Positioning
Scapular winging is usually the result of injury to the
Long thoracic nerve which arises from C5-C7 Scapular winging is the dorsal protrusion of the scapula
Which nerve innervates the muscles that produce pronation and flexion of the wrist and flexion of the thumb, middle, and index fingers? A. median B. ulnar C. spinal accessory D. radial
A
Following a prolonged case with the hips in severe flexion, a patient exhibits noticeable bilateral foot drop in PACU. What nerves do you suspect are injured? A. Sciatic B. Lateral femoral cutaneous C. Genitofemoral D. Femoral
A If a patient is positioned with the hips markedly flexed, it can produce stretch of the sciatic nerve. If the buttocks are not padded well enough in the seated position, the sciatic nerve can be compressed where it exits the pelvis. Like injury to the common peroneal nerve, injury to the sciatic nerve can manifest as foot drop.
Which position would produce the least amount of decrease in the functional residual capacity? A. Sitting B. Prone C. Supine D. Trendelenburg
A In the sitting position, the abdominal contents shift caudally, allowing for easier ventilation. Lung volumes and the FRC are typically within normal limits. If the legs and hips are flexed against the abdomen, however, they can push the abdominal contents against the diaphragm and result in a decreased FRC. in the prone positing the lung capacity and perfusion actually increase
Which position exhibits the least amount of cardiovascular change in the anesthetized patient? A. Supine B. Prone C. Lateral jackknife D. Sitting
A In the supine and standard lateral positions, the cardiac changes are usually minor. In the sitting, prone, lateral jackknife, and kidney rest positions, however, the lower extremities are dependent. This can produce a decrease in cardiac output and blood pressure due to decreased venous return.
Damage to the long thoracic nerve can result in winging of the scapula by causing dysfunction of the _____ muscle. A. serratus anterior B. trapezius C. latissimus dorsi D. rhomboid minor
A Innervation to the serratus anterior muscle is supplied by the long thoracic nerve. The long thoracic nerve is comprised of fibers from C5, C6, C7, and occasionally, the C8 nerve roots. Damage to the long thoracic nerve can result in dysfunction of the serratus anterior muscle and dorsal protrusion of the scapula, also known as winging of the scapula.
Which position would most likely be selected for a procedure that requires access to both the abdomen and the perineum? A. low lithotomy B. standard lithotomy C. high lithotomy D. prone
A Low Lithotomy position is similar to standard lithotomy position except that the thighs are only flexed about 30-45 degrees rather than 90 degrees. It is often used for procedures that require access to both the abdomen and the perineum. It also results in less alteration in lower extremity perfusion pressures compared to standard or high lithotomy position.
With what surgical position is rhabdomyolysis associated? A. Lateral decubitus B. Prone C. Supine D. Lithotomy
A Rhabdomyolysis is associated with the lateral decubitus position. Factors that are considered to contribute to this phenomenon include prolonged surgical time, hypotension, and the pressure of the operating room table against the gluteal and flank muscles.
The AANA code of ethics mandates that a nurse anesthetist accept the responsibility conferred by the A. state, profession, and society B. profession, employer, and supervising physician C. state, profession, and employer D. society, profession, and employer
A The AANA code of ethics mandates that nurse anesthetists accept the responsibilities conferred upon them by the state, the profession, and society.
what happens to these listed structure when the pt is in a head up position Abd viscera Diaphragm lungs pulmonary compliance peak inspiratory pressure Total lung volume FRC
Abd viscera - Caudad Diaphragm = impaired function lungs= expanded freely pulmonary compliance = increased peak inspiratory pressure= decreased Total lung volume= increased FRC= increased
what happens to these listed structure when the pt is in a head down and supine position Abd viscera Diaphragm lungs pulmonary compliance peak inspiratory pressure Total lung volume FRC
Abd viscera = cephalad Diaphragm = impaired function lungs = compressed pulmonary compliance = decreased peak inspiratory pressure= increased Total lung volume= decreased FRC= decreased
A significant risk for perineal crush injury is associated with which of the following situations? A. In lithotomy position for hysteroscopy B. On traction table to reduce a femur fracture C. On Wilson frame for lumbar microdiscectomy D. In lateral decubitus position for shoulder arthroscopy
B A traction table places the patient supine with one leg elevated and the affected leg placed in traction. A perineal post is positioned between the patient's legs to keep them stationary while the traction pulls on the leg. The elevated leg suffers the risk of hypoperfusion while the perineal post poses a risk of crushing the perineum.
Which of the following is true in a spontaneously breathing, anesthetized patient placed in the lateral decubitus position? A. Functional residual capacity remains unchanged B. The nondependent lung becomes more compliant C. The dependent lung becomes more compliant D. Ventilation is preferentially distributed to the dependent lung
B In the spontaneously breathing, anesthetized patient in the lateral decubitus position, the functional residual capacity decreases almost immediately. The nondependent lung shifts to a position of greater compliance. The dependent lung loses FRC and becomes less compliant. As a result, ventilation is preferentially distributed to the nondependent lung.
Midcervical tetralgia is associated with paralysis below the level of A. C1 B. C5 C. T1 D. T12
B Midcervical tetralgia is a catastrophic injury that occurs following hyperflexion of the neck. It occurs due to stretching of the spinal cord with resulting ischemia of the cord in the midcervical area. The result is paralysis below the level of C5. Midcervical tetralgia is typically associated with excessive head flexion in the sitting position, but it has also occurred after prolonged flexion of the head in the supine position.
Which of the following effects would you expect to see in a patient changing from the erect position to supine? (select two) A. Increase in heart rate B. Decrease in peripheral vascular resistance C. Increase in cardiac output D. Increase in mean arterial pressure
B C When moving from the erect to supine position, there is a considerable increase in central blood volume. The resulting stretch of baroreceptors in the central circulation results in a decrease in MAP, heart rate, and peripheral vascular resistance, whereas cardiac output and stroke volume increase.
