quinke Pitkin Requires less force
Which technique is best avoided in the patient with a known difficult airway?
RSI use the predicted difficult airway algorithm
Central nervous system neuraxial analgesia effects
Reduces sensory input to the reticular activating system causes drowsiness
what will you see in a block/lesion to the radial nerve ?
Radial (C5-T1)-*Drop Wrist* - Extensor carpi radialis longus & brevis, Ext. carpi ulnaris. *Difficult to make a fist* Sensory Deficit-Posterior lateral &arm; dorsum of hand index to thumb
This nerve is also derived from the posterior cord. Called "Great Extensor Nerve" because it innervates the extensor muscles of the elbow, wrist and fingers. Sensory innervation is from the skin on the dorsum of the hand on the radial side.
Radial nerve [hand/wrist drop]
What is the anatomic landmark of a *radial n.* at the wrist?
Radial styloid
Acceptable response to twitch monitor (axillary)
Radial: finger or wrist extension Ulnar: ulnar deviation Median: finger flexion Musculocutaneous: bicep twitch
Epinephrine 1:200,000 (5mcg/mL) use does what to LAs?
Reduces vascular uptake of LA and extends block duration
Respiratory effects of neuraxial analgesia
Reduced accessory muscle function Loss of pro perception Apnea results from cerebral hypoperfusion Not result of a phrenic nerve paralysis
Neuroendocrine effects of neuraxial analgesia
Reduces catecholamines, Renin, glucose, thyroid stimulating hormone, growth hormone
Paleocerebellum
Regulates muscle tone -Structure of cerebellum "Paleo diet muscles"
Which devices reduce gas pressure between an oxygen E cylinder and the intermediate pressure system?
Regulator
What does the presynaptic terminal do?
Releases neurotransmitters
Renal complications from RA
Renal insufficiency d/t vasculitis and NSAIDs
What is the 1 PRO of cutting tip spinal needles (Quincke + Pitkin)?
Requires less force
What is the 1 CON of cutting tip spinal needles (Whitacre, Sprotte, Pencan, Greene)?
Requires more force
Most common cause of death with ALS
Respiratory failure
Which peripheral mechanoreceptors are responsible for proprioception and prolonged touch and pressure?
Ruffini's endings
The *posterior femoral cutaneous n.* arises from ______________.
S1 - S3
The posterior femoral cutaneous n. arises from ______________.
S1 - S3
ADULT Dural Sac
S2
INFANT Dural Sac
S3
Sacral hiatus
S5 covered by sacrococcygeal ligament Entry points to epidural space
*Lumbar Plexus* In the Leg
Saphenous n.
Which cells form the myelin sheath in the PNS?
Schwann cells (myelinated beans that get skipped- in periphery)
The _________________ nerve is the biggest nerve in the body.
Sciatic
*Sacral Plexus* Primary Nerves
Sciatic and Posterior Femoral Cutaneous
*Sacral Plexus* In the Leg
Sciatic n. gives rise to: - Common peroneal n. - Tibial n.
What nerve is targeted with a *popliteal block*?
Sciatic n. in the proximal popliteal fossa
C7 sensory innervation
Second and third digits
Misc neuraxial opioids: Sedation is ___ dependent, but most common with _____ Opioids have _______ effect by increasing_______ release Opioid that enters systemic circulation can cross the _______ and enter____ Transfer of opioids from epidural space to _______ is minimal
Sedation is dose dependent, but most common with sufentanil Opioids have antidiuretic effect by increasing vasopressin release Opioid that enters systemic circulation can cross the placenta and enter the fetus Transfer of opioids from epidural space to breast milk is minimal
Status epilepticus
Seizure activity that lasts >30 minutes, or 2 grand mal seizures without regaining consciousness in between
Local anesthetics reduce ________, but proper regional anesthetic does not ___________
Seizure threshold; increase risk of seizures
What causes the BBB to dysfunction
Sites of tumors, injury, infection, or ischemia
Eye complications from RA
Sjogren's sydrome - risk of corneal abrasion
Eye complications of RA
Sjogren's syndrome - risk for corneal abrasion
Key feature of myasthenia gravis
Skeletal muscle weakness that becomes worse later in the day or develops with exercise
From skin to spinal cord
Skin Subcutaneous tissue Supraspinous ligament Interspinous ligament ligamentum flavum (epidural space) dura mater (subdural space) arachnoid mater (subarachnoid space) pia mater spinal cord
Anesthetic mgmt for DMD
TIVA, no succ
Events that cause autonomic hyperreflexia
Stimulation of bladder, bowel, or uterus Bladder catheterization surgery (esp. cystoscopy or colonoscopy) Bowel movement Cutaneous stimulation Childbirth
Is the axillary nerve included in an *axillary block*?
