Positioning - Basics Of Anesthesia

Front 1

Should positioning be delayed if pt is hemodynamically unstable?

Back 1

duhhhh
ya

Front 2

What are the effects of gravity to respiratory system?

(2)

Back 2

1. increases perfusion to posterior (dependent) lung segments
2. decreases FRC (abdominal viscera against diaphragm)

Front 3

In horizontal supine postition does MAP stay stable?

Back 3

Yes
venous return affected only from intrathroacic pressure changes from respirations

Front 4

Which position increase pressure in cerebral veins, inc ICP/CVP/IOP, inc preload, and causes nasal congestion?

Back 4

Trendelenburg

Front 5

What nerves cause inc preload, activate aortic and carotid baroreceptors to inc parasympathetic flow and dec HR, CO?

Back 5

Vagus
Glossopharyngeal

Front 6

Trendelenburg positon causes swelling where?

Back 6

head
neck
possible airway obstruction

Front 7

What happens when abdominal viscera moves cephalad in trendelenburg position?

Back 7

decreased FRC
decreased pulmonary compliance
atelectasis
V/Q mismatch (shunting)

Front 8

What does reverse trendelenburg cause?

Back 8

1. venous pooling to lower ext.
2. decreased preload, co, perfusion
3. increased FRC, less work of spont. breathing

Front 9

Name 2 uses for trendelenburg position.

Back 9

1. improve surgical exposure
2. prevent venous air emboli
(not really useful in hypotension)

Front 10

What works better for hypotension than trendelenburg (per lecture)?

Back 10

raising legs increases MAP without affecting CO, pulmonary fx, or ICP

Front 11

In standard lithotomy position how is pt positioned?

Back 11

thighs flexed approx 90 deg.
knees bent parallel to floor
legs well padded
arms tucked or on armboards <90 angle

Front 12

Common injury with lithotomy position?

Back 12

peroneal nerve injury from fibula pressing against candy canes

Front 13

What does standard lithotomy postition do to cardiac/resp?

Back 13

1. inc preload and CO
2. dec. vital capacity, FRC, TV
3. possible hypotension when legs come down to supine

Front 14

How far are hips flexed in low lithotomy position?

Back 14

30-45%
allows simultaneous access to perineum and abdomen

Front 15

Why use high lithotomy position?
Where are thighs in this position?

Back 15

improve access to the perineum

thighs flexed 90 degrees over trunk, legs almost fully extended suspended from sling

Front 16

Explain exaggerated lithotomy position.

Back 16

1. thighs flexed over trunk
2. lower legs aimed skyward
3. symhysis ubis parallel to floor
4. may restrict ventilation
5. uphill gradient for perfusion of legs --> can cause hypotension

Front 17

Which position is associated with high incidence of lower extremity compartment syndrome?

Back 17

exaggerated lithotomy

can cause ischemia and edema

Front 18

What are the complications of dorsal decubitus positions?
(supine, frog leg, lithotomy)
(5)

Back 18

1. postural hypotension
2. pressure alopecia (use donut)
3. ischemic necrosis under bony areas
4. backache
5. nerve palsies

Front 19

Most common peeps that get peroneal nerve injury.

Back 19

smokers
low body mass index
long surgeries (>2 hrs)
also with candy canes

Front 20

Complications of lithotomy position

Back 20

1. peroneal nerve injury
2. compartment syndrome
3. digit amputation

Front 21

What is lateral decubitus?

Back 21

-turned to one side
-down side knee bent, pillow between the legs
-axillary roll caudad from axilla to raise thorax and prevent shoulder compression

Front 22

Why use an axillary roll in lateral decub position?