Which of the following is true regarding anesthesia-related ulnar neuropathy? (select two) A. It is more common in patients with a low to normal body mass index (BMI) B. It may develop despite conventional positioning and padding C. It is more common in women than men D. Elbow flexion is a common cause of ulnar neuropathy
B D Ulnar neuropathy occurs more often in patients with a high BMI and occurs more commonly in men than in women. It is believed to be more common in men because the tubercle of the coronoid process is 1.5 times larger in males, the cubital retinaculum tends to be thicker, and there is less adipose tissue over the medial aspect of the elbow.
You are conducting a preoperative assessment on a patient and find that they are hypotensive, bradycardic, and have a slow respiratory rate. These are signs and symptoms of acute abuse of which substance? A. LSD B. Cocaine C. Opioids D. Amphetamines
C Respiratory depression, hypotension, and bradycardia are all signs and symptoms of acute opioid abuse. A patient with acute abuse of LSD, cocaine, or amphetamines will exhibit tachycardia and hypertension.
Your patient is emerging from a craniotomy in the sitting position. Which postoperative symptom would most likely be attributed to hyperflexing the patient's neck towards the chest? A. postoperative blindness B. trigeminal neuralgia C. severe swelling of the tongue D. postural hypotension
C The standard sitting position for neurosurgery involves placing the patient in a semi-reclining position with the legs elevated to about the level of the heart, and the head and neck are flexed slightly forward. If the head is flexed forward, it is important to ensure it is not hyperflexed with the chin on the chest. This could result in midcervical tetraplegia. Severe flexion of the neck can also produce obstruction of venous and lymphatic drainage and severe swelling of the tongue.
Which of the following positioning techniques indicates the anesthetist's understanding of appropriate methods of protecting the ulnar nerve from position-related injury? A. Both arms are abducted less than 90 degrees B. Both hands are positioned prone C. Both hands are positioned supine D. Both arms are tucked at the sides
C The ulnar nerve is most at risk for compression damage where it passes under the medial epicondyle. Pronation of the hand positions the ulnar nerve directly against the table surface, making it a high-risk position. Supinating the hand shifts the ulnar nerve above the table surface and allows the olecranon to bear the weight of the arm. Tucking the arms at the sides can still leave the ulnar nerves at risk and padding should be placed around the elbows to protect the ulnar nerve. Abducting the arms less than 90 degrees provides a degree of protection for stretch injury to the brachial plexus, but has little bearing on the ulnar nerve.
Which of the following parameters will increase when an anesthetized patient is placed in the seated position? A. Cardiac index B. Pulmonary artery wedge pressure C. Systemic vascular resistance D. Central venous pressure
C When placed in the seated position, the cardiac index, pulmonary artery wedge pressure, and central venous pressure decrease substantially, but the systemic vascular resistance increases.
A patient undergoing hysteroscopy is placed in lithotomy position with medially-placed strap supports. In the recovery area, the patient complains of numbness and tingling along the medial aspect of the calves. You suspect there could be damage to the A. sciatic nerve B. obturator nerve C. common peroneal nerve D. saphenous nerve
D Although lithotomy position can result in damage to any of these nerves, this patient's presentation is most consistent with damage to the saphenous nerve, which innervates the medial calf. This is most likely to occur with medially placed strap supports. Extreme flexion at the thigh can result in injury to the sciatic, obturator, and femoral nerves while injury to the common peroneal nerve can occur if the lateral thigh is allowed to rest on strap supports.
Which of the following is a known risk factor for the development of postoperative visual loss following spine surgery? A. Female gender B. Sarcoidosis C. Intraoperative hypertension D. Obesity
D Patients undergoing general anesthesia and prone positioning for spinal surgery have a risk of postoperative visual loss due to occlusion of the retinal arteries producing ischemic optic neuropathy. The primary cause is pressure around the periorbital area which increases intraocular pressure and reduces blood flow through the retinal artery. The risk is higher in obese patients. Other risk factors include male gender, blood loss greater than 1 liter, surgery that is longer than 5 hours, and hypotension.
When placed in the Trendelenburg position, the normal response to the associated increase in venous return is _____ and a(n) _____ in the heart rate. A. vasoconstriction, increase B. vasoconstriction, decrease C. vasodilation, increase D. vasodilation, decrease
D The normal response to the increased venous return in the Trendelenburg position is vasodilation and a decrease in the heart rate due to baroreceptor reflex stimulation. Patients who are hypotensive, however, may exhibit a variable response to the Trendelenburg position.
Which of the following factors is common in all peripheral nerve injuries due to positioning? A. Compression B. Transection C. Stretch D. Ischemia
D The primary mechanisms responsible for peripheral nerve injury are transection, compression, stretch, and kinking, but the component that stems from these mechanisms and is common to all peripheral nerve injuries is ischemia.
with DM what nerve should you be careful in positioning
Femoral due to femoral neuropathy
In the supine position, which of these positions is responsible for median nerve injury Forearm pronation on the arm board Forearm supination on the arm board Hypertension of the elbow Extreme flexion of the elbow
Hyperextension of the elbow Extreme flexion of the elbow - stretches the ulnar nerve
during posterior spinal fusion in the prone position, chest rolls (pick 2) Improve venous return Increase central venous pressure reduce surgical blood loss decrease pulmonary compliance
Improve venous return reduce surgical blood loss
what risk factors increase the risk of perioperative ulnar neuropathy
Male gender cardiac surgery extremes of body habitus prolonged hospital stay undiagnosed preexisting ulnar neuropathy
what nerve can be damaged during a venipuncture
Median nerve
nerves of the foot
Nerves in the Ankle § Tibial § Saphenous § Medial Plantar § Lateral Plantar § Sural
how can permanent loss of vision occur
Permanent loss of vision can occur after nonocular surgical procedures, especially those performed in a prone position.
what are some other factors that contribute to nerve injuries
Positioning Devices § Table straps, leg holders, shoulder braces, ether screen, headrests o Length of procedure (longer than 4 hours) § possible injuries: · Postoperative visual loss - lengthy procedures in prone or steep Trendelenburg · Nerve injuries · Compartment syndrome · Rhabdomyolysis and acute renal failure o Body habitus § Obese, malnutrition, bulky musculature o Anesthetic techniques § GA, hypotensive techniques, neuromuscular blockade o Preexisting pathophysiology § Anemia, diabetes, peripheral vascular disease and neuropathies, alcoholism, smoking § Table strap = lateral femoral cutaneous
When positing a pt supine with arms abducted, forearms should be supinated to reduce undue pressure on which nerve at the mid humeral level medical radial musculocutaneous ulnar
Radial
what is the best way to place the arm if the pt is supine
1 - supination 2 - neutral 3 - pronation - this puts a lot of stress on the ulnar nerve o Nagelhout says supinated or neutral forearm position NOT PRONE
what are the 4 basic components of safe positioning. what does each mean or include?
