Ultrasound Final Combined with class questions

Which 2 local anesthetics are hydrolyzed to p-Aminobenzoic acid (PABA), which inhibits the action of sulfonamide antibiotics? a. Procaine b. Benzocaine c. Bupivacaine d. Lidocaine

A & B: Procaine and Benzocaine (ester LA)

Which of the following are symptoms of Horner's syndrome. Select all that apply: a. Anhidrosis b. Miosis c. Mydriasis d. Ptosis e. Hyperhidrosis

A, B, and D: Anhidrosis, miosis, and ptosis

What are the factors 1st affected? 2nd? Last? Which recovery quicker?

A-T-P 1st to be blocked Auto/Temp/Pain T-P Touch/pressure M-V-P last to be blocked Motor/vibration/proprioception

What nerve fiber type is considered the least sensitive to local anesthetics (slowest onset)

A-alpha fastest, largest in doses we give Myelinated, large C-sympathetic in vitro only

What peripheral nerve block is the BEST choice to use an adjunct to interscalene blocks for shoulder surgeries? a. Superficial cervical plexus b. Saphenous c. Transabdominal plane d. Fascia Illiaca

A. Superficial cervical plexus

What is the needle approach for an interscalene block? Why?

A: needle approach is in-plane from the lateral-posterior aspect medially and *pointed slightly caudad* a. When performing a paresthesia or nerve stimulation technique, helps to prevent entry into anatomical areas that could result in administration of a central neuraxial block b. Prevents needle from passing transverse processes and entering the paravertebral artery

When performing an Obturator Nerve Block under ultrasound, what three adductor muscles must you identify?

Adductor Longus, Adductor Brevis, Adductor Magnus

Musculocutaneous nerve block: what is the alternative field block at the elbow?

Alternative field block at elbow as the nerve courses superficially at the interepicondylar line. The insertion of the biceps tendon is identified, and a short 22-guage needle is inserted 1-2 cm laterally; 5-10 mL of local anesthetic is then injected as a field block

An interscalene block is typically _____ _______ and therefore is not a good anesthetic choice for a patient having surgery on their ring finger.

An interscalene block is typically ulnar sparing and therefore is not a good anesthetic choice for a patient having surgery on their ring finger.

What would be some reasons to consider a continuous peripheral nerve block instead of a single, long-acting peripheral nerve block?

Anesthesia for surgery and prolonged analgesia postop, prolonged analgesia for patients with significant trauma requiring multiple surgeries, therapeutic treatment for chronic pain syndromes, or pain control for patients during aggressive postop physical therapy or rehabilitation

Where is the phrenic nerve located?

Anterior surface of the anterior scalene muscle

Where does the recurrent laryngeal nerve lie in relation to the SC artery?

Anterior to the subclavian artery

A nurse anesthetist student is attempting an axillary nerve block; what portion of the nerve trunk would they need to effectively anesthetize to provide loss of sensation to the arm? To the hand? Which are affected first?

Arm: Fibers from the Mantle of the nerve -Most proximal and 1st affected Hand: core (core is in the middle and goes more distal)

In administering intercostal nerve block to provide anesthesia on the anterior portion of the chest where does the block need to be placed?

At or posterior to the mid-axillary line (wraps around from the spinal cord & branches)

What 3 nerves branch from the brachial plexus proximal to the axillary block is administered

Axillary, musculocutaneous, medial brachial cutaneous nerves

Does the supraclavicular block reliably anesthetize the axillary and suprascapular nerves?

Axillary-yes Suprascapular-no

When should the axillary block be used? Name the cutaneous nerves spared with the axillary block that branch from the brachial plexus and innervate the medial/inner aspect of the upper arm. What should you do?

Axxillary: procedures distal to the elbow -Intercostobrachial -Medial brachial cutaneous nerve *Block these separately* Musculocutaneous usually requires separate injection

The Lateral Femoral Cutaneous Block is performed through all the following steps EXCEPT: a. A 22-gauge needle is inserted and directed laterally b. Observe a "pop" as needle passes through the fascia iliaca. c. Administer 10-15 ml of LA for the field block d. LA is deposited above and below the fascia

B, Pop felt through the Fascia *Lata*

What type of needle appears to reduce the incidence of nerve trauma? Other advantages?

B-bevel (blunt bevel) needle § blunt tip and smaller cutting edge § helps push nerves aside upon contact § improved feedback (feel tissue planes & fascial compartments)

When performing a posterior lumbar plexus block, why is it better to go closer to the Vertebral column?

Better pain control

Ideally transversus abdominis plane (TAP) blocks are performed by injecting LA where?

Between the fascial layers of the internal oblique an trasversus abdominis muscle

What are the landmarks for identifying the sciatic nerve in subgluteal sciatic block on the ultrasound?

Between the greater trochanter and ischial tuberosity, inferior to the gluteus Maximus, and superior to the quadriceps femoris.

What area of the arm is blocked first? How is this different from the axillary block?

Bier Block: distal portion of extremity is blocked first Axillary Block: distal portion of extremity has a delayed onset whereas the proximal arm has an earlier onset

2 most common local anesthetics infused for continuous nerve block catheters. -What is tachyphylaxis?

Bupivacaine & ropivacaine-some selectivity for sensory nerves & long acting Tachyphylaxis is decreased response to increased drug use

In comparing bupivacaine regarding their toxicity which has the lowest cardiovascular collapse to CNS toxicity dose (CC/CNS) ratio? Bupivacaine vs. lidocaine

Bupivacaine has the lowest CC/CNS ration (3)-see cardiac effects before CNS Lidocaine (7) see CNS effects before cardiovascular CNS SE: Metallic taste, tinnitis, circumoral tingling

Before administering your field block, your instructor stops you and says he would like you to use 2.5mg/kg rather than 3mg/kg for your calculations. Remembering Dr. Ceremuga's and Dr. Craig's lectures on local anesthetics, what is your reasoning for this?

Bupivacaine is very cardiotoxic → it's better to be conservative!

Which nerve fiber type is most sensitive to local anesthetics? Which is least sensitive?

C fiber is most sensitive. Alpha fiber is least sensitive.

All of the following are benefits of epinephrine in conjunction with a local anesthetic except: a. Acts a tracer for IV injection b. Prolongs duration and intensity of blocks c. First choice for "ring like" blocks d. Decreases peak plasma levels

C, false. Rationale: a. TRUE; can be used as a vascular tracker b. TRUE; vasoconstricts the local area and prolongs the duration of the block in the desired area c. FALSE; should never be used for ring like blocks or on distal appendages; cuts off circulation d. TRUE Add epi yourself--premixed are pH adjusted Always use MPF--preservative free!

