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Apex 4 - 5 Volatile Anesthetics II: Pharmacodynamics (11) > Evoked Potential Monitoring > Flashcards

Flashcards in Evoked Potential Monitoring Deck (43)
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1

Desflurane affects somatosensory evoked potentials by:

Study on!!!

2

Evoked potentials are used to ----- the integrity of a neural pathway

"monitor"

3

What are the four types of evoked potentials

 

 

  1. Somatosensory (SSEP)
  2. Motor (MEP)
  3. Visual (VEP)
  4. Brainstem auditory (BAEP)

4

Evoked potentials are produced by applying ----- to a neural pathway

 

"current"

5

Evoked potentials are produced by applying current to a neural pathway. For example, SSEPs are produced by applying current to a peripheral nerve - most commonly the ----- n. or ----- n.

Ulnar n. or Tibial n.

6

Evoked potentials are produced by applying current to a neural pathway. The electrical current travels from the peripheral nerve to the ----- side of the cerebral cortex.

Contralateral side

7

Which types of evoked potentials monitor the integrity of the dorsal column (medial lemniscus)?

SSEPs

8

SSEPs monitor the integrity of the dorsal column (medial lemniscus). This region of the cord is perfused by the ------ spinal arteries

Posterior spinal arteries

9

Which types of evoked potentials monitor the integrity of the corticospinal tract?

MEPs

10

MEPs monitor the integrity of the corticospinal tract. This region of the cord is perfused by the ----- spinal artery

Anterior spinal artery

11

SSEPs do not monitor the Anterior cord

True

12

SSEPs do not monitor the Anterior cord and therefore aren't interchangeable with MEPs

True

13

Which two components of the evoked potential waveform are we most concerned with?

Amplitude and Latency

14

The ---- of the evoked potential waveform represents the strength of the nerve response

Amplitude

15

The ---- of the evoked potential waveform represents the speed of nerve conduction

Latency

16

Losing the evoked potential signal (or recording a diminished response) suggests ----- to the neural pathway being monitored

ischemia

17

Losing the evoked potential signal (or recording a diminished response) suggests ischemia to the neural pathway being monitored. For this reason, it is imperative to administer an anesthetic that ----- with the evoked potential monitoring technique

"doesn't interfere"

18

As a general rule, you should be concerned about nerve ischemia when amplitude decreases by >/= --- percent

 

50 percent

19

As a general rule, you should be concerned about nerve ischemia when amplitude decreases by >/= 50 percent or latency increases by /= --- percent

10 percent

20

Volatile anesthetics ----- amplitude

 

 

"decrease"

21

Volatile anesthetics decrease amplitude and ----- latency

"increase"

22

Volatile anesthetics decrease amplitude and increase latency. The addition of N2O makes this -----.

"worse"

23

Volatile anesthetics decrease amplitude and increase latency. The addition of N2O makes this worse. Hypoxia is a confounding factor that affects amplitude and/or latency

 

True

24

Volatile anesthetics decrease amplitude and increase latency. The addition of N2O makes this worse. ----- is a confounding factor that affects amplitude and/or latency

A. Hypercarbia

B. Hypocarbia

 

Hypercarbia

25

Volatile anesthetics decrease amplitude and increase latency. The addition of N2O makes this worse. -----  is a confounding factor that affects amplitude and/or latency

A. Hyperthermia

B. Hypothermia

 

 

Hypothermia

26

The best anesthetic technique to preserve evoked potentials is ----- without N2O

TIVA

27

The best anesthetic technique to preserve evoked potentials is TIVA without N2O. Some institutions only use TIVA when evoked potentials are monitored

True

28

If you use a volatile agent, it's recommended that you use --- MAC or less

0.5 MAC

29

If you use a volatile agent, it's recommended that you use 0.5 MAC or less. You can supplement with intravenous agents (propofol, opioid), but do not use ----- as this combination can further impair the signal

N2O

30

Muscle relaxants should not be used when which type of evoked potentials are monitored?

MEPs

31

Muscle relaxants should not be used when MEPs are monitored, however, a ----- may be given during induction so long as it will be metabolized before evoked potentials are required

Short-acting NMB

32

Which IV induction agent enhances the evoked potentials signal?

Ketamine

33

Which type of evoked potentials are most resistant to the effects of anesthetics

Brainstem auditory (BAEPs)

34

Brainstem auditory evoked potentials (BAEPs) are most resistant to the effects of anesthetics, and thus any anesthetic technique may be used

True

35

Which type of evoked potentials is the most sensitive to the effects of anesthetic agents, and thus are seldom used?

Visual evoke (VEP)

36

If the evoked potential signal diminishes or goes away during surgery, the surgeon should investigate a ----- cause

 

Mechanical cause

(such as surgical distraction)

37

If the evoked potential signal diminishes or goes away during surgery, the surgeon should investigate a mechanical cause (such as surgical distraction). Anesthetic goals include improving neural tissue perfusion by increasing -----.

 

Blood Pressure

38

If the evoked potential signal diminishes or goes away during surgery, the surgeon should investigate a mechanical cause (such as surgical distraction). Anesthetic goals include improving neural tissue perfusion by increasing BP, ----- expansion
 

Volume expansion

39

If the evoked potential signal diminishes or goes away during surgery, the surgeon should investigate a mechanical cause (such as surgical distraction). Anesthetic goals include improving neural tissue perfusion by increasing BP, volume expansion, and ----- (if anemic)

Transfusion

40

If the evoked potential signal diminishes or goes away during surgery, the surgeon should investigate a mechanical cause (such as surgical distraction). Anesthetic goals include improving neural tissue perfusion by increasing BP, volume expansion, and transfusion (if anemic). Normalizing gas tensions may also help.

True

41

If the evoked potential signal diminishes or goes away during surgery, the surgeon should investigate a mechanical cause (such as surgical distraction). Anesthetic goals include improving neural tissue perfusion by increasing BP, volume expansion, and transfusion (if anemic). Normalizing gas tensions may also help.

Communication with the surgical team is essential.

True

42

Desflurane affects somatosensory evoked potentials by:

Decreasing amplitude and increasing latency

[Volatile agents decrease amplitude and increase latency of SSEPs.]

43

References:

 

Barash. Clinical Anesthesia. 8th ed. 2017. p. 1009-1011. Nagelhout. Nurse Anesthesia. 6th ed. 2018. p. 84.