Inhaled anesthetics 2: Pharmacodynamics 3

Question 1

Sevoflurane at 1.5 MAC increases:
a. cerebral metabolic rate of oxygen
b. cerebral blood volume
c. cerebral vascular resistance
d. cerebrospinal fluid production

Answer 1

b. cerebral blood volume (volatile anesthetics supply the brain with more blood flow than it needs)

Question 2

What level of MAC is required to produce an isoelectric state?

Answer 2

1.5-2.0 MAC

Question 3

How do halogenated anesthetics impact CMRO2?

Answer 3

dose-dependent reduction in CMRO2

Question 4

How do halogenated agents impact cerebral blood flow?

Answer 4

dose-dependent increase in CBF

Question 5

How do halogenated agents impact cerebral blood volume?

Answer 5

dose-dependent increase

Question 6

How do halogenated agents impact ICP?

Answer 6

dose-dependent increase

Question 7

___________ in high concentrations (2.0) MAC can produce seizure activity.

Answer 7

Sevoflurane

Question 8

Sevoflurane’s ability to produce seizure activity in high concentrations is exacerbated by

Answer 8

hypocapnia & is more common with inhalation induction

Question 9

How does nitrous oxide impact CMRO2?

Answer 9

increases CMRO2

Question 10

How does nitrous oxide impact cerebral blood flow?

Answer 10

increases CBF

Question 11

Which volatile anesthetic increases CSF production?

Answer 11

desflurane

Question 12

CMRO2 is dependent on:

Answer 12

electrical activity (60% of total brain oxygen consumption)
cellular homeostasis (40% of total brain oxygen consumption)

Question 13

What impact do volatile anesthetics have on cerebral vascular resistance?

Answer 13

cerebral vasodilators (they decrease CVR)

Question 14

Desflurane affects somatosensory evoked potentials by:
a. increasing amplitude and increasing latency
b. increasing amplitude and decreasing latency
c. decreasing amplitude and increasing latency
d. decreasing amplitude and decreasing latency

Answer 14

c. decreasing amplitude and increasing latency

Question 15

_______ are most resistant to the effects of anesthetics

Answer 15

brain auditory evoked potentials

Question 16

________ are the most sensitive to the effects of anesthetic agents

Answer 16

visual evoked potentials

Question 17

When using a volatile agent with evoked potentials, it is recommend to use

Answer 17

<0.5 MAC; you can supplement with IV agents (propofol, opioids) but don’t use N2O

Question 18

The best anesthetic technique to preserve evoked potentials is

Answer 18

TIVA without N2O

Question 19

Volatile anesthetics impair evoked potential monitors by

Answer 19

decreasing the amplitude and increasing the latency of the signal

Question 20

As a general rule, you should be concerned about nerve ischemia when amplitude ____________ or latency __________

Answer 20

amplitude decreases by >50% or latency increases by >10%

Question 21

______ monitor the integrity of the dorsal column (medial lemniscus)

Answer 21

SSEPS

Question 22

SSEPs monitor the ___________ spinal artery(ies).

Answer 22

posterior

Question 23

_________ monitor the integrity of the corticospinal tract.

Answer 23

MEPs

Question 24

MEPs monitor the _____spinal artery (ies).

Answer 24

anterior

Question 25

Amplitude refers to

Answer 25

the strength of the nerve response

Question 26

Latency refers to the

Answer 26

speed of nerve conduction

Question 27

Anesthetic goals when evoked potential signals diminish or go away during surgery include

Answer 27

improving neural tissue perfusion by increasing BP, volume expansion, and transfusion (if anemic),