Week 14 - Nagelhout C. 23 high yields

Question 1

What is the goal of positioning for anesthesia and surgery?

Answer 1

Optimize surgical access while minimizing risk to the patient.

Question 2

What are the risks of surgical positioning?

Answer 2

Every position has inherent risks, especially under anesthesia.

Question 3

How does general anesthesia affect the cardiovascular system?

Answer 3

Decreases cardiac output and blood pressure due to myocardial depression and vasodilation.

Question 4

What are the hemodynamic effects of the prone position?

Answer 4

↑ CVP, ↓ left ventricular volume, possible ↓ CI depending on frame.

Question 5

What is the hemodynamic risk in the sitting position?

Answer 5

↓ CO by 20% at 90° due to pooling in extremities.

Question 6

What are the attenuation methods for hemodynamic changes?

Answer 6

Slow positioning, light anesthesia (<0.5 MAC), volume loading, gradual anesthetic deepening.

Question 7

What is the cardiovascular effect of the Trendelenburg position?

Answer 7

↑ CVP and PAP, but variable effect on MAP and CI; may mask hypovolemia.

Question 8

What are the risks of combining Trendelenburg and lithotomy positions?

Answer 8

Apparent normal MAP despite hypovolemia; risk of lower extremity ischemia in PVD patients.

Question 9

What are the risks associated with the head-down position?

Answer 9

Facial, pharyngeal, and orbital swelling; ↑ ICP; POVL risk due to ↓ ocular perfusion pressure.

Question 10

What is the respiratory risk in the Trendelenburg position?

Answer 10

↓ FRC due to cephalad diaphragm displacement; risk of right mainstem intubation.

Question 11

What is the respiratory benefit of the prone position?

Answer 11

Improved V/Q matching; posterior lung better ventilated; FRC may increase if abdomen hangs free.

Question 12

What causes V/Q mismatch in the lateral decubitus position?

Answer 12

Positive pressure ventilation favors nondependent lung ventilation; dependent lung perfused more.

Question 13

What is the respiratory effect of lithotomy position?

Answer 13

Minimal in healthy patients, but extreme flexion compresses abdomen and ↓ compliance.

Question 14

What is the respiratory advantage of the sitting position?

Answer 14

↑ FRC, better diaphragmatic movement; rib cage contributes more to ventilation.

Question 15

What are the primary nerve injury mechanisms?

Answer 15

Transection, compression, stretch.

Question 16

What causes common peroneal nerve injury?

Answer 16

Compression against table in lateral position or stirrups in lithotomy.

Question 17

What are the risk factors for ulnar nerve injury?

Answer 17

Male gender, elbow flexion >90°, pronation, prolonged hospitalization, extremes of body habitus.

Question 18

What positions are at risk for brachial plexus injury?

Answer 18

Supine >90° arm abduction, Trendelenburg, prone overhead arm extension, lateral arm rotation.

Question 19

What position risks sciatic nerve stretch injury?

Answer 19

Lithotomy with hip flexion >90°.

Question 20

What are the risk factors for compartment syndrome?

Answer 20

Lithotomy >2-3 hours, Trendelenburg, hypotension, leg elevation.

Question 21

What are the major causes of POVL?

Answer 21

ION (anterior/posterior), CRAO; often related to prone position and long surgeries.

Question 22

What are the risk factors for ION?

Answer 22

Male, obesity, surgery >5 hrs, anemia, blood loss, hypotension.

Question 23

What causes CRAO?

Answer 23

External eye pressure, improper head positioning.

Question 24

What position is at risk for venous air embolism (VAE)?

Answer 24

Sitting position; occurs with negative pressure gradient between heart and veins.

Question 25

What are the detection methods for VAE?

Answer 25

TEE (most sensitive), precordial Doppler, ETCO₂ ↓, mill-wheel murmur.

Question 26

What are the methods for preventing perioperative neuropathy?

Answer 26

Proper padding, neutral positioning, avoid arm abduction >90°, supinate forearms.