Any patient who is unable to abduct their arm more than ___ degrees at the shoulder is not an appropriate candidate for an axillary block. a. 120 degrees b. 35 degrees c. 45 degrees d. 75 degrees

C. 45 degrees

Name the field block uses the mastoid process and Chassaignac's tubercle as landmarks. a. Psoas block b. Intercostobrachial Nerve Block c. Superficial Cervical Plexus Block d. Saphenous Nerve Block

C. Superficial cervical plexus block Chassaignac's tubercle is C6 transverse process

The cervical plexus is formed from the anterior rami of C-____. It supplies sensation to what areas?

C1-4 and supplies sensation to the jaw, neck, occiput, and areas of the chest & shoulder

The phrenic nerve arises from what 3 ventral Rami?

C3, C4, C5

What nerve root is shared between the cervical & brachial plexus?

C5

The musculocutaneous nerve runs within which muscle of the upper arm?

Coracobrachialis Muscle

What are the landmarks for an infraclavicular block? 2 approach options

Coracoid process: find the coracoid process and move 2 sonometers medial and two sonometers inferior to find the brachial plexus. Needle entry is perpendicular to the skin. OR 2. Find C6 tubercle (Chassaignac's Tubercle) and draw a line from it to the brachial artery that crosses the midpoint of the clavicle. Brachial plexus located beneath midpoint of clavicle.

What is the nerve stimulation technique for the infraclavicular block?

Coracoid technique: Find the coracoid process, move 2 cm medial and 2 cm caudad

Which division of the brachial plexus is targeted with the infraclavicular block?

Cords: Lateral, Posterior, Medial

Supra vs. interscalene block risks

Decreased risk for palsy + horner syndrome with supraclavicular • Ipsilateral phrenic nerve palsy ↓ • Horner's syndrome ↓ • Recurrent laryngeal nerve palsy ↓ • Pneumothorax and subclavian artery puncture

Which of the following factors has the greatest impact on the onset, duration and intensity of a peripheral nerve block? a. The overall mass of the local anesthetic b. Ester versus amide c. Addition of sodium bicarbonate to the local anesthetic d. Percentage of concentration of the local anesthetic e. Metabolic pathway for elimination from the body

Correct Answer: A. Rationale: a. The *overall mass includes the volume and concentration;* the greater the volume and the stronger the concentration of the LA the faster onset, longer duration and greater intensity of the block b. Affects duration but not onset or intensity c. Sodium bicarb changes the pH and leads to a faster onset; could lead to a shorter duration d. You have to consider the volume given as well, not just the concentration e. Metabolic pathway will affect duration but not intensity or onset

What nerve innervates between the great and second toe, as well as travels under the retinaculum in the ankle?

Deep peroneal

3 nerves that can be blocked with 1 needle in an ankle block

Deep peroneal Superficial peroneal Saphenous nerves

Drawn an arrow & label each of the nerves that would be blocked when administering an ankle block

Deep peroneal nerve Saphenous nerve Posterior tibial nerve (medial)

What is the max TQ time recommendation? What is the minimum?

Deflate tourniquet only when the surgeon is finished • Max tourniquet time recommendation is 1.5-2 hours • Patient may not tolerate tourniquet pain after 1 hour • Never deflate tourniquet less than 20 minutes following LA injection • Consider quickly alternating deflating, inflating, deflating cuffs

The Fascia Iliaca block utilizes landmarks divided into thirds between the ASIS and the pubic tubercle. Which of the following is the correct needle placement landmark in performing this nerve block? a. Proximal 1/3 to the pubic tubercle b. Halfway between the ASIS c. 1 cm Cephalad to the lateral 3rd mark d. 2 cm Cephalad to the lateral 3rd mark

D. 2 cm Cephalad to the lateral 3rd mark

If you were to stimulate the Median Nerve with a Peripheral Nerve Stimulator, what reactions could you see? a. Thumb adduction b. Index finger pulls inward c. Flexion of middle finger d. All of the above

D. All of the above

What muscle(s) attach to the ischial tuberosity? a. Biceps femoris (long head) b. Semitendinosus c. Semimembranosus d. All of the above

D. All of the above

Femoral nerve block stimulation technique

Distinct quadriceps twitch elicited @ current < 0.5mA (visualize patella movement)

Classic approach for infraclavicular BP block

Draw line from C-6 tubercle through midclavicle to brachial artery -Insert needle below clavicle toward the axillary artery pulsation

Differential diagnosis if a patient complains of numbness in the contralateral arm after an interscalene block utilizing PNS technique utilizing a non-insulated needle.

Dural cuff injection to the subarachnoid space

The following are reasons why an elevated PaCO2 level due to over sedation increases the risk for local anesthetic toxicity EXCEPT: a. ↑ PaCO2 increases CBF → ↑ delivery of local anesthetic to the CNS b. ↑ PaCO2 decreases binding sites for LA on serum proteins → ↑ amount of free drug in the plasma c. ↑ PaCO2 lowers intracellular pH → ↑ concentration of protonated local anesthetic within the cell d. ↑ PaCO2 lowers the Kd of local anesthetics

D. ↑ PaCO2 lowers the Kd of local anesthetics

What type of local anesthetics is most likely to precipitate an allergic reaction & why?

Ester local anesthetics due to the PABA metabolites -Chloroprocaine

T/F: The medial brachial cutaneous and intercostobrachialis nerves do not need to be blocked separately.

False

True or false: I'm performing a posterior lumbar Plexus block. We identify the spinous process and insert the needle just cephalad to the level of black.

False

True or false: The infraclavicular block produces a reduction in respiratory function.

False

T/F: For a rectus sheath block, the needle should be placed on the anterior side of the rectus abdominis just below the subcutaneous fat.

False Needle should be placed on the posterior aspect of the rectus abdominis along the rectus sheath

True or False. Paresthesia technique uses a small amount of electrical current to induce muscle contractions.

False, paresthesia technique needle contacting the nerve results in paresthesia to sensory area of distribution.

True or false: While performing the Labat approach for the sciatic nerve block the patient should be supine, with the knee elevated and hip flexed 90°.

False, patient should be in the lateral position with the knee and hip slightly flexed

True or False: Epinephrine should be used as part of their Bier Block.

False, should not be used

True or false: skin wheals are as successful as ultrasound when performing a saphenous nerve block.

False, they are 60% successful

Electrical nerve stimulation in regional anesthesia is a method of using a _________ intensity (up to ___ mA) and ______ duration (.05-1 ms) electrical stimulus (at ______ Hz repetition rate) to obtain a defined response (muscle twitch or sensation) to locate a ______ nerve or nerve plexus.

Electrical nerve stimulation in regional anesthesia is a method of using a low intensity (up to 5 mA) and short duration (.05-1 ms) electrical stimulus (at 1-2 Hz repetition rate) to obtain a defined response (muscle twitch or sensation) to locate a peripheral nerve or nerve plexus.

