Inhalational anesthetics

Question 1

What does the depth of general anesthesia depend on?

Answer 1

The partial pressure/gas fraction exerted by the agent on the brain

Question 2

What is the steady state in inhalational anesthetics?

Answer 2

Equal partial pressures in the 2 phases

Question 3

What is the partition coefficient?

Answer 3

Ratio of the concentrations of the vapor in each of the 2 phases AT STEADY STATE

Question 4

Oil:Gas coefficient is related to:

Answer 4

Lipid solubility and potency

Question 5

What is the most important factor in MAC?

Answer 5

Partial pressure of gas in the alveolus which will equilibrate with concentration in the brain

Question 6

What is MAC?

Answer 6

Minimum alveolar concentration of inhalational drug that prevents movement in 50% of patients in response to surgical stimulation

Question 7

What is MAC equivalent to?

Answer 7

ED50

Question 8

MAC provides a standard way of estimating:

Answer 8

1) Anesthetic depth
2) Comparisons between agents

Question 9

MAC values are __ between different inhalational agents.

a) Synergistic
b) Additive
c) Potentiative

Answer 9

b) Additive

Question 10

MAC is __ (directly/inversely) proportional to:

Answer 10

Inversely; potency (lipid solubility)

Question 11

A MAC of 0.3-0.4 means:

Answer 11

MAC-awake: Awakening from anesthesia in absence of other agents

Question 12

A MAC of 1.3 means:

Answer 12

ED95: Blunting of response in 95% of patients

Question 13

A MAC of 1.5 means:

Answer 13

MACBAR: Blocking of adrenergic response to surgical stimulation

Question 14

What is the most significant cardiovascular effect of Isoflurane?

Answer 14

Reduction of TPR (SVR) = Decrease BP

Question 15

Why is Isoflurane not used for induction?

Answer 15

Because of the pungent smell

Question 16

What is Isoflurane?

Answer 16

A haloginated methyl ethyl ether

Question 17

What are 2 side effects of Isoflurane? (1 CNS and 1 RS)

Answer 17

1) Increases ICP at&raquo_space; 1 MAC
2) Irritates upper airway reflex

Question 18

What is Isoflurane’s MAC?

Answer 18

1.2%

Question 19

What is Sevoflurane?

Answer 19

A fluorinated methyl isopropyl ether

Question 20

What is the most commonly used inhalational drug for induction and why?

Answer 20

Sevoflurane; It’s non-pungent and has a low MAC

Question 21

What is Sevoflurane’s MAC?

Answer 21

2%

Question 22

What is a CVS side effect of Sevoflurane?

Answer 22

Low arterial BP

Question 23

Which inhalational agent provides adequate muscle relaxation for intubation of children?

Answer 23

Sevoflurane

Question 24

What degrades Sevoflurane?

Answer 24

Alkali (Soda lime, barium hydroxide)

Question 25

What compounds does Sevoflurane produce after degradation?

Answer 25

Nephrotoxic end products (compound A)

Question 26

What is Desflurane?

Answer 26

A Halogenated ether

Question 27

Why does Desflurane require a special vaporizer?

Answer 27

Because it has a high Saturated Vapor Pressure (SVP)

Question 28

Desflurane has a __(high/low) solubility, which means it has __(rapid/slow) onset and offset.

Answer 28

Low; rapid

Question 29

What is Desflurane’s MAC?

Answer 29

6%

Question 30

Desflurane is degraded by __ into:

Answer 30

Dessicated CO2 absorbent; carbon monoxide