Inhalational Anesthetics Flashcards
1
Q
Blood/Gas Partition Coefficients:
- N2O
- Halothane
- Isoflurane
- Desflurane
- Sevoflurane
A
- N2O: 0.46
- Halothane: 2.4
- Isoflurane: 1.4
- Desflurane: 0.42
- Sevoflurane: 0.65
2
Q
MAC%:
- N2O
- Halothane
- Isoflurane
- Desflurane
- Sevoflurane
A
- N2O: 105%
- Halothane: 0.75%
- Isoflurane: 1.2%
- Desflurane: 6.0%
- Sevoflurane: 2.0%
3
Q
Effects of N2O
A
- Sympathetic nervous system stimulation–>small increase (or no change) in HR, MAP, and CO
- mild myocardial depression (outweighed by sympathetic stimulation)
- increased CBF, CBV–>mild increase in ICP
- increased CMRO2
- increased pulmonary vascular resistance
- does NOT potentiate muscle relaxation (like the halogenated volatiles)
- inhibits methionine synthetase (myelin formation) and thymidylate synthetase (DNA synthesis)
- prolonged exposure: peripheral neuropathy, pernicious anemia, megaloblastic anemia, and depressed bone marrow (through B12 effects- N2O oxidizes cobalt in B12)
4
Q
Degree of metabolism of sevo, iso, des, N2O, and halothane
A
Sevo: 5% Iso: 0.2% Des: 0.1% Halothane: 20% N2O: 0.004%
5
Q
Which gas produces coronary vasodilatation?
A
Isoflurane (unfounded concerns re: coronary steal)
6
Q
What MAC produces burst suppression?
What MAC produces electrical silence?
A
Burst suppression: 1.5 MAC
Electric silence: 2.0 MAC
7
Q
Gases that can cause transient increases in sympathetic tone with rapid increases in concentration
A
Desflurane and isoflurane
8
Q
Gas most associated with carboxyhemoglobinemia?
A
Desflurane
- usually w/desiccated CO2 absorbent (classic is barium hydroxide lime)
- usually w/low fresh gas flows
9
Q
Compound A
A
- produced from sevoflurane w/dessicated CO2 absorbent such as barium hydroxide lime (Baralyme) or soda lime (but NOT calcium hydroxide)
- recommendation: keep flows at 2 L/min or greater when using sevo for more than 2 hours
- Nephrotoxicity only shown in rats, not humans