True or False. Using an Ultrasound can save time finding the nerve, but it takes longer for the block to set in if done properly because typically you can use less local anesthetic with US. Explain why you think you may be right.

False. Utilizing ultrasound with most blocks you are able to completely surround the nerve with visualization on the ultrasound screen. Being able to precisely deliver local anesthetic to the site not only decreases the amount needed, but will also decrease the time to onset. In comparison to the old artillery "fire for effect" method where you know you're close and dump all you got to hopefully get the nerve.

True or False: The Line of Grossi can only help with identifying placement of Infraclavicular block.

False: Although we discussed this as a starting point for the infraclavicular block US view, this can also be used for interscalene, supraclavicular, and axillary US placement.

True or False: The Interscalene Block is a great choice for surgeries involving the elbow.

False: Interscalene block would not provide RA to the elbow. Supraclavicular and/or infraclavicular blocks would be a better choice for this surgery.

Why has the term 3-1 block largely been abandoned in practice? a. What nerves does the technique typically anesthetize?

Femoral nerve block:Rarely does the block include the obturator nerve. a. The technique successfully blocks the femoral and the lateral femoral cutaneous.

What is a "compartment" block with fascia iliaca?

Femoral nerve, lateral femoral cutaneous, obturator & genitofemoral nerve course posterior to the fascia iliaca

3 primary nerves blocked with the proper administration of a posterior lumbar plexus block (psoas)

Femoral, lateral femoral cutaneous & obturator *Psoas is anterior to the transverse process*

What does the term 3-in-1 block refer to & why has the term largely been abaondined?

Femoral, lateral femoral cutaneous & obturator nerves may be blocked with a single injection below the inguinal ligament Not reliable as evidence of failures of most single injections to consistently block all 3 nerves (misses obturator)

Describe a paresthesia technique for adminsitering an axillary nerve block

Guided by surface landmarks, block needle place din proximity to target nerve/plexus. With contact with sensory nerve paresthesia is elicited in area of sensory distribution -Used for nerve localization

Why would it not be prudent to administer an interscalene block for a patient having surgery on the right shoulder who has a left-sided hemidiagphragmatic paralysis?

High risk for blocking ipsilateral phrenic nerve

In an interscalene brachial plexus block, proximal tracking of local anesthetic can lead to a blockade of sympathetic fibers innervating cervicothroacic ganglion. What may this lead to?

Horner's syndrome (PAM) -Ptosis: eye drooping -Anhydrosis: inability to sweat -Myosis: small pupil

In relation to the carotid artery, where does the internal jugular vein lie?

IJV lies *lateral to the carotid artery*

List the surface landmarks for the Psoas compartment block.

Iliac crest, vertebral spinous process (midline), PSIS

Utilizing the paresthesia technique, what do you do if the patient experiences intense, searing pain?

Immediately stop, the needle is intraneural and injection results in increased hydrostatic pressure and ischemia.

Paravertebral blocks usually require individual injections delivered at the various vertebral levels that correspond to the area of body wall to be anesthetized. Is this also valid when utilizing US guidance to reliably injected LA between the costotransverse ligament & posterior to the parietal pleura?

With ultrasound additional injections would not be required as the transverse process is able to be accurately identified Position of the needle is key to getting good spread Rib, 2cm lateral to spinous process, tuohy needle to find the transverse process, 1cm deeper, inject A Tuohy needle is a hollow hypodermic needle, very slightly curved at the end

Where do we find nerves within the base of the digits?

The four corners

Good anesthesia is obtained when LA is injected where?

In close proximity to the nerve/nerves to be blocked

Name two reasons why is a superficial cervical plexus block a better choice than deep cervical plexus block.

a. A superficial cervical plexus block has fewer risk factors (safer) than a deep cervical plexus block b. Probably just as effective and more reliable in the sense that it is technically a much easier block with less risk

Define the paravertebral space

In the placement of a paravertebral block: Transverse process, head of rib, costotransverse ligament, pleura identified Needle-in plane → costotransverse ligament ↓ displacement of the pleura

The lumbar plexus is formed by the ventral rami of L___ with occasional contribution from T__. It lies within the ___muscle with branches descending into the proximal thigh. The three major nerves from the lumbar plexus that make contributions to the lower limb & their movements

The lumbar plexus is formed by the ventral rami of L1-4 with occasional contribution from T-12. It lies within the psoas muscle with branches descending into the proximal thigh. The three major nerves from the lumbar plexus that make contributions to the lower limb are: obturator (L2-4)--adduction lateral femoral cutaneous (L1-3)--none-sensory only femoral (L2-4)--kick

Why is the interscalene brachial plexus block generally considered ulnar sparing?

The needle tip is typically more cephalad in the BP thus frequently sparing C-8 & T-1 nerve roots (areas innervated by the "ulnar nerve")

What is the transarterial technique?

The nondominant hand is used to palpate and immobilize the axillary artery, and a 22-guage needle is inserted high in the axilla until bright red blood is aspirated. The needle is then slightly advanced until blood aspiration ceases. Injection can be performed posteriorly, anteriorly, or in both locations in relation to the artery. A total of 30-40 mL LA is used.

What should you do if patients complain of TQ pain after 20-30 minutes?

Inflate the distal cuff first, then deflate the proximal cuff

What are more reliably positioned continuous nerve block catheters--axillary, supraclavicular or infraclavicular positioned catheters?

Infraclavicular positioned continuous nerve block catheters are more superior-less movement of the catheter -Axillary is superficial and prone to neuropathy

Peripheral nerve block that results in the highest blood level of LA in the blood

Intercostal-most vascular, shortest duration

All brachial plexus blocks miss which nerve 100% of the time, and what portion of the body does it innervate?

Intercostobrachial nerve a. Skin of the medial (give or take) upper arm, axilla and anterior chest. *listen to slide 85*

What is a caution with the interscalene block?

Ipsilateral (same side) phrenic nerve may be blocked is potentially blocked utilizing a nerve stimulator technique to administer an interscalene block

The superficial cervical plexus block supplies sensation to what areas?

Jaw, neck, occiput (posteriorly), areas of the chest and shoulder (near clavicle).

What is a field block? How many injections? Volume of LA? Examples?

LA in general location of cutaneous nerves - single or multiple injections - often large volumes of LA Examples: - superficial cervical plexus block - supplementation (e.g. axillary, ankle blocks) - surgeon injects local for minor procedures (e.g. ganglion cyst, breast bx)

What is its name, location and type of block performed at the elbow?

Lateral Cutaneous Nerve of the Forearm; 1-2 cm lateral to the biceps brachii tendon; field block

What does the musculotaneous nerve turn into in the forearm?

Lateral cutaneous nerve of the forearm

What is the proper positioning to perform psoas compartment block? Where is the puncture site?