1. Knowledge o Implies theoretical and practical understanding of the general principles of arrange an unconscious or awake patient. o Knowledge of the surgical procedure. o Appreciation of consequences for improper or incomplete attention to petty details. 2. Forethought o Understanding of the operation and the problems that face the surgeon. o Communication is important among all members. o Planning ensures that all members have time to assemble equipment. 3. Teamwork o Ensure a sufficient number of personnel present to position the patient. o The surgeon should be present. 4. Housekeeping
A suprascapular nerve injury would most likely occur due to A. ventral circumduction of the arm B. acute flexion of the hips C. abduction of the arms greater than 90 degrees D. malposition of the kidney rest
A The suprascapular nerve extends from the cervical spine to the suprascapular notch. Because it is in a fixed position at both points, rotation of the scapula outward can produce stretching of the nerve. This can occur during ventral circumduction of the arm (rotation of the arm across the front of the body as if to place the bicep against the sternum).
Which of the following would you expect to occur when placing a surgical patient in the sitting position? (select two) A. Reduction in central venous pressure B. Increase in systemic vascular resistance C. Increase in cardiac output D. Decrease in heart rate
A B When placed in the seated position, the cardiac index, pulmonary artery wedge pressure, and central venous pressure decrease substantially, but the systemic vascular resistance increases.
Which of the following would occur in the patient placed in the head-down (Trendelenburg) position? (select two) A. Central venous pressure would increase B. Intraocular pressure would decrease C. Cerebral blood flow would decrease D. Intracranial pressure would increase
A D In the Trendelenburg position, the central venous pressure, intracranial pressure, and intraocular pressures all increase. These factors can contribute to edema of facial and upper airway structures.
An inability to oppose the fifth finger and a decrease in sensation to the fourth and fifth fingers is consistent with injury to which nerve?
An inability to oppose the fifth finger and decreased sensation to the fourth and fifth fingers is consistent with injury to the ulnar nerve.
what nerve results in foot drop
Anterior tibia nerve injury & sciatic nerve injury
What nerve travels in the musculospiral groove of the humerus? A. ulnar B. radial C. median D. long thoracic nerve
B The radial nerve passes around the posterolateral aspect of the middle and lower humerus in the musculospiral groove. At about three centimeters proximal to the lateral epicondyle, it can become compressed against the humerus. This can occur due to excessive cycling of the blood pressure cuff, pressure from the vertical bar of an anesthesia screen, or even excessive compression when tucking the arms beside the torso.
What nerve passes between the medial epicondyle of the humerus and the olecranon? A. radial B. ulnar C. median D. musculocutaneous
B The ulnar nerve originates as a branch of the medial cord of the brachial plexus. It travels along the anterior aspect of the medial triceps head before passing between the medial epicondyle of the humerus and the olecranon on its way to the hand.
Extreme flexion of the thighs can result in injury to which nerve? (select two) A. Common peroneal B. Obturator C. Sciatic D. Saphenous
B C Extreme flexion at the thigh can result in injury to the sciatic, obturator, and femoral nerves.
which statements about lithotomy position are true - Pick 2 Both legs must be moved simultaneously to prevent hip dislocation the peroneal nerve can be damaged at the media aspect of the leg Extreme hip flexion can injury the sciatic nerve the saphenous nerve can be damaged at the lateral aspect of the leg
Both legs must be moved simultaneously to prevent hip dislocation Extreme hip flexion can injury the sciatic nerve
Which of the following parameters would most likely decrease when placing a patient in the Trendelenburg position? A. Pulmonary artery pressure B. Pulmonary artery occlusive pressure C. Functional residual capacity D. Central venous pressure
C In the Trendelenburg position and lithotomy positions the functional residual capacity is decreased and the central venous pressure (CVP), pulmonary artery pressure (PAP), and pulmonary artery occlusive pressure (PAOP) are typically increased. The cardiac index, stroke volume, and mean arterial pressure may not necessarily be increased even though cardiac work is increased.
In which position are the legs dependent? A. standard lateral B. supine C. lateral jackknife D. Trendelenburg
C In the standard lateral and supine positions, the legs are approximately on the same level as the heart. In the Trendelenburg position, the legs are higher than the level of the heart. In the sitting, prone, lateral jackknife, and kidney rest positions, however, the lower extremities are dependent. This can produce a decrease in cardiac output and blood pressure due to decreased venous return.
A patient placed in lithotomy position for a surgical procedure exhibits loss of dorsiflexion of the foot in the recovery area. This may indicate damage to the A. saphenous nerve B. femoral nerve C. common peroneal nerve D. sartorius muscle
C. common peroneal nerve Loss of dorsiflexion of the foot is consistent with injury to the common peroneal nerve which can occur in the lithotomy position if the lateral thigh is allowed to rest on strap supports. The femoral nerve innervates the anterior thigh and knee and the saphenous nerve, which is a branch of the femoral nerve, provides sensation to the medial aspect of the foot.
where do the dermatomes in C4 C6 C7 C8 T1 T2 go?
