ssfety and positioning

Question 1

Erect to supine position causes increased venous return which presents as:

Answer 1

increased preload, stroke volume (SV), cardiac output (CO), increased MAP

Question 2

MAP maintained within a narrow range during postural

changes in

Answer 2

NON-ANESTHETIZED setting.

Question 3

GA, muscle relaxation, +pressure
ventilation and regionals interfere with
autoregulation causing

Answer 3

anesthetized patients more vulnerable to CV effects
related to positioning.
• HR, CO and BP decreased d/t CV and CNS
depression

Question 4

when should positioning be delayed?

Answer 4

when pt is unstable

Question 5

MAP decreases ___ per inch change
between the heart and a body region.

Answer 5

2 mmHg

Question 6

what position exacerbates negative response r/t respiratory

Answer 6

trendelenburg

[even worse with insufflation]

Question 7

Perioperative Contributing Factors to nerve injury

Answer 7

positioning devices
length >4 hrs
anesthetic techniques

Question 8

GA, NMB, regional risks to nerves?

Answer 8

GA = loss of pain response
NMB = increased mobility and stretching
Decreased MAP = decreased neuronal perfusion
Regional can cause injury but mostly d/t
technique, hematoma or needle trauma.

Question 9

patient related contributing factors to injury?

Answer 9

underweight
obese
muscular
HTN, DM, PVD, alcoholism, smoking

Question 10

Most frequently reported injury after surgery

and anesthesia; most commonly injured nerve.

Answer 10

ulnar nerve

Question 11

Increased incidence of ulnar nerve injury?

Answer 11

male,
preexisting neuropathy,
prolonged hospital stay,
extreme body habitus

Question 12

how to Avoid Ulnar Nerve Injury?

Answer 12

• Padding, PADDING, PADDING
• Supinate when possible
• Abduct arms < 90 degrees
• With armboards, supinate forearms
• When tucked, arms neutral with palms inward
• Avoid extensive elbow flexion

Question 13

Risk with all positions but especially
with arms over the head, abducted
and/or head rotated.

Answer 13

Brachial Plexus Injury

Question 14

Brachial Plexus Injury causes

Answer 14

• Poorly positioned axillary rolls
  • Positioning devices such as arm boards (falling off) or
  shoulder braces (steep T-burg)
  • Sternal retractors during cardiac surgery

Question 15

Most reported neuronal injury, really the second.
Primarily with regional
techniques with anticoagulants
and for pain management

Answer 15

Spinal

Cord Injury

Question 16

Spinal Cord Injury can cause

Answer 16

Hemiparesis and quadriplegia

with sitting position (rare)

Question 17

how to avoid spinal cord injury?

Answer 17

Avoid hyperflexion of neck
(2 fingerbreadths)
• Consider SSEPs, MEPs.

Question 18

Radial or Circumflex nerve injury causes

Answer 18

Ether screen, retractor pole

Question 19

Suprascapular nerve injury causes

Answer 19

Lateral position, dependent arm

with shoulder circumducted

Question 20

Sciatic nerve injury causes

Answer 20

Inadequate padding supine or sitting

Question 21

Common peroneal, Posterior tibial, Saphenous nerve injury causes

Answer 21

Lithotomy stirrups, bar, knee support

Question 22

Obturator nerve injury

Answer 22

Lithotomy with excessive hip flexion

Question 23

Pudendal nerve injury cause

Answer 23

Traction against perineal post of

fracture table

Question 24

Postoperative Visual Loss (POVL) causes

Answer 24

• Ischemic Optic Neuropathy (ION)
• Central Retinal Artery Occlusion 
(CRAO)
• Central Retinal Vein Occlusion
• Cortical Blindness
• Glycine Toxicity

Question 25

account for 81% of all POVL cases

Answer 25

Ischemic Optic Neuropathy (ION)
• Central Retinal Artery Occlusion
(CRAO)

Question 26

accounts for 89% POVL after prone spinal cases

Answer 26

Ischemic Optic Neuropathy (ION)

Question 27

Central retinal and posterior
ciliary arteries are
“watersheds” and highly
vulnerable to obstructed
blood flow

Answer 27

Ischemic Optic Neuropathy (ION)

Question 28

Predisposing Factors: Ischemic Optic Neuropathy (ION)

Answer 28

Male, HTN, CV dz, obesity, DM
• Spinal surgery, prone, long
surgery time, high blood
loss, low HCT, SBP < 100

Question 29

Most common cause: ION?

Answer 29

decreased perfusion

Question 30

Central Retinal Artery Occlusion

(CRAO) causes

Answer 30

CP Bypass, hypotension,

increased extraocular pressure

Question 31

Central Retinal Vein Occlusion causes

Answer 31

Hypertension, CV dz, obesity,

glaucoma, Sickle Cell anemia

Question 32

Results from
ischemia or trauma from emboli,
CP bypass, decreased perfusion

Answer 32

cortical blindness

Question 33

L-arginine deficiency = accumulated ammonia =           
vision loss (very rare syndrome)

Answer 33

Glycine toxicity:

Question 34

Well-known complication of
sitting position but can occur
anytime the surgical sight is above
the right atrium.

Answer 34

Venous Air

Embolism (VAE)

Question 35

Up to 35% patients with venous embolism have

Answer 35

have an undiagnosed patent foramen ovale (PFO).

Question 36

Paradoxical air embolism (PAE)

occurs

Answer 36

through a PFO when RA

pressure >LA pressure

Question 37

Small VAEs can be absorbed BUT

large VAEs cause

Answer 37

hypotension,
dysrhythmias, CV arrest, death.
• VAEs can be aspirated through
CVL placed in the RA at the junction of the SVC

Question 38

gold standard to monitor for VAEs?

Answer 38

Transesophageal Echo (TEE)

Question 39

most used way to monitor for VAEs, r/t cost

Answer 39

Precordial Doppler
• Probe over 3rd – 6th intercostal
space, R of sternum