Lateral recumbent or seated (cervical spine flexed backward) Puncture site: 3cm caudad & 4cm midline to spinous process L4. Sagittal insertion direction; upon contact with transverse process L5 retract & lower the needle & advance over the transverse process 2cm. Alternatively puncture is possible @ level of the L4 transverse process; advance caudad aligned needle under the transverse process

When performing a saphenous nerve block, the saphenous nerve can be found where in relation to the femoral artery?

Laterally

What 'line' is drawn between the interscalene muscles and the axillary region to provide quick reference for ultrasound placement of brachial plexus blocks, specifically the US placement for infraclavicular block?

Line of Grossi

What is a field block?

Local anesthetic injection targeting terminal cutaneous nerves @ the incision site

What are the roots for lumbar & sacral plexus? What do they share?

Lumbar: L1-4 Sacral: L4-S4 Share L4

You are trying to maintain a wide array of clinical skills and decide to do a deep cervical plexus block without ultrasound. What two landmarks are you looking for as a guide to your local anesthetic injection?

Mastoid process + C6 Tubercle (Chassaignac's tubercle)

Field block for 80kg patient. The anesthetic you have on hand is 0.25% bupivacaine. What is the max amount of bupivacaine may you use on your patient if you administer it with epinephrine? The label on your box says max dose you can administer with epinephrine is 3mg/kg.

Max dose with epi = 3mg/kg → 240mg 240 mg / 2.5mg/mL = 96mL of 0.25% bupivacaine

What three nerves can be accessed around the level of the elbow?

Median, Ulnar and Radial

When performing an ulnar nerve block, do you want to inject the local anesthetic at the level of the elbow or more proximal to the elbow? a. Why?

More proximal a. If local anesthetic is injected at the level of the elbow, it could be injected under the retinaculum and could cause nerve compression

If a patient complains of pain on the lateral aspect of the forearm which nerve was likely missed when an axillary block was administered?

Musculocutaneous--lateral antebrachial cutaneous

What would you expect to see on the US monitor when adminstiering a right-sided paravertebral block (transverse view) at T-4

Needle anterior to the costotransverse ligament Touhy needle used -External intercostal muscle -Internal intercostal membrane -Paravertebral space

For the psoas block what is the insertion technique?

Needle should be placed perpendicular to all planes (straight in) -Walk caudal off the transverse process

Where do the positive and negative leads go in using nerve stimulation?

Negative to needle Positive to ground

If we were able to create nerves of the same diameter with A being myelinated and B being unmyelinated which would be more sensitive to LA?

Nerve A because myelinated are more easily blocked--LA pool near axonal membrane

Relationship of the femoral nerve to the artery

Nerve is *lateral to the artery* N-A-V-E-L

In the administration of an intercostal nerve block where does the nerve lie in relation to the artery?

Nerve lies caudal to the artery V A N

What type of anesthesia technique uses a small amount of electrical current to induce *muscle contractions*

Nerve stimulation technique

What happens as the needle nears the nerve using nerve stimulation?

Nerve stimulator - delivers constant current (0.1 - 6 mA) *muscle contractions ↑ as needle nears nerve*

Is the intercostobrachial nerve typically blocked when performing an interscalene or axillary brachial plexus block?

No, it originates from T2 -It is not anesthetized with brachial plexus block because it is superficial and exits early

Should an infraclavicular block be performed on patients with an ipsilateral vascular catheter or ipsilateral pacemaker?

No. Avoid in these patients

Is it prudent to administer a regional anesthetic through an infected area?

No. Due to pH changes it will have decreased efficacy -Also potential to track infectious material to the nerve tissue?

When performing a posterior approach to a sciatic nerve block, what are the three landmarks you must identify?

PSIS, greater trochanter, sacral hiatus

What type of block would last considerably longer than intercostal nerve block? Why?

Paravertebral block would last longer because there are fewer blood vessels and will have a longer duration (24°) -Perineural cathether is also an option for paravertebral block

In a paravertebral nerve block the duration of sensory block is shorter or longer vs. intercostal nerve block?

Paravertebral nerve block is longer in duration-less vascular-vs. intercostal nerve block

Insertion of an infraclavicular perineural catheter should always be in the same location posterior to the axillary artery. What is concerning regarding this statement?

Patients' anatomy may differ-may not always be the best approach

How does one perform a sensory check with the psoas compartment block? Where should it be performed?

Pinch, pull hair, use alcohol wipe or poke with a sharpened tongue blade to test sensation. •Lateral aspect of thigh (Lateral femoral cutaneous) •Anterior aspect of thigh and medial aspect of lower leg (Femoral) •Medial aspect of thigh just above the knee (Obturator)

What are some possible complications of an interscalene block?

Possible answers: a. Ipsilateral phrenic nerve blockade → hemidiaphragmatic paresis, contraindicated with respiratory compromised patients or contralateral phrenic nerve injury b. Horner's syndrome → occurs from proximal tracking of local anesthetic and blockade of sympathetic fibers to the cervicothoracic ganglion → results in myosis, ptosis, anhidrosis c. Possible recurrent laryngeal nerve involvement → hoarseness d. Central neuraxial block with improper needle approach when not under ultrasound guidance a. Vascular injection → toxicity

What are the contraindications for a nerve block?

Possible answers: a. Patient uncooperative, pediatric, demented patients a. Coagulation disorders, or anticoagulation therapy b. Circumferential block of an extremity → ischemia c. Bloodstream infections d. LA toxicity limitations (sz & CV collapse) e. Pre-existing peripheral neuropathy f. Ipsilateral/contralateral nerve blockade concerns (interscalene & phrenic nerve)

What is the target for the psoas compartment block?

Posterior aspect of the psoas muscle is the target for lumbar plexus block

What nerve provides complete sensory innervation to the posterior thigh?

Posterior femoral cutaneous nerve (S1-3)

When administering an US guided supraclavicular block should the needle be inserted in-plane on the anterior-medial or posterior-lateral side of the probe? Why?

Posterior-lateral side of the probe -Lateral: needle advanced medial towards the subclavian artery -Brachial plexus found lateral and superficial to subclavian artery *This approach prevents going through the subclavian artery & phrenic nerve*

Should we, as prudent anesthesia providers, add epinephrine to our digital blocks?

Probably not a good idea from a legal standpoint, although the strength of the evidence against this practice is dubious

The Axillary block is excellent for what procedures?

Procedures distal to the elbow.

The posterior lumbar plexus (psoas compartment) block has one of the highest complication rates of any peripheral nerve block What additional risks would there be regarding the administration of a lumbar plexus block in comparison to an axillary block?