C4 - superior aspect of the shoulder C6 - lateral shoulder C7 = 5th digit C8 - 5th digit T1- medial aspect of the arm T2 - axilla
what interventions can help identify neurovascular compression in the dependent arm during lateral position (pick 2) Compare dependent and non dependent arm BP Check capillary refill and pulses every 10 minutes use peripheral nerve stimulator on the dependent arm Monitor dependent fingers with pulse oximetry
Compare dependent and non dependent arm BP Monitor dependent fingers with pulse oximetry
what is the MOST common cause of Perioperative eye injury Ischemic optic neuropathy corneal abrasion central retinal artery occlusion Enucleation
Corneal abrasion
damage to what nerve causes paranesthesia along the anteromedial aspect of the leg
Saphenous Nerve
ulnar nerve injury is best prevented by
forearm supination
in what position should teds be placed
in the sitting to avoid venous pooling
what are the effects of gravity in Anesthetized pt
o Body's protective mechanisms are attenuated by: § General anesthesia (impaired baroreceptor responsiveness & ↓ SNS tone) § Neuraxial anesthesia (sympathectomy) · This stops the sympathetic response which results in vasodilation = lower BP § Positive Pressure Ventilation & PEEP (↑ intrathoracic pressure → ↓ venous return) § Muscle Relaxants (↓ skeletal muscle tone → ↓ venous return) o NET RESULT: § Blood volume follows gravity
what are the most frequent nerves injured with the lateral decubitus position
o Brachial plexus - head o Ulnar - hand placement o Sciatic? o Tibia? o Common Peroneal § If arm holding device used for nondependent arm · The radial nerve may be damaged § Damage to dependent eye not adequately protected. § Permanent blindness from retinal artery thrombosis from pressure when the head is improperly placed on a headrest or pillow
what nerve can the candy cane leg holder (lithotomy) position damage
o Candy cane leg holder = can damage the peroneal nerve damage
what cases are done in a sitting position
o Cases where the lesser degree sitting position may be used in the OR: § Thyroidectomy § Transphenoidal Craniotomy § Anterior Cervical Fusions § Head & Neck Surgery
what are the 5 nerves that can be injured in lithotomy position
o Common peroneal (most commonly injured) o Sciatic o Femoral o Saphenous obturator
what are the complications of steep Trendelenburg
o Hypotension o Blood loss and hypovolemia o Venous air embolism (entrainment of air in the pelvic or abdominal veins) o Ocular complications (retinal detachment or cerebral edema) o Venous thrombosis o Endotracheal tube migration (endobronchial intubation) o Atelectasis o Neuropathy (brachial plexus dysfunction) o Arthralgia o Finger injuries o Regurgitation
what are the complications that can occur in the sitting position
o Hypotension o Endotracheal Tube & Catheter Tip Migration § (tube goes where nose goes) o Air Embolism o Unilateral Blindness o Edema of Face, Tongue & Neck o Brachial Neurovascular Injury o Sciatic Nerve Injury o Foot drop
what can happen when both legs are lowered in lithotomy position. what should you do before?
o Hypotension may occur when legs are lowered o Backache frequent complaint with both spinal and general anesthesia o Lower legs slowly and simultaneously § Chart BP once legs are down § Give fluid before to help with the pool of blood § Chart what the BP is before leg drop and after as well
Anterior Tibia Nerve How it injured result of the injury
o Nerve - Anterior Tibia § How its injured · Plantar flexion of feet for extended periods of time · Injury results from no support under the feet while sitting or no roll under ankles while prone § Result of the injury · Foot drop
Brachial Plexus Injury How is it injured What is the result of the injury
o Nerve - Brachial Plexus § How injured · Excessive abduction (over 90degres) of arm with head tuned in opposite direction · In prone position when arm is used as a level during turning · In supine/Trendelenburg position when shoulder braces are pressing medially against the root of the neck · Spreading of the sternum § Result of Injury · Weak arm function
what are the relative contraindication of Trendelenburg position
o Several pre-existing medical conditions are relative contraindications to use of the trendelenburg position. § A ruptured viscus, where free pus may be present in the abdominal cavity § A head injury or brain tumor that causes increased ICP § Congestive heart failure § A thoracic injury that compromises pulmonary physiology § Entities that cause increased intra-abdominal pressure, such as extreme obesity, pregnancy, and ascites
what results in ischemia of the nerves
o Stretching nerves 5% or more beyond their resting lengths may kink feeding arterioles and result in ischemia.
a broken fibula can cause injury to what nerve
peroneal nerve
what are the risk factors for compartment syndrome
§ Compartment Syndrome: o This is the most common in lithotomy position o Risk factors: § Increased BMI § Surgical time over 2-3 hours § Decreased tissue oxygenation (hypotension) o Other causes § Retractors § External compression of elevated extremity by poorly padded device or straps
hw do you dx a venous air embolism
§ Diagnose: · TEE · precordial doppler 3rd-6th intercostal spaces to the right of the sternum · mill wheel murmur · Notice a drop in EtCO2 seen and presence of END TIDAL NITROGEN
the face mask can damage which nerve
§ Face mask improperly placed may cause hair loss of the eyebrow. Face straps place pressure on the buccal branch of the facial nerve paralyzing the orbicularis oris muscle. There may be neurosis of the bridge of the nose.
what nerves go to the knee and what goes below the knee
§ Femoral in the back - L2,L3,L4 goes to the knee § L5 and below goes below the knee · So anything below the knee is due to sciatica injury
how can the ett move with a pt in Trendelenburg
§ Flexion of the intubated individual may cause endobronchial intubation especially in trendelenburg position § Since the diaphragm pushed up and the ett stays in the same place so the ett could be pushed in = endobronchial tubes § Endotracheal tube position may change - MAIN STEM intubation may occur § Check breath sounds after positioning and chart....
what can happen in lithotomy position A high lithotomy position Exaggerated lithotomy position
§ High Lithotomy position o Potential for angulation and compression/obstruction of contents of femoral canal o Stretch of sciatic nerve Slide 69 - Exaggerated lithotomy position o Shoulder support may be necessary o They should be padded and Placed over the acromioclavicular area
what is the Jackson and Wilson frames how do they affect pulmonary compliance and the vena cava
§ Jackson and Wilson Frames -type of prone position o Free the chest and abdomen during prone procedures. o Maintain normal pulmonary compliance- the inferior vena cava is not impaired thus optimizing venous return.
what nerve injury can happen in Lithotomy injury
§ Lithotomy Nerve Injury o Strap supports can cause numbness on medial calf = saphenous o Strap supports can cause lateral thigh compression = common peroneal (most frequently damaged)à loss of dorsiflexion of foot o Decreased sensation to lateral thigh = lateral femoral cutaneous
what position has less adverse effects on the circulation. What are the pressure points of this position
§ The supine position has less adverse effects on the circulation then that of any other surgical position. § Hypotensive episodes can contribute to decreased tissue perfusion of the weight-bearing areas, including the occiput, scapulae, sacrum, elbows, and heels. § Pressure alopecia can result if the occiput is not sufficiently padded or if the head is not repositioned at regular intervals during lengthy procedures.