Strangely, no!
Most common culprit responsible for post spinal bacterial meningitis
Streptococcus viridans Found in the mouth, Critical to wear mask
Nervous system complications of SLE
Stroke Psychosis, dementia Peripheral neuropathy
Nervous system complications of SLE
Stroke Psychosis/dementia Peripheral neuropathy
In the adult, new onset seizures are usually the result of...
Structural brain lesion -tumor, head trauma, cerebrovascular event Metabolic cause -hypoglycemia, drug toxicity, withdrawal, or infection
Cause of new onset seizures in adulthood
Structural brain lesion: tumor, head trauma, CVA Metabolic cause: hypoglycemia, drug toxicity, withdrawal, infx
Where does arterial bleeding usually occur in the brain?
Subarachnoid (between arachnoid and pia)
Increased transmural pressure predisposes the aneurysm to rupture- as the vessel bursts where does the blood go?
Subarachnoid space
dural sac
Subarachnoid space terminates In the adults: S2 In the infants: S3
Where does venous bleeding usually occur in the brain?
Subdural space (between dura and arachnoid)
What happens when you accidentally inject LA into the subdural space during an subarachnoid block? What about an epidural?
Subdural space is a potential space between dura and arachnoid mater Spinal dose --> failed spinal Epidural dose --> high spinal w/ delayed onset (15-20 min) (epidural dose into subdural space)
*Hydrophilic* Opioids: Site of action
Substantia gelatinosa Rexed lamina II & III
*Lipophilic* Opioids: Site of action
Substantia gelatinosa Rexed lamina II & III Systemic
Identify substantia gelatinosa on the left side of the spinal cord?
Substantia gelatinosa resides in rexed laminae II and III in the dorsal horn.
What factors increase the risk of contracture in Myotonic Dystrophy
Succ Anticholinesterase reversal Hypothermia (shivering)
Meds to avoid w/ hypokalemic periodic paralysis
Succ Potasium containing solutions (LR)
Meds that are safe with hypokalemic periodic paralysis
Succ??? NDNMB's Acetazolamide
What drugs are safe to administer in the patient with a history of acute intermittent porphyria (2)?
Succinylcholine Nitrous oxide Avoid all barbiturates and etomidate.
Sedation most common with which opioid
Sufentanil
What procedures work best with a *supraclavicular block*?
Supraclavicular block targets trunks/divisions of brachial plexus Best for surgeries AT or BELOW elbow
Patient has remained in ankles crossed position for several hours following induction of anesthesia. Which nerves are at the highest risk of injury? (2)
Sural Superficial peroneal
Consequences of increased intracellular calcium in the myocyte with MH
Sustained muscle contraction-->rigidity Depletion of ATP Increased O2 consumption and CO2/heat production Respiratory (Increased CO2) and lactic acidosis Leakage of potassium and myoglobin into circulation
Autonomic hyperreflexia (dysreflexia)
Sympathectomy above the level of the injury (bradycardia, hypotension) HTN below the level of the injury - further lowers HR d/t baroreceptor reflex 85% of patients w/ injury above T6 will develop AH
What are the CV effects of neuraxial anesthesia? -Sympathectomy causes -Side effects -Treatment
Sympathectomy vasodilates art + ven circulations, but predominantly affects venous capacitance vessels Dec. venous return, CO, BP Volume loading w/ 15mL/kg + vasopressors will minimize HoTN
Autonomic hyperreflexia is unlikely to occur in patients with injury below...
T10
Caudal approach to epidural space is useful for procedures requiring up to:
T10 sensory block (Covers sacral, lumbar, lower thoracic dermatomes)
Up to 85% of patients with an injury above _______ will develop autonomic hyperreflexia
T6 The higher the level of injury, the more intense the response
In 75% of the population, the artery of Adamkiewicz originates between...