Proximity to sensitive structures Deep-requires a long needle Intrathecal & epidural injection Renal capsular injection Not easy to evacuate

Describe how to administer an intercostobrachial nerve block

Pt supine with arm abducted & externally rotated -Field block starting @ deltoid prominence inferiorly adminster 5mL LA extending to the most inferior aspect of the medial arm -ICB: nerve injury to tje medial nerve if too deep -Shallow to the medial nerve

The sacral plexus arises from where?

The sacral plexus arises from L4-5 & S1-4

The Sural nerve is made up of components of what two larger nerves?

The tibial and the common peroneal/fibular

The transverse abdominus plane block is a peripheral nerve block designed to anesthetize the nerves supplying the anterior abdominal wall from the ____ and ____.

The transverse abdominus plane block is a peripheral nerve block designed to anesthetize the nerves supplying the anterior abdominal wall from the T6 and L1.

Why has the transarterial technique fallen out of favor?

The trauma of purposefully penetrating the axillary artery twice along with a theoretically increased risk of inadvertent intravascular local anesthetic injection.

What does the "trident sign" look like?

The trident sign is found from the posterior lumbar plexus (psoas compartment) block view. It is the acoustic shadow from the L2-4 transverse processes when all 3 are in view.

In administering an axillary block you attempt to elicit a paresthesia to locate nerves (median) during insertion of the needle. Bright red blood is aspirated. What is the prudent thing to do?

This is expected in the transarterial technique -Slightly advance until blood aspiration ceases -Inject anterior/posterior in relation to the artery with 30-40mL anesthetic

Peripheral nerve block for surgeries on the shoulder & proximal humerous. What additional cutaneous branches need supplementation for "complete surgical anesthesia" of teh shoulder?

interscalene block -Need C3 & C4 (superficial cervical or local infiltration)

What type of needle is used for the paravertebral block?

Touhy needle

Where do the roots exit?

Transverse process

When using ultrasound for a posterior lumbar plexus (Psoas Compartment) block, what is the ultrasound image caused by the acoustic shadows of the transverse process called?

Trident sign or picket fence

T/F: The musculocutaneous nerve usually needs to be blocked separately during an axillary nerve block.

True

True or False: The Brachial Plexus is relatively continuous with the Cervical Plexus.

True

True/False: The popliteal-sciatic block can be done in the supine, prone, or lateral position.

True

True or False: The recurrent laryngeal nerve lies anterior to the subclavian artery.

True But it's not near and not likely to be blocked

T/F: An advantage of a TAPS Block over a Rectus Abdominis block is the TAPS block is of longer duration

True, TAPS block is of longer duration vs. RA RA advantage is it is more localized

True or False. You can dilute your local anesthetic in order to preferably get a sensory blockade while preserving some motor.

True. You can dilute your local anesthetic in order to preferably get a sensory blockade while preserving some motor. -alpha motor neurons require more anesthetic to block

True or False: The supraclavicular block is less effective for shoulder surgery when compared to the Interscalene block

True: The Interscalene provides more coverage for the shoulder when compared to the Supraclavicular block.

When does the surgeon perform "field blocks"?

Under deep sedation/GA

What is the maximum number of catheters that can be used for continuous peripheral nerve blocks? a. What is the maximum rate of infusion that can be administered at once?

Usually no more than 2, but on rare occasions 3 can be used a. Usually not greater than 20 ml/hr in total, but this can be based on patient condition and judgement of the provider

In the axillary nerve block what is the relationship between the brachial plexus & axillary artery? IN relation to vein?

Vein is medial to the artery in the axillary nerve block Brachial plexus lies around the artery M-U-R + MC

Where does the vertebral artery enter the vertebral foramen? What path does it travel?

Vertebral artery enters vertebral foramen at C-6 and travels cephalad just posterior to transverse process and medial to lateral border of transverse process

When performing an interscalene brachial plexus block utilizing either paresthesia or nerve stimulator technique, what angle should the needle be inserted & why?

~45° avoiding major vessels including vertebral artery between the vertebrae

Cords/branches relationship

• Cords (lateral, medial, posterior) - Lateral - musculocutaneous and median • Medial - ulnar and median • Posterior - axillary and radial

Boundaries for the lumbar plexus

• Lumbar Plexus: posterior to psoas major muscle & anterior to quadratus lumborum muscle and transverse process of L5 vertebra -Medial boundary is the components of vertebrae (e.g. L4-5 vertebrae)

Brachial plexus:

• Roots: C5-T1 (Ventral rami) - C4 &/or T2 minor/absent • Trunks (superior, middle, inferior) • Divisions (anterior, posterior) • Cords (lateral, medial, posterior) - Lateral - musculocutaneous + median - Medial - ulnar + median - Posterior - axillary + radial • Branches (radial, ulnar, median, musculocutaneous, axillary)

What are the techniques for the axillary block?

• Trans-arterial • Paresthesia • Peripheral Nerve Stimulator 1. Single 2. Multiple • Perivascular technique • Ultrasound

Commonly used LA

• lidocaine 1 - 2% • mepivacaine 1 - 2% • bupivacaine 0.25 - 0.75% • ropivacaine 0.2 - 1.0% • chloroprocaine 2-3% Solutions may be diluted down striving to get sensory while preserving some motor

What is the Raj test?

•1-2 ml test dose of LA → twitch rapidly fades (Raj test)

How is motor checked for lumbar plexus (psoas) block?

•Flex leg at hip and have patient raise lower leg (Femoral nerve innervation to the quadriceps) •Abduct leg, have patient pull in (adduct) against pressure (Obturator)

Following the administration of an axillary bock, you utilize the 4 Ps to evaluate the quality and completeness of the block. What do they stand for and what are the corresponding nerves?

Push: radial extend forearm (triceps) Pull: flex forearm-musculocutaneous Pinch: little finger-ulnar (lateral) Pinch: palmar surface index finger-median Used to assess any brachial plexus block

Describe the bier block technique

Put cuff on Exanguinate with tight wrap Pump up distal cuff, then prox Deflate distal cuff

What nerve branches do the 4-P's assess for?

Radial, Ulnar, Musculocutaneous, and Median N.

Where is a rescue block performed for failed axillary block? Where exactly?

Rescue Blocks for failed axillary blocks are often performed in *the elbow region* -Prox/distal to avoid compression if LA injected in the retinaculum @ the elbow

Draw & label the brachial plexus

Roots: C5-T1 Trunks: Superior, middle, inferior Divisions: 3 anterior, 3 posterior Cords: lateral, posterior, medial Terminal branches: -Musculocutaneous -Axillary -Radial -Median -Ulnar

What is the difference between paresthesia and nerve stimulation techniques?

Sensory vs. motor stimulation Paresthesia Technique: Needle contacts nerve, results in paresthesia to *sensory area of distribution Nerve Stimulation Technique: Small amount of electrical current to induce *muscle contractions*

When is a Bier block best utilized?