What are the Cardiovascular changes in Trendelenburg and lithotomy position. where does the blood shift and what does this lead to.
§ This causes the blood to shift "towards" the central circulation § This leads to · Increased venous return · Increased venous pressure o Which has increased in hydrostatic pressure of the face, eye and airway o Intracranial pressure · Map stays the same or increased · Increased position on the frank starling curve (so a shirt to the right) § Hypovolemia may not be noticed until the legs are down
what is erbs palsy what nerves does it affect and what position can it occur in
§ Trendelenburg Position Cont o Erbs Palsy § Paralysis of group of muscles of the shoulder and upper arm § Consisting of roots C5- C6 § Arms hang, hand rotates inward and normal movement is lost
what happens if a nerve is stretched beyond their resting lengths?
· **Stretching nerves 5% or more beyond their resting lengths may kink feeding arterioles and result in ischemia
what nerve injury results in foot drop
sciatic nerve & Anterior tibia nerve
which position is MOST likely to contribute to the development of a "mil wheel" murmur? Supine sitting Prone Lateral Decubitus
sitting -25 this is a signs of a venous air embolism the next best choice would be Supine - 18% o Prone - 10 % o Lateral - 8
Which surgical positions reduce cardiac output the most (pick 2) Supine Sitting Lateral Decubitus Prone
sitting and Prone think about the position of the lower extremities in relation to the hear. in the sitting, flexed lateral , and prone positions, the lower extremities are below the level of the heart which is why they have a higher incidence of hemodynamic changes
where should the arm be with the use of the bean bag
the bean bag does not go under the arm
what position decreased the FRC the most
trendelenburg
damage to what nerve results in claw hand What is claw hand
ulnar nerve it is the impaired sensation to the 4 and 5th digits inability to abduct or oppose the pinky finger Chronic injury present with claw hand (muscular atrophy)
what are the risk factors to an ischemic optic neuropathy
§ -Ischemic Optic Neuropathy o Risk factors for intraoperative ischemic optic neuropathy in the perioperative may be attributed to: § Long duration of surgery § Prone position § Prolonged hypotension
what are the 4 mechanism responsible for nerve inquires
§ 1.Transection - cuttings through a nerve § 2. Compression § 3. Stretch - when nerves are over stretched § 4. Kinking = when the nerve is inched between two immovable structures
pick one: in what positions is the lung compliance most decreased o Lateral o Lithotomy o Prone o Trendelenburg
§ Answer: Pulmonary compliance is most decreased in the Trendelenburg position. In the lateral decubitus posn. The compliance of the dependent lung is decreased, but the compliance of the nondependent lung may increase, so overall change in pulmonary compliance is not great.
what happens the to CI CVP PCWP CO BP SVR in sitting position
§ CI = decreased § CVP = decreased § PCWP = decreased § CO= Decreased by 20% if the pt is raised to 90 degrees § BP= Decreased § SVR = decreased o BP increases or decreases by 2 mmHg every inch above or below the heart 1 cm = 0.75 mmHgor10 cm = 7.5 mmHg
what nerve is affected when you have an excessive right arm restraint
§ Can compress the anterior interosseous nerve and vessel against the interosseous membrane
what is the presentation of a common peroneal nerve injury
§ Common Peroneal Nerve Injury o Etiology § Stirrups o Presentation § Foot drop is the Inability to evert the foot and the Inability to extend the toes dorsally § ...nerve wraps around the fibular head
Ulnar nerve How is it injured What is the result of the injury
§ How it is injured · Compression between medial epicondyle of the humorous and the sharp edge of the bed or head frame § Result of the injury · Sensory loss in the 5th digit · Claw hand § The most common postoperative peripheral neuropathy
Sciatic nerve How is it injured What is the result of the injury
§ How it is injured · Lithotomy (extreme hip flexion or external rotation of the legs) · Sitting - straight legs § Result of the injury · Foot drop § How you can prevent this · Ample padding under buttocks · Avoid excessive external rotation of the hips · Flex table at the knees
what is ischemic optic neuropathy what position is it associated with. how can it be prevened
§ Ischemic Optic Neuropathy o Associated with extensive surgical procedures done in prone position. § Blood loss § Anemia § Hypotension Ischemic Optic Neuropathy o Acute venous congestion of the optic canalà reduced optic nerve perfusion pressure § Wilson surgical frame-with its elevated curvature resulting with head being lower than the heart § Obesity and elevation of intra-abdominal pressure § Long anesthetic durations § Other independent factors: male gender, increased estimated blood loss, low percent of colloid administration o Prevention = use of colloids, keep head level with or higher than heart, reduce abdominal pressure, use staging procedures to cut down on surgical time.
know these lower extremity nerve issues
§ Lower Extremity Nerve issues - Know o Anterior Tibial = foot drop o Femoral = impaired knee extension and hip flexion as well as reduces sensation over the anterior thigh and anteromedial aspect of the leg o Saphenous = paresthesia along the anteromedial side of calf o Obturator = diminished sensation over the medial side of the thigh = You have an inability to adduct the leg
what is Midcervical tetraplegia and in what position is it a major concern
§ Midcervical tetraplegia - another major concern § Caused by hyperflexion of the neck 9chin to chest) o Ischemia occurs as a result of stretching or compression of the mid-cervical spinal cord (usually C-5)
what are some miscellaneous injuries that can happen in the OR
§ Miscellaneous Injury § Fingers and toes may be injured when the operating room table is moved to reposition the patient. Ears need to be free from folds, EKG leads, and other monitoring equipment. § Face mask improperly placed may cause hair loss of the eyebrow. Face straps place pressure on the buccal branch of the facial nerve paralyzing the orbicularis oris muscle. There may be neurosis of the bridge of the nose. o The endotracheal tube connector may compress the supraorbital nerve (nasal intubation) when the breathing circuit exits over the forehead. When holding the mandible forward you may place excessive pressure on the facial nerve
how do the lung volumes change when you go from sitting to supine
§ Position change from sitting to supine o No significant change § Residual Volume § Tidal Volume § Total Lung Capacity o Decrease § Functional Residual § Capacity
what is pressure alopecia
§ Pressure alopecia can result if the occiput is not sufficiently padded or if the head is not repositioned at regular intervals during lengthy procedures.