Question 27

What are the ASA recommendations for arm position?

Answer 27

Supine: abduct <90°, forearm supinated/neutral. Lateral: pad axilla, monitor perfusion.

Question 28

What is the risk of arm injury in Trendelenburg position?

Answer 28

Shoulder braces can compress brachial plexus; should be placed over distal clavicle.

Question 29

What should be considered for the abdomen in the prone position?

Answer 29

Abdomen should hang freely to reduce venous pressure and bleeding risk.

Question 30

What is the airway complication risk in Trendelenburg position?

Answer 30

Risk of right mainstem intubation due to diaphragm displacement.

Question 31

Why is anesthesia documentation important?

Answer 31

Accurate records support quality care and legal protection in case of complications.

Question 32

What are the considerations for the supine position?

Answer 32

Head neutral, arms tucked or on padded armboards <90°, uncrossed legs, heels elevated, pillow under knees.

Question 33

What are the nerve injury risks associated with the supine position?

Answer 33

Ulnar and brachial plexus injuries from poor arm positioning or padding.

Question 34

What are the benefits of the Trendelenburg position?

Answer 34

Increases venous return for hypotension and improves surgical exposure.

Question 35

What complications can arise from the Trendelenburg position?

Answer 35

Increased intracranial pressure (ICP), facial/oropharyngeal edema, risk of brachial plexus injury from shoulder braces.

Question 36

What is a safety tip for the Trendelenburg position?

Answer 36

Avoid shoulder braces if arms are on armboards; brace over acromioclavicular joint.

Question 37

What is a consideration for the reverse Trendelenburg position?

Answer 37

Risk of hypoperfusion to the brain; monitor cerebral perfusion.

Question 38

What is the lithotomy position used for?

Answer 38

Perineal surgeries; legs flexed and elevated in stirrups.

Question 39

What is the safety rule for raising/lowering legs in the lithotomy position?

Answer 39

Raise/lower legs simultaneously to prevent spinal torsion and hip dislocation.

Question 40

What are the nerve injury risks in the lithotomy position?

Answer 40

Peroneal, saphenous, femoral, obturator, and sciatic nerves.

Question 41

What is the hemilithotomy position?

Answer 41

One leg elevated; arm on that side may be crossed over chest—watch for crush injury.

Question 42

What is the prone position used for?

Answer 42

Spine, rectal, and some orthopedic surgeries.

Question 43

What are the key considerations for prone positioning?

Answer 43

Abdomen hangs free; arms flexed <90°, neck in neutral, eyes protected from pressure.

Question 44

What is a risk associated with the prone position?

Answer 44

Postoperative visual loss (POVL) from venous congestion, increased intraocular pressure, airway edema.

Question 45

What is the sitting position used for?

Answer 45

Neurosurgery, shoulder surgery; excellent exposure and venous drainage.

Question 46

What complications can arise from the sitting position?

Answer 46

Venous air embolism (VAE), hypotension, paradoxic air embolism (PAE) in patients with PFO, airway edema from neck flexion.

Question 47

What is lateral decubitus positioning used for?

Answer 47

Thoracic, kidney, and some orthopedic procedures.

Question 48

What are the safety measures for lateral arm & leg positioning?

Answer 48

Dependent arm on padded board, axillary roll caudad to axilla, pillow between legs.

Question 49

What are the three primary nerve injury mechanisms?

Answer 49

Transection, compression, stretch.

Question 50

What are the symptoms of ulnar neuropathy?

Answer 50

Inability to oppose 5th finger, sensory loss in 4th/5th fingers, claw hand if prolonged.

Question 51

How can ulnar nerve injury be prevented?

Answer 51

Supinate/neutral forearm, avoid elbow flexion >90°, pad elbows.

Question 52

What are the risks for brachial plexus injury?

Answer 52

Arm abduction >90°, head rotation, shoulder depression, falling arms.

Question 53

What is a common cause of peroneal nerve injury?

