Monitoring Depth of Anesthesia

Question 1

anesthesia is a controlled and reversible loss of

Answer 1

consciousness (cortical and subcortical activites)

nociception (subcortical activity)

mobility (ventral horn)

Question 2

when monitoring depth of anesthesia

Answer 2

both coritcal and subcortical activites need to be assessed

Question 3

T/F 3x more anesthetic is needed to inhibit movement then to inhibit consciousness

Answer 3

True

if patient does not move it is extremely unlikely to be conscious

Question 4

subcortical acitivites and reflexes

Answer 4

eye movement and position

eyelid, eyelash and corneal reflexes

pupillary light reflex

jaw and tongue tones

anal tone and reflex

muscle tone

repiratory/ pulse rate and rhythm

response to nociceptive stimulus

Question 5

the subcortical activities and reflexes are evaluating

Answer 5

brainstem

craninal nerves

spinal cord reflexes

automonic nervous system

Question 6

T/F during neuromuscular blockade immobility cannot be used to ensure unconsciousness

Answer 6

True

Question 7

how can cortical activity (consciousness) be monitored during neuromuscular blockade

Answer 7

end-tidal anesthetic % can be measured

EEG or BIS monitor can be used

Question 8

T/F EEGs give information about coritcal but not subcortical activites

Answer 8

True

Question 9

T/F EEGs correlate with aesthetic depth but does not predict arousal (or movement) in response to noxious stimulus

Answer 9

True

nociception is a subcortical function

Question 10

stages of anesthesia are based on:

Answer 10

observing subcortical brain activities and reflexes

Question 11

stage 1

Answer 11

voluntary movement

drug administration → loss of consciousness

pupillary dilation, tachycardia, irregular breathing

Question 12

stage 2

Answer 12

involuntary movement (excitement phase)

loss of consciousness → onset on regular breathing

tachycardia, pupillary dilationm strong palpebral and eyelash reflexes

strong jaw tone - intubation not possible/difficult

Question 13

Stage 3

Answer 13

general anesthesia

onset of regular breathing → cessation of effective breathing

no movement in response to noxious stimuli

progessvie muscle relaxation, loss of reflexes and respiratory depression

Question 14

stage 3 plane 1

Answer 14

light anesthesia

nystagmus, weakend palpebral and corneal reflexes

simple procedures/examinations may be possible

Question 15

stage 3 plane 2

Answer 15

medium plane of anesthesia

weak palpebral, strong corneal reflexes

adequate muslce relaxation for most surgical procedures

Question 16

stage 3 plane 3

Answer 16

deep anesthesia

no palpebral/corneal reflexes

some patients may have to be maintained at this stage but ideally should decrease to plane 2

Question 17

stage 4

Answer 17

overdose

respiratory failure, cardiac arrest, death from overdose

Question 18

T/F cardiovascular adverse effects are possible even if isoflurane is not overdosed

Answer 18

True

Question 19

T/F overdosing isoflurane may not always cause hypotension, shock and death (or not as soon)

Answer 19

True

Question 20

T/F if hypotension is concerning, anesthetic administration may have to be decreased regardless of current anesthetic depth

Answer 20

True

Question 21

what stage are most surgeries and intubation are performed at

Answer 21

stage 3, planes 2-3

Question 22

T/F adverse behavioral effects during stages 1-2 before and after anesthesia are treated with sedatives

Answer 22

True

Question 23

what can be seen with ketamine

Answer 23

nystagmus, blinking, central eye position and dilated pupils

Question 24

goals of anesthetic depth

Answer 24

acceptable cardiovascular function

fully relaxed and immobile patient

least necessary anesthetic depth

Question 25

T/F central eye + fixed pupils may indicate both too light or too deep anesthesia

Answer 25

True

Question 26

nystagmus

Answer 26

most likely indicate too light anesthesia

may happen with ketamine even at appropriate depth

Question 27

if spontaneous RR is high (>20 br/min) it may indicate

Answer 27

too light anesthesia

low lung volume or tidal volume

Question 28

T/F absolute HR does not aid determining anesthetic depth

Answer 28

True

Question 29

common causes of increased HR

Answer 29

surgical stimulus (nociception)

life threatening stress (hypoxemia)

anemia, hypovolemia, shock, hyperthermia

Question 30

common cause of decreased HR

Answer 30

drugs (opioids, alpha 2 agonists)

hypothermia