T8-T12
Describe train of four monitoring for the patient with hemiparesis?
TOF monitoring on the hemiparetic limb yields a falsely elevated response(meaning false high for relaxation). On the affected side there are extrajunctional receptors at the NMJ as well as on the sarcolema. Decreased sensitivity to Nondepolarizers.
Neuraxial recommendations w/ Thrombolytic agents
TPA, streptokinase, alteplase, urokinase Absolute contraindication to neuraxial anesthesia
Early signs of MH
Tachycardia Tachypnea ↑ EtCO2 Masseter spasm Irregular heart rhythm warm soda lime
Sign of seizure under general anesthesia
Tachycardia, HTN, ↑EtCO2 (d/t ↑O2 consumption)
S/sx of seizures while under GA
Tachycardia, hypertension, increased ETCO2
Early signs of MH
Tachycardia, tachypnea, masseter spasm, warm sodalime, irregular heart rhythm
Examples of Cholinesterase Inhibitors
Tacrine Donepezil (Aricept) Rivastigmine (Exelon) Galantamine (Razadyne)
General presentation of a patient with Marfan's
Tall with pectus excavatum (sunken chest), kyphoscoliosis, and hyperflexible joints (carful with positioning)
What can resemble nerves on an US?
Tendons and ligaments
Myasthenic Crisis vs. Cholinergic Crisis
Tensilon Test: Administer 1-2mg IV edrophonium -if muscle weakness gets worse than its a cholinergic crisis, and the pt should get an anticholinergic -if muscle weakness improves than its myasthenic crisis
Diencephalon contains...
Thalamus and hypothalamus
Diencephalon
Thalamus: acts as a relay station that directs information to different cortical structures Hypothalamus: primary neurohumoral organ
cerebral autoregulation
The ability of the brain to maintain constant cerebral blood flow despite changes in systemic arterial pressure over a range of 50 to 150 mm Hg Benefit: Ensures that the brain has a steady supply of oxygen and substrates in the face of blood pressure fluctuations.
what do a cross-section of peripheral nerves look like?
The characteristic appearance of a peripheral nerve, in ideal ultrasound cross section, looks like a bundle of drinking straws viewed end-on (Honeycomb) -Nerves generally run along borders of other structures especially between different muscle groups.
What is the first landmark for the axial brachial plexus block?
The first landmark to look for is the brachial artery which lies near the surface.
Where do most CNS tumors arise from?
The glia
AXILLARY BRACHIAL PLEXUS BLOCK
The goal is to deposit local anesthetic around the axillary artery. Sometimes, a single injection is sufficient to spread in a "doughnut" shape around the artery. Placing a small amount of local anesthetic solution (3-8 ml) at each nerve location will cause almost immediate anesthesia over their respective areas of innervation. Local anesthetic should also be injected adjacent to the musculocutaneous nerve.
What is the consequence of using more than 5mL volume of LA to block *ulnar n.* at the elbow?
Too much volume = compress ulnar nerve, resulting in ischemic injury
Risks of wake up test
Tracheal extubation Removal of IV & art line access Air embolism Awareness Pain Damage to surgical instrumentation
polyhydraminos should raise suspicion for?
Tracheosophageal Fistula TEF is the letter "T" in the VATER and VACTREL associations
dorsal column-medial lemniscal pathway
Transmits fine touch, proprioception, vibration, and pressure 2-point discrimination = high degree of localizing the stimulus large, myelinated, rapidly conducting fibers transmits sensory information faster than anterolateral system
Anterolateral system - Spinothalamic tract
Transmits pain, temperature, crude touch, tickle, itch, and sexual sensation Smaller, myelinated, slower conducting fibers Transmits sensory information 1/3-2/3 times slower than dorsal column No 2 point discrimination
What is the preferred method for following a nerve along it's course?
Transverse scanning by sliding a broad linear transducer *Transducer manipulation plays a major role in optimizing nerve imaging*
Unacceptable response to nerve stimulator (interscalene)
Trapezius Diaphragm (hiccup)
When should steroids not be given?