Answer 53

Compression at fibular head by stirrups or table.

Question 54

What is the risk of sciatic nerve injury?

Answer 54

Lithotomy position with extreme hip flexion.

Question 55

What is the risk associated with suprascapular nerve injury?

Answer 55

Lateral position with shoulder roll without stabilization.

Question 56

What is the risk for radial/circumflex nerve injury?

Answer 56

Arm pressed against hard surface or vertical post.

Question 57

What is the risk of femoral nerve injury?

Answer 57

Extreme hip flexion (lithotomy) compresses under inguinal ligament.

Question 58

What causes posterior tibial/saphenous/pudendal nerve injury?

Answer 58

Leg holders or perineal post compression.

Question 59

What causes peripheral nerve ischemia?

Answer 59

Stretch, compression, or capillary perfusion compromise from pressure.

Question 60

What effect does stretch injury have on nerves?

Answer 60

May disrupt axons or blood supply, causing conduction block or infarction.

Question 61

What is POVL?

Answer 61

Postoperative visual loss; visual defects up to total blindness.

Question 62

What are the top two causes of POVL?

Answer 62

Ischemic optic neuropathy (ION) and central retinal artery occlusion (CRAO).

Question 63

What are the risk factors for ION?

Answer 63

Male, obesity, long surgery (>5 hrs), anemia, hypotension, Wilson frame, diabetes.

Question 64

What is the main cause of CRAO?

Answer 64

External pressure on the eye due to poor head positioning.

Question 65

What are the prevention strategies for POVL?

Answer 65

Neutral head, avoid face pressure, monitor hematocrit/blood pressure, inform high-risk patients.

Question 66

What positions carry a risk of airway edema?

Answer 66

Prone, Trendelenburg, sitting (with excessive neck flexion).

Question 67

What causes macroglossia in the sitting position?

Answer 67

Jugular venous obstruction due to head flexion.

Question 68

What positions increase the risk of right mainstem intubation?

Answer 68

Trendelenburg or neck flexion.

Question 69

What is a risk factor for compartment syndrome?

Answer 69

Lithotomy >2–3 hrs, leg elevation, hypotension, tight compartments.

Question 70

What are the signs of compartment syndrome?

Answer 70

Increased pressures, ischemia, muscle/nerve infarction, risk of renal failure.

Question 71

What position is associated with VAE risk?

Answer 71

Sitting; air enters venous system due to pressure gradient.

Question 72

What are the detection tools for VAE?

Answer 72

Transesophageal echocardiography (TEE) (most sensitive), precordial Doppler, end-tidal CO₂ decrease, mill-wheel murmur.

Question 73

What is PAE?

Answer 73

Paradoxic air embolism; risk in patients with PFO; air enters systemic circulation under pressure shift.

Question 74

What is the maximum safe arm abduction in the supine position according to ASA?

Answer 74

<90°; prone may tolerate >90° with support.

Question 75

What should be documented in positioning?

Answer 75

Record all actions for quality improvement and legal support.

Question 76

What are the key ASA upper extremity tips?

Answer 76

Supinate forearm, neutral elbow, avoid elbow flexion when tucked.

Question 77

What are the key ASA lower extremity tips?

Answer 77

Avoid fibular head pressure, assess hip/knee flexion, pad pressure points.

Question 78

What are the key areas of litigation according to CRNA/AANA claims insight?

Answer 78

Nerve injuries, brain injury, and POVL.

Question 79

What is the top nerve injury in closed-claims?

Answer 79

Ulnar (28%), brachial plexus (20%), spinal cord (13%).

Question 80

What is the trend over time for ulnar nerve injury claims?

Answer 80

Decreasing; spinal cord injury claims are increasing.

Question 81

What percentage of quality of care judgments (ASA) were deemed appropriate in spinal cord damage cases?

Answer 81

Only 46%.

Question 82

What is the preventive theme across guidelines?

Answer 82

Meticulous positioning, padding, and monitoring.