Short surgical procedures on hand, forearm and foot 1. Carpal Tunnel Release 2. Trigger finger release 3. Dorsal ganglion cystectomy 4. LE or foot usually diagnostic block for RSD

An interscalene block is an acceptable peripheral nerve block for what surgeries?

Shoulder, proximal humerus, and clavicle (when combined with a cervical plexus block)

S/sx of LA toxicity: CV & neuro with increasing degree of intoxication

Smaller inhibitory neurons blocked first CV: hypertension, tachycardia → bradycardia, hypotension → aystole Neuro: mentally "abnormal → metallic taste, tinnitus, dizziness, confusion → seizure

What are the risks associated with an infraclavicular block done with either a peripheral nerve stimulator or ultrasound guidance?

Some risks associated with infraclavicular blocks are hemothorax, pneumothorax, chylothorax (on the left side), intravenous or intra-arterial injection

Administering a superficial cervical plexus block is essentially just injecting LA in a subcutaneous plane along the posterior border of what muscle?

Sternocleidomastoid muscle

Describe the approach & needle angle for the superficial cervical plexus block. Surgery use.

Straight line between the mastoid process & C6 transverse process Insertion site mid posterior border SCM (draw line between mastoid process & C6 transverse process) -SubQ fan (wheal) cephalad & caudad -Limited entry sites -Angle the needle downward to avoid the vertebral artery SubQ under jaw line (fascial nerve decreases pain from retractors)

Where does the subclavian artery join the brachial plexus? Where does it lie in relation to the BP?

Subclavian artery - Joins BP at level of 1st rib, lies inferior and anterior to BP

Do supra or infraclavicular continuous peripheral nerve blocks provide superior analgesia?

Supraclavicular CPNBs provide superior analgesia

PNB once described as spinal of the arm? Why might there be weakness in this description?

Supraclavicular block -Misses the intocostobrachialis

Which approach for a brachial plexus block would provide the most practical, reliable and complete anesthesia for surgery on the elbow?

Supraclavicular provides anesthesia @ or distal to the elbow

Does the sural nerve innervate the lateral or medial side of the foot?

Sural innervates the lateral foot Saphenous innervates the inner foot

What is the superficial cervical block used for?

Surgeries: unilateral procedures on the neck (CEA) + adjunct to interscalene block (shoulder surgery)

What are some common surgical implications to provide an Ilioinguinal/Iliohypogastric nerve block?

Surgical procedures involving the lower abdomen or inguinal region, e.g. inguinal herniorrhaphy, C-Section, abdominal hysterectomy, etc.

What is the greatest immediate risk of PNB? How do you help rpevent this?

Systemic toxicity greatest immediate risk Use 2-3 mL test dose (with epi 2.5 - 5 mcg/mL) - 5 mL incremental dosing (aspirate in between each dose) - "immobile needle" technique

From which root does the intercostobrachial nerve originate, and what classification of block is utilized?

T2; Field Block

What level of blockade is achieved with the Obturator Block?

Terminal branches of lumbar plexus (L2-L4) distal to inguinal ligament.

1:200,000 = x mcg/mL How is this concentration used to determine how much epi to put in xmL LA?

1:200,000 = 5 mcg/mL (using 1:1000 vial of epi) Multiply this concentration x mL for LA solution

What is the % concentration of a solution containing 20mg/mL?

2%

How many peripheral nerve blocks can you use one one nerve? What is the max mL?

2, possibly 3 Total mL 20 (combined total)

In proper administration of the paravertebral block, how many centimeters should you move lateral to the spinous process?

2.5 cm

Why is an interscalene approach to the brachial plexus traditionally not considered the best choice for a patient having surgery on their ring finger & 5th digit?

"Ulnar sparing" Ulnar nerve from C8-T1 may be spared since interscalene brachial plexus blocks C5-C7

Name at least 6 potential benefits of regional anesthesia

- Analgesia - ↓ stress response - ↓ opioid-related SE - ↓ systemic analgesia requirements - ↓ general anesthesia requirements - ↓ development of chronic pain - ↑ patient satisfaction - ↓ sleep disturbances - ability to assess neuro status - ↓ pulmonary complications (atelectasis)

Peripheral nerve blocks for complete below the knee anesthesia

- Sciatic nerve block (popliteal) - Saphenous nerve block (sensory only)

Patient populations more likely to benefit from regional anesthesia

-*Multiple comorbidities* -OSA -High risk PONV -Chronic pain -Hx MH

Describe appropriate PNS settings for needle nerve location -mA--initial vs. LA admin -ms--motor vs. epidural -Hz

-1.5-2mA when initial advancing the needle then work down to 0.2-0.5mA when determining LA administration -0.1 ms for motor peripheral nerve -0.2 ms for epidural space/intrathecal, 1 mg epidural -0.5-4 Hz (0.2 normal)

Appropriate PNS settings for percutaneous nerve stimulation -mA -ms -Hz Colors to what electrodes?

-3-5 mA (current) -1.0 ms (duration) -1 or 2 Hz (frequency) *Negative to needle, red to patch*

What are the anatomical landmarks (needle insertion site) in performing a single shot interscalene block

-Across from the cricoid cartilage (aligns with transverse process of the 6th cervical vertebrae) -Between anterior & middle scalene muscles which lie at the level of the roots/trunks of the brachial plexus

What form the cervical plexus?

-Anterior rami C1-C4 -Plastysma muscle to the poserior sternocleidomastoid (superficial block sensory fibers only)

What could you mix with the LA to increase the length/efficacy?

-Epi -Dexamethasone -Dexmedetomidine -Clonidine -Other LA

What are the principle landmarks for performing a sciatic nerve block when using the posterior classic or labat approach?

-Greater trochanter to the PSIS, midpoint, perpendicular line caudually -Greater trochanter to the sacral hiatus Intersection marked--initial needle point -10cm needle inserted @ angle perpendicular to the planes to the skin until plantar/dorsiflection

Describe the approach & landmarks regarding performing the fascia iliaca technique when US not implemented -Elements identified -Needle insertion angle -injection mL -Nerves targeted

-ID inguinal ligament & femoral artery pulse-femoral crease below -Divide inguinal ligament in thirds -2cm distal to junction of middle & outer thirds -Insert short, blunt-tipped needle in slightly cephalad direction -2 pops felt--to layers of the fascia (lata & iliaca) -Aspirate once through the fascia iliaca -Inject 30-40 mL LA -Anesthetizes femoral & lateral femoral cutaneous nerves

What LA have the quickest onset? Duration shortest-longest

-Onset-fastest is chloroprocaine in the concentrations we give -Duration (short-long): chloroprocaine, mepivacaine, lidocaine, ropivacaine, bupivacaine (longest)

Factors to consider when making decisions regarding choices of LA to use for PNB

-Onset-fastest is chloroprocaine in the concentrations we give -Duration (short-long): chloroprocaine, mepivacaine, lidocaine, ropivacaine, bupivacaine (longest) -Relative blockade of sensory & motor fibers (dilute to have sensory > motor with non-selective) -Potential toxicity-neuro/cardiac -Site-specific risks

What are the three different techniques for peripheral nerve blocks?