Traumatic brain injury
Interspinous ligament
Travels adjacent to And joins the Spinous processes
Posterior longitudinal ligament
Travels on posterior surface of the vertebral body
How can we improve outcomes for out of hospital VF anoxic brain injury patients?
Treatment: mild hypothermia (32-34C) for 12-24 hours -Decreases CMRO2 and can improve outcomes of anoxic brain injury patients
If a patient becomes hypotensive after a hyperbaric spinal, which position do you want to avoid?
Trendelenburg to avoid high spinal
Cranial Nerve V -Nerve name -Function -Bedside test
Trigeminal -VI: ophthalmic -V2: Maxillary -V3: Mandibular Both Somatic sensation to face Somatic sensation to anterior 2/3 tongue Muscles of mastication
What is tic doulureaux? What nerve is affected?
Trigeminal neuralgia CN 5 Excruciating neuropathic pain in the face
Trismus vs Masseter muscle rigidity
Trismus = jaw is tight but can still be opened (normal reaction succ) Masseter = jaw cannot be opened (not corrected by NMB, b/c its an increase in intracellular Ca+) If pt has masseter spasm, assume MH
Trismus vs. masseter spasm
Trismus = tight jaw that can still be opened Masseter muscle rigidity = jaw that cannot be opened
Trismus is a normal response to________ Is it okay to proceed?
Trismus is normal response to succinylcholine Okay to proceed if the trismus occurs in isolation- should consider converting to non triggering agents
Cranial Nerve IV -Nerve name -Function -Bedside test
Trochlear Motor Eye Movement down and center
Femoral Nerve Block Ultrasound Image
VAN
When properly placed the distal tip of the LMA sits at the?
cricopharyngeus muscle (upper esophageal sphincter)
The anterior branch of the *femoral n.* innervates the ______________ surface of the thigh and the ______________ muscle.
VENTRAL (surface) SARTORIUS (muscle)
IV regional anesthesia of the LOWER extremity: Tourniquet inflation pressure if placed on upper leg If the tourniquet is placed on the CALF LA volume Inflation pressure Make sure it does not compress
Upper leg 350-400mmhg; large volume of LA Lower leg/calf LA volume and tourniquet inflation pressure same as upper extremities **Make sure it does not compress peroneal nerve near head of fibula
ALS S/S
Upper neuron: spasticity, hyperreflexia, loss of coordination Lower neuron: muscle weakness, fasciculations, and atrophy Often begins in hands: spreads to tongue, pharynx, larynx, and chest does not affect ocular muscles Orthostatic hypotension, resting tachycardia sensation is intact respiratory failure is most common cause of death
What is the most common comorbidity in children presenting for surgery?
Upper respiratory tract infection
What indices suggest a prerenal cause of oliguria (2)
Urine sodium <20mEq/L Fractional excretion of sodium <1% Decreased RBF causes concentrated urine (increased osmolality and low FE of sodium.
Beir block use and rule of two
Use for foreign body exploration, tendon and joint repair, and repair of lacerations Rule of Two: Two Ivs Two Tourniquets Twenty Minutes Min Two hours max
Late respiratory complications of scoliosis
V/Q mismatching Hypoxemia Hypercarbia (signs of impending failure) Pulmonary hypertension reduced response to hypercapnia Cor pulmonale Cardiorespiratory failure
List the 3 branches of CN V and function
V1: Opthamalic V2: Maxillary V3: Mandibular Somatic sensation to face, Somatic sensation to anterior 2/3 of tongue, muscles of mastication
The sitting position for DBS increases the risk for: If detected the patient should not: What needs to happen if detected?
VAE if VAE detected, pt should not take a deep breath Have surgeon flood field with NS
Late respiratory complications with scoliosis
VQ mismatching Hypoxemia Hypercarbia (sign of impeding failure) Pulmonary HTN, cor pulmonale Reduced response to hypercarbia Cardiorespiratory failure
Infraclavicular block complications:
Vascular puncture- axillary artery and vein are right there Higher incidence of chylothorax Pneumothorax-if needle is too medial *infra has lower incidence of pneumo, stellate ganglion block, phrenic nerve block compared to interscalene and supraclavic
Choose the BEST (2) NMB for the patient with hypertrophic cardiomyopathy?