Back 22

to raise the thorax and prevent shoulder compression and brachial plexus injury

Front 23

under GETA dependent lung gets MORE/LESS perfusion than ventilation

Back 23

MORE

decreased compliance/atelectasis

Front 24

under GETA non-dependent lung gets MORE/LESS ventilation than perfusion

Back 24

MORE

underperfused, overventilated

Front 25

Most accurate NIBP is in dependent/non-dependent arm
(in lateral position)

Back 25

dependent

Front 26

What is lateral jackknife position?

Back 26

-intended to widen intercostal spaces
-pt down-side iliac crest over the hinge
-table is flexed so the thighs become lateral to the trunk
-chassis of table re-oriented so that flank and thorax become horizontal

Front 27

What is different about the kidney lateral jackknife?

Back 27

elevation of the "kidney rest" under dependent iliac crest to increase lateral flexion

Front 28

Complications of lateral decub positions
(5)

Back 28

1. backache/neck pain
2. compartment syndrome
3. contusion "folding" ear
4. Inc IOP, ischemia to dependent eye
5. stretch injury to suprascapular nerve (too much rotation of non-dep arm)

Front 29

What surgical access is possible with prone position?

Back 29

posterior fossa of skull
posterior spine
buttocks
perirectal area
posterior lower extremities

Front 30

In what postion can you have compression of the great vessels? why does this matter?

Back 30

Prone
b/c decreased preload

Front 31

Improper prone positioning can cause abdominal pressure.. why does this matter?

Back 31

increased abdominal pressure can cause
decreased preload
cephalad movement of the diaphragm
decreased FRC and compliance
increased peak airway pressure

Front 32

What can extreme head flexion cause in the prone position?

Back 32

may impede cerebral venous return

Front 33

Complications of prone position

Back 33

1. ischemic optic neuropathy
2. central retinal artery occulsion

Front 34

Which are you more likely to recover vision from?
Ischemic otic neuropathy
Central retinal Art. Occulsion

Back 34

ION

Front 35

Risk factors for blindness with prone position?
(surgery risk fx)

Back 35

prolonged spinal procedures
massive blood loss
intra-op hypotension
excessive crystalloid use
anemia or hemodilution
venous congestion
edema of the head
(higher MAP in spine room)

Front 36

Risk factors for blindness with prone position?
(pt risk fx)

Back 36

HTN
DM
morbid obesity
atherosclerosis
smoking

Front 37

Complications of prone position

Back 37

1. periorbital, conjunctival edema (keep HOB at lvl of heart of higher)
2. brachial plexus injury
3. impaired cerebral perf
4. breast injury

Front 38

What is sitting position for?

Back 38

posterior cervical access
posterior fossa access
shoulder operations with upper torso rotations

Front 39

Describe the sitting position.

Back 39

semireclining
legs above heart lvl
head flexed ventrally
distance b/w chin and suprasternal notch (2 fingerbreaths)

Front 40

Hemodynamic effects of sitting postion

Back 40

1. venous pooling - hypotension
2. dec. atrial filling activates RAAS
3. MAP reading at circle of willis more accurate (CPP)

Front 41

Complications of sitting postion

Back 41

1. postural hypotension
2. air embolus
3. Midcervical tetraplegia
4. edema of face, tongue, neck
5. pneumocephalus

Front 42

Who is ulnar neuropathy more common in?

Back 42

older males

can have delayed onset (3-4 days)

Front 43

Wrist drop, weakness of abduction of thumb, loss of sensation b/w thumb and index finger, inability to extend the distal phalanx of the thumb

Back 43

radial nerve injury

Front 44

inability to completely extend elbow, numbness over dorsal and palmar areas of the distal phalanges of the 1 and 2nd fingers. caused by AC trauma s/p IV attempt.

Back 44

Median nerve dysfunction

Front 45

What is Median nerve and artery damage caused by?

Back 45

tight arm restraint
ischemic injury that resembles compartment syndrom and requires surgical decompression

Front 46

Sensory neuropathy

Back 46

usually resolves 5 days

Front 47

motor neuropathy

Back 47

neurologist should be consulted
EMG studies done