-Paresthesia technique -Nerve stimulation -Ultrasound guidance

Specific peripheral nerve block locations that are most concerning in regards to bleeding disorders and pharmacological anticoagulation

-Posterior lumbar plexus-near retroperitoneal space-deep -Paravertebral-near neuraxis & cannot apply pressure Cannot directly apply pressure for bleeding

Explain advantages of using US guidance to perform saphenous nerve blocks proximal to the knee (adductor canal) versus placing a subcutaneous wheel distal to the knee

-Reliability-US proximal to the knee blocks the saphenous nerve 100% -Wheel distal to the knee is superficial with 60% chance of blocking the saphenous nerve -Duration -Efficiency

Type of medications to have readily available when administering regional anesthetics

-Resuscitative rx -O2 via NC/SM: ↓ hypoxia, ↑seizure threshold -Intralipids (bupivacaine has cardiac toxicity) -Conscious sedation-ketamine, bz, opioids o Benzodiazepine: ↓ anxiety + ↑ seizure threshold if breathing -Propofol-tx seizures -NMB to relax the airway in an emergency

Appropriate blocks per site-specific procedures -Shoulder -Arm -Elbow -Forearm -Hand

-Shoulder: interscalene (higher volume to get C3-4) -Arm: supra (or interscalene if all roots blocked) -Elbow: supra/infra -Forearm: infra/axillary -Hand: axillary

What is the difference in insulated/non needles?

-Stim: insulated needle (only tip stimulates) -non-insulated (stimulation along the entire needle)

5 risks associated with continuous peripheral nerve blocks

-Systemic LA toxicity -Catheter retention -Nerve injury -Infection-sterile technique used -retroperitoneal hematoma-lumbar plexus -Falling risk (femoral)

Surgical procedure considerations to discuss with the surgeon related to peripheral nerve blocks

-Tourniquet placement -Bone grafting -Surgical duration -Anticipated course of recovery -Level/duration of post-op pain (single injection vs. continuous infusion options)

Ppropriate uses for interscalene vs. axillary surgeries

-interscalene for shoulder and proximal humerus surgical procedure -axillary for surgeries distal to the mid-humerus

In the paresthesia technique what would indicate you are perinerual vs. intraneural?

-perineural → brief accentuation of paresthesia -intraneural → hydrostatic pressure (ischemia) (intense, searing pain... immediately stop)

Given 1mL epinephrine 1:1000 and 20mL 3% Nesacaine what volume of epinephrine must be added to the LA in order to obtain 1:400,000 concentration of epinephrine in 20mL of 3% Nesacaine?

0.05mL = 50mcg 1:400,000 = 2.5mcg/mL

Given 1mL epinephrine 1:1000 and 30mL 0.5% ropivacaine what volume of epinephrine must be added to the LA in order to obtain 1:500,000 concentration of epinephrine in 30mL of 0.5% ropivacaine?

0.06mL = 60mcg 1:500,000 = 2mcg/mL

Given 1mL epinephrine 1:1000 and 30mL 2% lidocaine what volume of epinephrine must be added to the LA in order to obtain 1:200,000 concentration of epinephrine in 30mL of 2% lidocaine?

0.15mL = 150mcg 1:200,000 = 5mcg/mL

While using PNS for regional anesthesia, the occurrence of a motor response at what mA setting should prompt caution? What does this indicate?

0.2-0.5 mA; a motor response at 0.5mA indicates needle-nerve contact or intraneural needle placement.

Describe appropriate PNS settings for interscalene block utilizng a combined US, peripheral nerve stimulator technique? -mA -ms -Hz

0.2-0.5mA 0.1/0.2 ms 1-2 Hz

What LA do you use for a bier block? -Upper extremity -Lower extermity

0.5% lidocaine • 40 - 50ml for upper extremity • up to 100ml for lower extremity (0.25%) NO EPINEPHRINE NO PRESERVATIVES

LA of choice for Bier block -mL for upper extremity -How quickly should LA be injected?

0.5% lidocaine, no epi, no preservatives Arm: 40-50mL Inject slowly over 2 minutes--if pushed too fast increased seizure risk by getting LA systemic from increased pressure overcoming tourniquet pressure 0.25% thigh, greater volume

Bier block technique

1. Apply web roll (flat, thin cotton) and double tourniquet to arm (avoid wrinkles) 2. Start small gauge IV (22-25ga) on dorsum of hand 3. Elevate extremity above heart level and exsanguinate with Esmarch by wrapping proximally (Complete exsanguination is key to a successful block) 4. Inflate the distal first cuff, then proximal cuff, and then deflate the distal cuff. (allows the local anesthetic to travel to this area and provide anesthesia further into the procedure) 5. Unwrap Esmarch cautiously to avoid dislodging the IV 6. Inject local anesthetic slowly (over 2 minutes) to prevent overcoming the tourniquet occlusion pressure

Name three nerves that branch from the brachial plexus just proximal to where an axillary block is typically administered.

1. Axillary 2. Musculocutaneous 3. Medial brachial cutaneous

What are some potential problems with a psoas compartment block?

1. Intravascular Injection 2. Pain from lumbar paravertebral muscle spasm can occur postoperatively

What are the 2 questions you utilize with the paresthesia technique?

1. Is the needle contacting the nerve or in it? 2. Is the injection perineural or intraneural?

4 theoretical mechanisms for developing nerve injuries associated with peripheral nerve blocks

1. Local ischemia from increased injection pressure 2. local ischemia from vasoconstrictors (epi)-es[ ears, fingers, nose, toes 3. Neurotoxic effect of LA 4. Direct trauma to nerve tissue

What are 2 reasons bupivacaine is not recommended for the administration of IV regional anesthesia (bier blocks)?

1. Longer duration-tourniquet pain is the limiting factor -Duration 45-60 minutes 2. Increased toxicity risk

2 disadvantages for paresthesia technique for the administration of supraclavicular block

1. Nerve damage (chronic parasthesias) 2. LA Toxicity 3. Arterial puncture 4. Respiratory complications (ipsilateral phrenic nerve palsy) -High risk for pneumothroax -Recurrent nerve palsy

When assessing for brachial plexus block effectiveness using the 4-P's, what do the 4-P's stand for?

1. Push - Extend forearm = Radial 2. Pull - Flex forearm = Musculocutaneous 3. Pinch - Little finger = Ulnar 4. Pinch - Palmar surface index finger = Median

3 areas where field blocks are commonly administered by anesthesia

1. Superficial cervical plexus-neck/shoulder 2. Intercostal brachial nerve-medial upper extremity proximal to the elbow 3. Saphenous nerve-medial leg/ankle joint

How high should the TQ pressure be in a bier block?