Vecuronium and Rocuronium (NOT pancuronium it increases HR, not atracurium in releases histamine)
Venous air embolism increases ___ and reduces ___ -What aids in aspiration of entrained air?
Venous air embolism increases dead space and reduces EtCO2 (increased PaCO2 - EtCO2 gradient) -Central line
Cause of ischemic optic neuropathy
Venous congestion in the optic canal reduces perfusion pressure, causing ischemia of the optic nerve Increased intraabdominal and intrathoracic pressure can also increase IOP Ocular perfusion pressure= MAP- Intraocular pressure
Ventral corticospinal tract -What does it innervate? -Where does it cross over?
Ventral corticospinal tract: Fibers that innervate axial muscles remain on the ipsilateral side as they descend this tract -Most cross to the contralateral side when they reach the cervical or upper thoracic area in the spinal cord
Volatile anesthetics cause skeletal muscle relaxation by acting where in the spinal cord?
Ventral horn- so can use gas and potentially eliminate the use of NMB in myasthenia gravis
Where do motor and autonomic neurons exit the spinal cord?
Ventral root
Lateral border of the epidural space
Vertebral pedicles
Which arteries supply the posterior circulation of the brain? Order?
Vertebrals Aorta-->Subclavian a.-->Verterbral a.--> Basilar a.--> Posterior fossa structures and cervical spinal cord
Inverse Steal (Robin Hood, Reverse Steal):
When the patient with an ischemic region of brain is hyperventilated such that PaCO2 falls, blood vessels in non-ischemic brain constrict and blood is diverted to ischemic brain which vessels are already maximally dilated. This theory does not seem to work clinically
Can autonomic hyperreflexia occur postoperativly?
Yes - may present as the effects of anesthesia wear off -Close postoperative monitoring is warranted
Interscalene anatomy 2 [image]
Will only line up like a traffic light is @ about C6
What do you see on the in plane approach?
With this approach, one can see the needle approach the target. However, be aware that it is easy to be a little oblique, and to not actually see the needle tip.
Duschenne Muscular Dystrophy
X-linked recessive disease where cells do not make dystrophin. The lack of dystrophin destabilizes the sarcolemma during muscle contraction and increases membrane permeability. Extracelluar Ca+ enters cells (↑metabolism) Intracellular K+ (cardiac arrest) & myoglobin (renal failure) leave the cell Normal RyR1 receptor
T6 sensory innervation
Xiphoid process
Is an *epidural* safe in the patient w/ MS?
YES
Does US improve success rate?
Yes Brachial plexus block: 99% Popliteal fossa: 89.2% -Around all the nerves is a fascial plane (structure that holds things together). With ultrasound you can see LA/medication go around/cover the fascial plane.
Can you use an epidural for SCI patients?
Yes - however an epidural does not inhibit the sacral nerve roots to the same degree as a spinal anesthetic
Can the recurrent laryngeal nerve be injured with an interscalene block?
Yes, due to large volume of LA -will present as hoarseness
Is hypertension common after an ischemic stroke?
Yes- elevated bp supports CPP/ cerebral O2
Is this a good block to do on a patient with pre existing respiratory insufficiency?
Yes- far enough away from neuraxial and phrenic nerve (diaphragmatic paralysis rarely occurs)
Should levodopa be given morning of surgery?
Yes- prevents worsening of rigidity which can impact ability to ventilate for long procedures- can give it via gastric tube
Do water soluble drugs require a larger dose in neonatal pharmacokinetics?
Yes. They have a larger Vd
Higher risk of post dural puncture headache
Young age Female Pregnancy cutting tip needle Large diameter needle Air for loss of resistance with epidural needle
Factors that cause higher risk of PDPH
Younger age Female Pregnant Cutting tip needle larger diameter needle using air for LOR syringe Needle perpendicular to long axis of meninges
Hypokalemic periodic paralysis is associated with...
a calcium channelopathy
An ischemic CVA most likely stems from...
a cardio-embolic event, such as a-fib
Effects on intacellular volume a) D5LR b) NS c) D5w
a) D5LR - small dehydrated cell b) NS - normal cell c) D5w - swollen bloated cell
Hyperkalemic periodic paralysis is associated with...