when placing a pt in prone position what should you take into consideration what about the neck and arm mobility
§ Prone Padding and Face Rests o If the pt has limited cervical neck movement then head clamp or face rest should be used - be careful muscle relaxants will relax the muscles and allow the rotation of the head o If the pt is able to rotate their head without pain - head can be turned laterally and supported o Rotation can impair carotid and vertebral vessels Arm Placement o Preop pt should be asked if he/she can raise arms above his/her head or clasp the hands behind the head to check for thoracic outlet syndrome. o If unable to do so it may be prudent to place the arms alongside the pt's torso.
what are some of the complications of prone positioning
§ Prone Position Complications o During the Turn o OOPS - dropping the patient o Loss of airway, vascular access lines, catheters, monitors o Injury to arms o Watch out!! Injury to the attendants. o Eye and Ears o Corneal abrasion - tape o Ocular edema o Compression o Vascular Disturbances o Skeletal Distress o Stressing the Brachial Plexus o Breast Injuries o Obese Abdomen o Genitalia
where do the breast go in a prone position how can you avoid a brachial plexus injury
§ Prone Positioning o Breasts should be placed in the medial and cephalad position. o Pt with normal breasts will experience postop tenderness if the breasts are positioned laterally. o Pt with large breast may not experience pain positioned laterally. o Avoid brachial plexus injury by placing the arms alongside the head, flexed at the elbows, and abducted onto arm boards. o Direct pressure on the breasts can cause ischemia to breast tissue.
what are the most commonly injured nerve in supine position
§ SUPINE § Most commonly injured nerves involve: § brachial plexus § ulnar nerve Minimal effect on circulation and perfusion of lungs o Padding under head, elbows, sacrum, and heels. o Arm extension 90 degrees or less, palms up. If placed at side, palms down, secured with restraining sheet (above elbows, tucked under patient rather than under mattress), and elbows and fingers secured to avoid slipping off mattress edge.
how does damage to the supraorbital nerve present
§ SUPRAORBITAL NERVE o Injury occurs when compression occurs; compression results in decreased sensation over the forehead and pain in the eye
The ventral decubitus position is the same as the A. prone position B. lateral jackknife position C. supine position D. lithotomy position
The ventral decubitus position is another term for the prone position.
Which position would produce the greatest negative effects on the respiratory system in a healthy patient?
Trendelenburg The Trendelenburg position is perhaps the worst position on the ventilatory system. The abdominal contents exert an increasing pressure against the diaphragm as the steepness of the position is increased. This effect is worsened by the pressure of a pneumoperitoneum during laparoscopic surgery.
what nerve damage is the most common post operative peripheral neuropathy
Ulnar nerve - § The most common postoperative peripheral neuropathy
what are some of the complications that can occur in a prone position
damage to eyes and ischemic optic neuropathy
leg position in the lithotomy position should be limited by (Pick 2) Hip flexion between 45 and 90degrees hip flexion between 80-100 degrees leg abduction between 30 to 45 degrees from mid line leg abduction between 45 and 60 degrees from midline
hip flexion between 80-100 degrees leg abduction between 30 to 45 degrees from mid line
which are the consequences of general anesthesia in the sitting position - pick 2 High BP Vertebral artery constriction lower extremities blood pooling cerebral ischemia
lower extremities blood pooling cerebral ischemia
in a mechanically vented pt which lung will always be better ventilated
o **Mechanical ventilated - non dependent always better ventilated** o ** compromises pulmonary function most in the anesthetized/paralyzed patient
Perioperative visual loos can occur due to what bed frames/ positioning
o A Wilson frame o B. Mirror system for prone o Prone position with horseshoe o Prone position with face seen below
what does abduct and adduct mean
o Abduct - moves away from the body o Adduct - moves the extremities closer to the body o In proper position the palms of the hands will face out
§ In the anesthetized patient in the lateral position... (select 5) o A.The upper lung is ventilated more o B. The dependent lung is ventilated more o C. The upper lung is perfused more o D. The dependent lung is perfused more o E. The functional residual capacity decreases o F. A ventilation/perfusion defect occurs o G. The upper lung is shifted to a more compliant position o H. The dependent lung is shifted to a more compliant position
o Answer.. § *THE UPPER LUNG IS VENTILATED MORE § The dependent lung is ventilated more § The upper lung is perfused more § *THE DEPENDENT LUNG IS PERFUSED MORE § *THE FUNCTIONAL RESIDUAL CAPACITY § DECREASES § *F. A VENTILATION/PERFUSION DEFECT OCCURS § G. *THE UPPER LUNG IS SHIFTED TO A MORE § COMPLIANT POSITION § H. The dependent lung is shifted to a more compliant position
in an awake lateral position where do you have greater perfusion and then greater ventilation
o Awake lateral position - not sedated in a lateral position § ventilation and perfusion are greater in the dependent lung than the nondependent lung § notes from the slide · When a supine patient assumes the lateral decubitus position, ventilation/perfusion matching is preserved during spontaneous ventilation. The lower lung receives more perfusion and more ventilation than the upper lung. The former is the result of gravity; the latter occurs because (1) contraction of the dependent hemidiaphragm is more efficient as it assumes a higher position in the chest (compared with the upper hemidiaphragm) due to its disproportionate share in supporting the weight of abdominal contents and (2) the dependent lung is on a more favorable part of the compliance curve.
how does the BP change for every inch above or below the heart
o BP increases or decreases by 2 mmHg every inch above or below the heart 1 cm = 0.75 mmHgor10 cm = 7.5 mmHg o Generally 1 inch-2mmHg o 4 cm converts to 3mmHg
what is the Most frequent damaged nerve in lower extremity?