100mmHg higher than patient's systolci pressure

If the arm is abducted more than ____ you may get decreased arterial pulsation.

90 degrees

Which local anesthetic is associated with methemoglobinemia? a. Benzocaine b. Bupivacaine c. Mepivacaine d. Ropivacaine

A. Benzocaine

Where is the target for the posterior lumbar plexus (psoas compartment) block? a. In between the transverse processes of the lumbar vertebra b. Inside the vertebral body c. Anterior to the spinal cord d. In between the transverse processes of the thoracic vertebra

A. In between the transverse processes of the lumbar vertebra

What sensation or function would be most likely felt by the patient first when recovering from a regional peripheral nerve block? a. Motor b. Autonomic c. Pain d. Temperature

A. Motor

Who is the least appropriate patient for the anterior sciatic nerve block? a. Obese patient b. Underweight patient c. Patient who is unable to turn on his side d. All are equally appropriate patients for this block

A. Obese patient

In the classic sciatic nerve block, what are the 3 main bony landmarks used to find the sciatic nerve? a. PSIS, Greater Trochanter, Sacral Hiatus b. ASIS, Greater Trochanter, Ischial Tuberosity c. C) PSIS, Ischial Tuberosity, Medial Malleolus d. D) Greater Trochanter, PSIS, Olecranon process

A. PSIS, Greater Trochanter, Sacral Hiatus

Which of the following approaches is best for an axillary block? a. Paravertebral approach b. Intercostal approach c. Lateral oblique approach d. Anterolateral approach

A. Paravertebral approach

Fascia Illiaca blocks are commonly used to provide analgesia for: a. Total knee Replacements, femur fractures b. Hip fractures, total hip replacements and hip arthroscopy c. Below the knee amputations, ankle surgeries d. Inguinal hernia

B. Hip fractures, total hip replacements and hip arthroscopy

In the classic sciatic nerve block, what position should you place the patient in? a. A) prone position b. B) Lateral position with knee flexed c. C) supine position with knee flexed d. D) reverse Trendelenburg position, legs in figure four position

B. Lateral position with knee flexed

What are the target nerves for the psoas compartment block? a. Brachial plexus b. Lumbar plexus c. Sciatic nerve d. Sacral plexus

B. Lumbar plexus

When performing an axillary block, which of the following techniques is most effective? a. Single injection technique b. Multiple injection technique c. Posterolateral approach using an insulated needle d. None of the above

B. Multiple injection technique because of the fascial separation between the nerves.

What would be the best choice of anesthetic for CEA surgery? a. Deep superficial cervical plexus block b. Superficial cervical plexus block c. Combination of A and B d. Interscalene block

B. Superficial cervical plexus block

Which of the following blocks results in the highest blood levels of a local anesthetic per volume injected of any block in the body? a. Interscalene b. Axillary c. Intercostal d. Femoral

C. Intercostal

All of the following are true regarding the lateral femoral cutaneous nerve bock EXCEPT: a. Lateral Femoral Cutaneous Nerve is lateral to the Femoral Nerve. b. Lateral Femoral Cutaneous Nerve is lateral to the Sartorius Muscle. c. Lateral Femoral Cutaneous Nerve is anterior/superficial to the Fascia Lata. d. Lateral Femoral Cutaneous Nerve field block can be performed with 10-15mls of local anesthesia.

C. Lateral Femoral Cutaneous Nerve is anterior/superficial to the Fascia Lata.

While evaluating a lower extremity block you notice that the medial aspect just above the knee does not have any sensation to sensory stimulation (touch or alcohol wipe). Which nerve has been blocked? a. LFC b. Femoral c. Obturator d. Radial

C. Obturator

At what level of the brachial plexus is an infraclavicular block? a. Distal branches b. Roots and trunks c. Divisions d. Cords

D. Cords

When conducting a Fascia Iliaca block with landmarks, what should be your approach? a. Palpate the femoral artery and insert needle 2 fingers-breadths lateral of femoral artery. b. Palpate femoral artery and insert needle at 90-degree angle trans-arterial and aspirate for blood, when blood ceases deposit local anesthetic. c. Palpate the greater trochanter and insert needle 5cm medial d. Divide inguinal ligament into 3rds, insert needle 2cm distal to the junction of the middle and outer 3rd segment

D. Divide inguinal ligament into 3rds, insert needle 2cm distal to the junction of the middle and outer 3rd segment

All of the following are true of a Bier Block except: a. Inject local anesthetic over 2 minutes b. Only Lidocaine 0.5% is approved c. Place a double bladder tourniquet, inflating the distal cuff and then the proximal cuff d. It is safe to deflate the tourniquet cuff earlier than 20 minutes following LA injection

D. It is safe to deflate the tourniquet cuff earlier than 20 minutes following LA injection

What field block can successfully block the lateral femoral cutaneous nerve, the obturator nerve, and the femoral nerve with a single injection?

D. Psoas compartment block

Regarding SUPRA-clavicular approach to brachial plexus nerve block the following are true except: a. A 5cm 22-gauge short-bevel, insulated stimulating needle is inserted in plane toward brachial plexus and a lateral to medial direction b. The skin of the proximal part of the medial side of the arm is not anesthetized by this block c. When attempting to deposit local anesthetic high resistance may indicate interfascicular injection and should not be done d. There is no risk of phrenic nerve block since supraclavicular block is performed caudal to the nerve e. When injecting LA start at the deepest and furthest structures and then redirect the needle and inject LA more superficial

D. There is no risk of phrenic nerve block since supraclavicular block is performed caudal to the nerve

The earliest signs of systemic toxicity are usually caused by blockade of _______ pathways in the _________.

The earliest signs of systemic toxicity are usually caused by blockade of *inhibitory* pathways in the *cerebral cortex*. -Inhibitory neurons are smaller & blocked first

A 58-year-old woman with a recent diagnosis of end stage renal disease is scheduled for creation of an upper extremity fistula just proximal to the elbow. Her medical history includes insulin-dependent diabetes, hypertension, and an 80 pack-year history of smoking. Which of the following is TRUE? a. An axillary block would be the best option since it has least likelihood of complications, including pneumothorax. b. An interscalene block would be best to cover all sensory nerves to the upper arm, including the intercostobrachial nerve. c. A supraclavicular block is performed at the level of the cords and can effectively block the brachial plexus for the upper arm. d. An infraclavicular block is performed at the distal trunks and can be used to provide adequate sensory block for the surgery. e. The surgery can be performed with sedation and local infiltration of anesthesia provided by the surgeon.

E. The surgery can be performed with sedation and local infiltration of anesthesia provided by the surgeon.