a sodium channelopathy
Match each type of peripheral nerve to its function: a) A alpha b) A beta c) A delta d) A gamma
a) A alpha - Motor b) A beta - pressure c) A delta - temperature d) A gamma - muscle tone (muscle spindles)
Match each disease with underlying pathology a) Addisons disease b) Graves disease c) Conns disease d) Hashimotos disease
a) Addisons disease- hypoadrenalism b) Graves disease- hyperthyroidism c) Conns disease- hyperaldosteronism d) Hashimotos disease- hypothyroidism
Match adrenergic receptor to its most potent drug a) Alpha1 bAlpha2 c)Beta1 d) Dopamine1
a) Alpha1- Norepi bAlpha2- Clonidine c)Beta1- Isoproterenol d) Dopamine1- Fendolopam
Match each cardiac pathophysiology with its characteristic pulse waveform? a) Aortic Stenosis - b) Aortic Regurgitation - c) Cardiac Tamponade - d) Systolic left ventricular failure -
a) Aortic Stenosis - Pulsus parvus b) Aortic Regurgitation - Bisferiens pulse c) Cardiac Tamponade - Pulsus paradoxus d) Systolic left ventricular failure - Pulsus alternans
Describe each mode of ventilation: a) Assist control ventilation b) pressure control ventilation c) intermittent mandatory ventilation d) controlled mandatory ventilation
a) Assist control ventilation - spontaneous breaths receive full preset Vt b) pressure control ventilation - tidal volume varies with lung compliance c) intermittent mandatory ventilation - traditional weaning mode d) controlled mandatory ventilation - best used for apneic patients
Match each breathing circuit to the number of valves it has: a) Ayres T-piece- b) Jackson Reece- c) Circle breathing system-
a) Ayres T-piece-0 b) Jackson Reece-1 c) Circle breathing system-3
Match each drug with the enzyme or pathway that it inhibits a) Methylene blue b)Etomidate c) Nitrous oxide d) Tranexamic acid
a) Methylene blue - nitric oxide cycle guanylate monophosphate(inhibits the vasodilatory effects of NO in patients with vasoplegia) b)Etomidate - 11 beta hydroxylase (inhibits steroid synthesis) c) Nitrous oxide - Methionine synthase (inhibits vitamin B12 metabolism and DNA synthesis) d) Tranexamic acid - Plasmin (inhibits fibrinolysis to reduce surgical bleeding)
Match the vasodilator with its primary site of action a) Nitroglycerin: b) Prazosin: c) Nitroprusside:
a) Nitroglycerin: venules b) Prazosin: arterioles c) Nitroprusside: arterioles & venules
Match each twitch to its corresponding nerve: a) Plantar flexion b) Patellar twitch c) Adductor twitch d) Dorsiflexion
a) Plantar flexion- tibial nerve b) Patellar twitch- femoral nerve c) Adductor twitch- obturator nerve d) Dorsiflexion- peroneal nerve
Match each hormone to its primary physiologic effect: a) Secretin b) Motilin c) Cholecytokinin d) Gastrin
a) Secretin- stimulates bile flow b) Motilin- stimulates upper GI motility c) Cholecytokinin- stimulates gallbladder contraction d) Gastrin- stimulates pepsinogen secretion
Match each immunosuppressive drug to its best description: a) Tacrolimus b) Antithymocyte globulin c) Cyclosporine d) Azathioprine
a) Tacrolimus- macrolide antibiotic b) Antithymocyte globulin- polyclonal IgG c) Cyclosporine- 11 aminoacid cyclic peptide d) Azathioprine- prodrug that converts to 6 mercaptopurine
Match each region of the adrenal gland with the primary substance it secretes a) Zona glomerulosa b) Zona fasciculata c) Zona reticularis d) Medulla
a) Zona glomerulosa - releases mineralocoritcoids (aldosterone) b) Zona fasciculata - releases glucocorticoids (cortisol) c) Zona reticularis - releases androgens (dehydroepiandrosterone) d) Medulla - catecholamines (epi and norepi)
Identify region of the myocardium that the lead monitors? a) aVL b) V3 c) II
a) aVL - Lateral LV b) V3 - Anterior LV c) II - RV