o Common peroneal nerve
Explain the mechanism of nerve injury - compression
o Compressed § When a nerve is forced against a bony prominence or a hard surface such as the arm board or operating room table o ex. § Lateral posn. - superior leg pushes against the dependent extremity and may compress the common peroneal nerve of the dependent leg against the operating room table § Radial nerve injury - improper tourniquet and BP cuff § Shoulder brace or bean bag
how should a pt be positioned in a head elevated position
o Elevation of the operative site improves venous drainage from the wound o A less severe head elevation (lawn chair or barber chair) may be used for procedures involving the neck or shoulder o Arms crossed in patient's lap for easy intravenous access, elbows flexed 90 degrees or less o Padding under buttocks, knees, heels, and elbows. § No contact between skin and metal frame o pts head is bolted to the frame so watch you vent settings you dont want them to start coughing or bucking
how can you remove an air embolism in sitting and prone position
o Entrained air emboli are removed from circulation by aspiration through a multiorifice central venous catheter § Catheter Placement: § Sitting position - place in the right atrium at the junction of the superior venous cava § Prone position - place in the junction of the inferior vena cava (IVC) and right atrium o because air emboli from the spinal surgery enter the venous circulation through the lumbar epidural veins and IVC
what nerve injuries can occur in lithotomy nerve injury
o Excessive flexion of thigh against groin = obturator or less commonly femoral o Stretch injury = sciatic § Weakness of all skeletal muscles below the knee and diminished sensation over lateral half of the leg and almost all of the foot · Foot drop · Pain or numbness of lower leg, thigh, or foot
in a asleep (GA) pt in lateral position how does GA affect the FRC
o GA decreases FRC and moves upper lung to a more favorable part of compliance curve, but moves the lower lung to less compliant position. o RESULT - V/Q mismatch ( upper lung ventilated more than the dependent lung, perfusion still better with dependent lung) o Bean bag further restrict movement, and muscle paralysis allows abdominal contents to rise against dependent hemidiaphragm and impede ventilation **Mechanical ventilated - non dependent always better ventilated** o ** compromises pulmonary function most in the anesthetized/paralyzed patient
in an general anesthesia lateral position where do you have greater perfusion and then greater ventilation
o General Anesthesia in a lateral position · (Positive ventilation and muscle relaxants) § abdominal contents shift cephalad, moving the hemidiaphragm of the dependent lung upward, decreasing ventilation and compliance - nondependent lung is better ventilated § Notes from the last slide - Induction of Anesthesia o The decrease in functional residual capacity (FRC) with induction of general anesthesia moves the upper lung to a more favorable part of the compliance curve but moves the lower lung to a less compliant position. As a result, the upper lung is ventilated more than the dependent lower lung; ventilation/perfusion mismatching occurs because the dependent lung continues to have greater perfusion.
o If FRC decreases and Residual Volume is unchanged, then the Expiratory Reserve Volume does what? o Does Inspiratory Reserve Volume (IRV) increase or decrease ?
o If FRC decreases and Residual Volume is unchanged, then the Expiratory Reserve Volume does what? § (FRC = RV + ERV) o Does Inspiratory Reserve Volume (IRV) increase or decrease ? § TLC = FRC (RV + ERV) + TV + IRV · Notes: o ERV must decrease (because FRC decreased) o IRV increases because TLC does not change, so if FRC decreases, RV remains unchanged, then IRV must increase. § Answer - No significant change: Residual Volume, Tidal Volume, Total Lung Capacity. But a Decrease: Functional Residual Capacity § ERV must decrease (because FRC decreased) § IRV increases because TLC does not change, so if FRC decreases, RV remains unchanged, then IRV must increase.
Explain the mechanism of nerve injury - kinking
o Kinking § When peripheral nerve is pinched between two immovable structures · Ex. Femoral nerve can be kinked under the inguinal ligament when the thighs are flexed on the abdomen, as in exaggerated lithotomy position
where should the kidney rest be in a lateral jack knife position. what is the complication of the kidney rest
o Lateral jackknife with elevated kidney rest o Kidney rest should lie under the dependent iliac crest o Complication of the Kidney rest is compression of the inferior vena cava causes: § decreased venous return § decreased BP - hypotension § Venous pooling
What is compartment syndrome
o Life threatening complication causing damage to NEURAL AND VASCULAR structures from tissue swelling from increased pressure and decreased tissue perfusion in muscles with tight fascial borders § Dubbed "reperfusion injury" (when blood flow returns after ischemia) o This is the most common in lithotomy position
what injuries results due to a brachial plexus nerve damage
o Median - "ape hand" deformity o Axillary - inability to abduct arm o Ulnar - claw hand deformity (inability to abduct the fifth finger) o Musculocutaneous - inability to flex forearm o Radial - wrist drop
what can you do to promote cardiovascular stability when moving a pt
o Move the pt slowly o Use lighter plan of anesthesia o IV Hydration
Femoral Nerve How it injured result of the injury
o Nerve - Femoral § How its injured · Extensive Traction during lower abdominal surgery · In lithotomy position, extreme abduction of the thighs with external rotation of the hip · Compression at pelvic brim by retractor of excessive angulation of the thigh · diabetes mellitus - careful with poisoning - femoral neuropathy § Result of the injury · Impaired knee extension and hip flexion · Decreased sensation over anterior thigh an anteromedial side of the leg
Obturator nerve injury How it injured result of the injury
o Nerve - Obturator Nerve Injury § Etiology · Excessive flexion of the thigh toward the groin · Excessive traction during lower abdominal surgery · Forceps delivery § Presents: · Inability to ADDuct the leg · Reduced sensation over medial aspect of thigh § Prevent · Minimize hip flexion
Pudenal Injury How is it injured What is the result of the injury
o Nerve - Pudendal injury § How injured · Injury occurs when the nerve is compressed against the perineal post on an orthopedic fracture table § Result of Injury · Loss of perineal sensation o Nerve - Brachial Plexus § How injured · Excessive abduction (over 90degres) of arm with head tuned in opposite direction · In prone position when arm is used as a level during turning · In supine/Trendelenburg position when shoulder braces are pressing medially against the root of the neck · Spreading of the sternum § Result of Injury · Weak arm function
