Desflurane affects somatosensory evoked potentials by:

Study on!!!
Evoked potentials are used to ----- the integrity of a neural pathway
"monitor"
What are the four types of evoked potentials
-
Somatosensory (SSEP)
-
Motor (MEP)
-
Visual (VEP)
-
Brainstem auditory (BAEP)
Evoked potentials are produced by applying ----- to a neural pathway
"current"
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.
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
Which types of evoked potentials monitor the integrity of the dorsal column (medial lemniscus)?
SSEPs
SSEPs monitor the integrity of the dorsal column (medial lemniscus). This region of the cord is perfused by the ------ spinal arteries
Posterior spinal arteries
Which types of evoked potentials monitor the integrity of the corticospinal tract?
MEPs
MEPs monitor the integrity of the corticospinal tract. This region of the cord is perfused by the ----- spinal artery
Anterior spinal artery
SSEPs do not monitor the Anterior cord
True
SSEPs do not monitor the Anterior cord and therefore aren't interchangeable with MEPs
True
Which two components of the evoked potential waveform are we most concerned with?
Amplitude and Latency

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

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

Losing the evoked potential signal (or recording a diminished response) suggests ----- to the neural pathway being monitored
ischemia
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"
As a general rule, you should be concerned about nerve ischemia when amplitude decreases by >/= --- percent
50 percent
As a general rule, you should be concerned about nerve ischemia when amplitude decreases by >/= 50 percent or latency increases by /= --- percent
10 percent
Volatile anesthetics ----- amplitude
"decrease"

Volatile anesthetics decrease amplitude and ----- latency
"increase"

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

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
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
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
The best anesthetic technique to preserve evoked potentials is ----- without N2O
TIVA
The best anesthetic technique to preserve evoked potentials is TIVA without N2O. Some institutions only use TIVA when evoked potentials are monitored
True
If you use a volatile agent, it's recommended that you use --- MAC or less
0.5 MAC
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
Muscle relaxants should not be used when which type of evoked potentials are monitored?
MEPs
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
Which IV induction agent enhances the evoked potentials signal?
Ketamine
Which type of evoked potentials are most resistant to the effects of anesthetics
Brainstem auditory (BAEPs)
Brainstem auditory evoked potentials (BAEPs) are most resistant to the effects of anesthetics, and thus any anesthetic technique may be used
True
Which type of evoked potentials is the most sensitive to the effects of anesthetic agents, and thus are seldom used?
Visual evoke (VEP)
If the evoked potential signal diminishes or goes away during surgery, the surgeon should investigate a ----- cause
Mechanical cause
(such as surgical distraction)
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
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
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
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
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
Desflurane affects somatosensory evoked potentials by:

Decreasing amplitude and increasing latency
[Volatile agents decrease amplitude and increase latency of SSEPs.]
References:
Barash. Clinical Anesthesia. 8th ed. 2017. p. 1009-1011. Nagelhout. Nurse Anesthesia. 6th ed. 2018. p. 84.