Match each event to the laboratory test that is used to monitor it a)Coumadin b) heparin infusion c) fibrinolysis d) aspirin
a)Coumadin - PT b) heparin infusion - ACT c) fibrinolysis - Ddimer d) aspirin - bleeding time
Inhaled agents chemical structures a)Halothane b)Isoflurane c)Desflurane d)Sevoflurane
a)Halothane - the only alkane, 1 Cl-, 1Br, 3Fl b)Isoflurane- 5 Fl, 1 Cl c)Desflurane - 6 Fl d)Sevoflurane - 7Fl
Match each type of WBC with statement that describes it: a)Neutrophil- b)basophil- c)B-lymphocyte- d)T-lymphocyte-
a)Neutrophil- most abundant type of WBC b)basophil- releases histamine c)B-lymphocyte- humoral immunity d)T-lymphocyte- cell mediated immunity
What is the constant in each gas law: a)boyle- b) gay-lussac- c)charles-
a)boyle-temperature b) gay-lussac- volume c)charles-pressure
Identify underlying pathophysiology in each musculoskeletal disease a)duchenne muscular dystrophy b)acute idiopathic polyneuritis c) hyperkalemic periodic paralysis d) myotonic dystrophy
a)duchenne muscular dystrophy - absence of dystrophin b)acute idiopathic polyneuritis - immunologic assault on myelin in the peripheral nerve c) hyperkalemic periodic paralysis - alteration of sodium channels d) myotonic dystrophy - excess calcium availability
Match each complication of TURP syndrome with its presentation: a)fluid overload- b)hypoosmolality- c)glycine toxicity-
a)fluid overload- HTN b)hypoosmolality- SZR c)glycine toxicity- transient blindness
GI hormone site of its secretion: a)gastric inhibitory peptide- b)cholecytokinin- c)secretin- d)gastrin-
a)gastric inhibitory peptide-K cells b)cholecytokinin- I cells c)secretin- S cells d)gastrin- G cells
ASA closed claims: source of M&M and incidence a)respiratory events- b)Regional anesthesia- c)equipment failure- d)cardiovascular events-
a)respiratory events- 17% b)Regional anesthesia- 20% c)equipment failure- 10% d)cardiovascular events- 13%
Following retinal detachment surgery, how long should nitrous oxide be avoided? a)silicone oil b)air bubble c)sulfur hexafluoride
a)silicone oil - 0days b)air bubble- 5days c)sulfur hexafluoride- 10days
Divisions
anterior x 3 posterior x 3
Carbamezapine s/e
aplastic anemia Thrombocytopenia Liver dysfunction Leukopenia ADH like effect - hyponatremia
Larson Maneuver
application of pressure to the laryngospasm notch
Cross-sensitivity to latex is high in patients who are allergic to:
avocado, banana, kiwi, melon, mango, papaya, pineapple, potato, tomato, wheat, figs, chestnut, eggplant
Optic nerve circulation
carotid artery -> ophthalmic artery -> central retinal artery central retinal artery occlusion can lead to blindness
Cerebral Salt Wasting (CSW)
excessive renal wasting of sodium and chloride after brain surgery Brain releases natriuretic peptide and this results in hyponatremia caused by salt wasting in the kidneys
Cauda Equina Syndrome cause
exposure to high concentrations of LA
filum terminale
extends from conus medullaris to the coccyx -continuation of the pia mater caudal to the conus medullaris, anchors spinal cord to coccyx
Pia mater
external covering of the spinal cord, should not be punctured during spinal ansthesia
ventral corticospinal tract
fibers that innervate the axial muscles then descend via the ventral corticospinal tract on the ipsilateral side. fibers crossover to the contralateral side of the spinal cord in the cervical or thoracic region
Classic presentation of PDPH
fronto-occipital h/a -may be accompanied by n/v, photophobia, diplopia, and tinnitus -laying supine relieves h/a
In Eaton-Lambert syndrome, the postsynaptic nicotinic receptor...
is present in normal quantity and functions normally
What are oxybarbiturates?
