Inhaled Anesthetics - Agents

Question 1

Halothane Class, MAC, VP, B/G

Answer 1

halogenated alkane
0.75%
243 mmHg
B/G 2.3 - most soluble

Question 2

Halothane Considerations

Answer 2

10-20% is metabolized
NOT an airway irritant
Needs thymol preservative - decomposes in light
Sensitizes heart to catecholamines - most myocardial depressant
Toxic halothane hepatitis
Avoid above 1.5ugm/kg

Question 3

Isoflurane - class, MAC, VP, B/G

Answer 3

halogenated methyl ethyl ether
240 mmHG
1.2%
B/G: 1.4

Question 4

Isoflurane considerations

Answer 4

non-degraded, non-flammable, airway irritant

Question 5

Enflurane - class, MAC, VP, B/G

Answer 5

halogenated methyl ethyl ether
172mmHg
1.68%
B/G 1.8

Question 6

Enflurane considerations

Answer 6

isomer of isoflurane
risk of seizure activity
2-4% metabolized

Question 7

Desflurane

Answer 7

Fluorinated methyl ethyl ether
680mmHg
4-6%
B/G: 0.42

Question 8

Desflurane Considerations

Answer 8

lowest boiling pt - requires special vaporizer - TEC 6 heats to 39 and 2 ATM
low tissue solubility 
airway irritant
tachycardia 
long degradation in atmosphere
poor induction agent

Question 9

Sevoflurane -class, MAC, VP, B/G

Answer 9

Fluorinated isopropyl ether
160mmHg
2%
B/G: 0.65

Question 10

Nitrous Oxide - class, MAC, VP, B/G

Answer 10

inorganic
39,000mmHg
105% - not a complete anesthetic
B/G: 0.47

Question 11

Sevoflurane Considerations

Answer 11

best inhalation agent
NOT an airway irritant
rapid onset and recovery

Question 12

N2O Considerations

Answer 12

• Hypoxia risk with increased conc or decreased ATM
• 30-34x more soluble than nitrogen can cause closed air spaces to expand by replacing N2. CONTRAINDICATED in any case with risk of air embolus
• Critical temp 36.5 : the agent CANNOT exist as a liquid at ANY pressure

Question 13

Xenon

Answer 13

inert gas - nonreactive 
62-70%
B/G 0.115
expensive
little hemodynamic effects

Question 14

MAC

Answer 14

measures potency of anesthetic
1 MAC = prevents movement to painful stimuli in 50% of patients
1.3 MAC prevents in 95% of patients
decreases 6% per decade