Radial nerve How is it injured What is the result of the injury
o Nerve - Radial § How it is injured · Compression against underlying humorous when lateral upper arm is compressed on the OR table § Result of the injury · Inability to extend the wrist · Inability to abduct the thumb · Wrist drop · Decreased sensation over the dorsal surface of the lateral three and 1 half fingers
Saphenous Nerve How it injured result of the injury
o Nerve - Saphenous § How its injured · In lithotomy position, damage occurs when medial aspect of the lower leg is suspended outside the unpadded support · Or when leg leans against supporting cradle in lithotomy position · Saphenous Nerve resides near the tibia § Result of the injury · Paranesthesia along anteromedial aspect of leg
Median Nerve How is it injured What is the result of the injury
o Nerve = Median · How it is injured Indiscriminate probing in the antecubital fossa during VENIPUNCTURE § Result of the injury · Loss of sensation of fingertips · Inability to oppose the first and fifth digits · Deceased sensation on the palmer surface of the lateral three and one-half fingers § This is NOT USUALLY due to a compression injury
in a lateral decubitus position where does the axillary roll go
o Place roll (AXILLARY) under thorax just caudal to dependent axilla **chart this! § relieves pressure exerted on the shoulder, axillary vessels, and brachial plexus of the dependent arm o Check perfusion of dependent arm o Pillow under: § head § between knees § under the dependent knee
what position do you have more uniform and VQ match is better
o Prone - is more uniform and VQ matching is better o Ventilation is more uniform and V ̇ /Q̇ matching is better in the prone position than in the supine position due to the alleviation of pressure from the anterior structures on the posterior lung tissue
what are the pressure points in a prone position what should you do when a pt is in a prone position
o Prone position = In the prone or ventral decubitus position, the patient lies down with the ventral body surface areas as support § PRONE POSITION o Maintain proper position of the head and avoid eye pressure o Pad the ulnar nerve o Pad the knees o Support the chest & iliac region o Support the feet and shins This helps favor venous drainage, knee support and pressure points at the hips
in what procedures is steep Trendelenburg used
o Robotic Procedures § Prostatectomies § Colorectal Gynecological
what are the key points of the prone position
o Rotate from supine to lateral to prone with adequate personnel o Arms extended above head-well padded armboards parallel to table o minimal abduction and extension of the upper arm with elbow flexion o NO PRESSURE ON: § humeral head into axillary neurovascular bundle § Axilla § Elbow o Check pulses at wrist
what Nerve is damaged inside knee when compressed?
o Saphenous nerve
how should pts be positioned before surgery?
o Sedated or anesthetized patients should be placed in positions that are comfortable while they are awake.
what is the major injury for a pt in Trendelenburg
o Shoulder braces- Place shoulder braces (if used) at acromioclavicular joint o Because of Brachial plexus palsy they are not routinely used anymore. o Currently, a non-sliding mattress is safer
what are the incidence of venous air embolism in sitting supine prone lateral
o Sitting - 25% o Supine - 18% o Prone - 10 % o Lateral - 8 o Also think about the C section where the pull out the uterus and it is higher than the heart so there is a chance of an air embolism
What are the Cardiovascular changes in sitting, flexed lateral and prone positions. where does the blood shift and what does this lead to.
o Sitting, flexed lateral and Prone positions § This shifts blood "from" the central circulation · This results in o Decreased venous return o Decreased position on the frank starling curve
Explain the mechanism of nerve injury - stretching or traction
o Stretching or Traction § When nerves such as the sciatic nerve or brachial plexus (fixed at two locations) have a long course across many structures § Ex Abducted greater than 90 degrees &/or head rotated to one side **Stretching nerves 5% or more beyond their resting lengths may kink feeding arterioles and result in ischemia
in a awake and lateral position which lung is better ventilated and perfused
o The dependent lung is better ventilated and better perfused than the non dependent lung. o The diaphragm counteracts most of the pressure by the abdominal contents.
what surgeries used lateral decubitus position
o The lateral decubitus Used with: § Orthopedics § Hips § Shoulder § Thoracotomy § Cardiac § Thoracic-vascular § Gastroesphageal pathology
where are the shoulder supports placed in an exaggerated lithotomy position
o They should be padded and Placed over the acromioclavicular area
in what position is compartment syndrome most commonly occur in
o This is the most common in lithotomy position
what nerves for the foot are compressed with the legs crossed
o Top leg will injury the sural nerve § Pressure from the superior aspect of the depended leg will damage the sural nerve on the underside of the superior leg o Bottom leg = results in superficial peroneal injury § Pressure form the underside of the superior leg will damage the superficial peroneal nerve of the depended leg
how does turning the head affect jugular venous drainage
o Turning head may obstruct jugular venous drainage and vertebral artery blood flow
what is the Most common injured nerve during anesthesia?
o Ulnar nerve
what is the major concern/complication of the sitting position
o Venous air embolism is a major concern § Occurs from a negative pressure gradient exists between the right atrium and the veins at the operative site · Air that enters the right side of the heart limits gas exchange in the lungs as it displaces blood in the pulmonary vasculature § Diagnose: · TEE · precordial doppler 3rd-6th intercostal spaces to the right of the sternum · mill wheel murmur · Notice a drop in EtCO2 seen and presence of END TIDAL NITROGEN
how is the Vital capacity affected in a lateral decubitus
o Vital Capacity decreases 10 % o comparable to the decrease in vital capacity in the supine position
what is the effect of lithotomy position on the vital capacity
o Vital capacity decreases 18% from standing position o Pulmonary edema may occur with cardiac disease due to 600 ml blood from legs move to pulmonary system
know this Spirogram chart
o inspiratory reserve volume (IRV) § This is the max additional volume that can be inspired above VT · 300ml o Tidal volume (VT) - each normal breath = 500ml o Expiratory reserve volume (ERV) § Max volume that can be expired below VT · 1100 ml o Residual Volume (RV) § Volume remaining after max exhalation · 1200ml
what nerve injury results in the inability to ADDuct the leg
obturator nerve injury
which pt position is the best for maintenance of pulmonary function under general anesthesia supine lateral prone sitting
prone