methohexital phenobarbital secobarbital
White matter
myelinated axons - ascending & descending tracts dorsal, lateral and ventral columns
Primary site of local anesthetic action in spinal anesthesia
myelinated preganglionic fibers of the spinal nerve roots
myotome vs dermatome
myotome = ventral nerves dermatome = dorsal nerves
Secondary signs of AH
nasal stuffiness HTN -> H/A & blurred vision Malignant HTN -> Stroke, seizure, LV failure, dysrhythmias, pulmonary edema, and/or MI
What is the epidural space?
nerve roots, fat pads, blood vessels fat cells act as a lipophilic sink for drugs reducing their bioavailability bupivicaine > lidocaine & fentanyl > morphine
Batson's plexus
network of epidural veins that drain venous blood from the spinal cord and meninges. It passes through the lateral and anterior regions of the epidural space.
What does the grey matter contain?
neuronal cell bodies
Grey matter
neuronal cell bodies in the CNS -processing center for afferent signals from the periphery -H shape of the spinal cord
Cauda equina syndrome
neurotoxicity result of High concentrations of local anesthetics 5% lidocaine and Spinal micro catheters Increased risk Bowel and bladder dysfunction, sensory deficits, weakness, paralysis Supportive treatment
Is there contraindication for succs or NDMAs?
no
Epidural anesthesia has ______ autonomic differential block
no Sensory block 2 - 4 dermatomes higher than motor
Anesthetic mgmt of ALS
no benefit of one technique over another Succ can cause lethal hyperkalemia Sensitivity to nondepolarizing NMB's Bulbar muscle dysfxn increases risk of pulmonary aspiration Chest weakness reduces vital capacity & minute ventilation may need postoperative mechanical ventilation
Nausea/vomiting: neuraxial opioids Caused by activation of what?
opioid receptors in the area of postrema of medulla and vestibular apparatus
Lidocaine onset, anesthesia, and analgesia
onset 10-20 min, anesthesia duration 2-5 hrs, analgesia duration 3-8 hrs
Bupivicaine onset, anesthesia, and analgesia
onset 15-30 min, anesthesia duration 4-8 hrs, analgesia duration 12-18 hrs
Hyperkalemic periodic paralysis is present if skeletal muscle weakness follows...
oral potassium administration (weakness occurs after serum potassium is increased)
Autonomic dysfunction in ALS presents as...
orthostatic hypotension and resting tachycardia
Autonomic dysfunction in Eaton-Lambert syndrome causes...
orthostatic hypotension, slowed gastric motility, and urinary retention
Mannitol
osmotic diuretic dose: 0.25 - 1g/kg MOA: increases serum osmolarity which increases pull of water across the BBB if the BBB is disrupted Mannitol enters the brain and increases cerebral edema causes transient increase in overall blood volume, can stress the failing heart
Injury to a lower motor neuron results in....
paralysis on the same side of the body as the injury
injury to lower motor neurons
paralysis on the same side of the body as the injury presents w/ impaired reflexes and flaccid paralysis Babinski sign is absent
If an injury occurs to a upper motor neuron above the level of decussation (cross over) in the medulla...
paralysis will be on the opposite side of the body
If an injury occurs to a upper motor neuron below the level of decussation (cross over) in the medulla...
paralysis will be on the same side of the body
Hyperbaric solution and supine patient
pool in sacrum and thoracic kyphosis
Caregiver characteristics that increase risk of abuse
poverty, unemployment, lack of education, social isolation, single parent, caregiver is unrelated to the child, hsitory of: substance abuse, mental illness, domestic violence, and neglect during their own childhood
CNS affects of neuraxial anesthesia
reduces sensory input to the reticular activating system. This can cause drowsiness
Nerves most likely to be injured as a result of improper lithotomy positioning
sciatic common peroneal posterior tibial saphenous obturator
What happens with Central Retinal Artery Occlusion? What are the symptoms post anesthesia?
the central retinal artery perfuses entire retina and if it becomes occluded it can cause blindness Sudden painless vision loss in one eye upon emergence- fundoscopic exam reveals cherry red macula and surrounding retina appears pale *note there are several branches of the central retinal artery and you can get a partial visual field defect depending on what is occluded
Bell's palsy results from injury to...
the facial nerve (7) -causes ipsilateral facial paralysis