INHALED ANESTHETICS

Question 1

· Nitrous Oxide

Answer 1

o MAC (dose): 104% (won’t solely induce pt, used as 2nd gas effect)
o Blood:Gas Partition Coefficient (onset): 0.46
o Vapor Pressure: 38,770 torr (745 psi)
o ½ Life: dependent on CO and Vm
o Elimination: alveoli (1), hepatic biotransformation (2), and percutaneous loss (3)
o Action: SVR +, HR +, CVP +, SV no change
o C/I: Bowel sx, pneumothorax, intraocular sx s/p retinal repair, inner ear sx, bullae in cxr, pregnant pts (B12 deficiency), neuro case (not neuroprotective, increases CMRO2 and CBF), Pulm HTN (causes further myocardial depression with inc pulm vessel resistance),

Question 2

· Isoflurane (used solely for ICU patients that will stay intubated)

Answer 2

o MAC (dose): 1.2% (most potent)
o Blood:Gas Partition Coefficient (onset): 1.46 (most soluble in blood = slowest onset)
o ½ Life: dependent on CO and Vm
o Elimination: alveoli (1), hepatic biotransformation (2), and percutaneous loss (3)
o Action: SVR -, HR +, CVP +, SV -, prolongation of QT interval
o When to use: When bronchodilation is needed (Asthma attack)
o C/I: Dont use to induce pt d/t pungent smell
o Precautions: Dehydrated soda lima will interact to produce Carbon Monoxide

Question 3

· Sevoflurane

Answer 3

o MAC (dose): 1.8%
o Blood:Gas Partition Coefficient (onset): 0.69
o ½ Life: dependent on CO and Vm
o Elimination: alveoli (1), hepatic biotransformation (2), and percutaneous loss (3)
o Action: SVR - (the least!), HR no change, CVP no change, SV -, prolongation of QT interval
o When to use: Neuro case (least vasodilatory effect), bronchodilation in asthma attack, to initiate induction
o Precautions: Dehydrated soda lima will interact to produce Compound A

Question 4

· Desflurane (Not used much in anesthesia anymore)

Answer 4

o MAC (dose): 6.6%
o Blood:Gas Partition Coefficient (onset): 0.42 (least soluble in blood = fast onset)
o ½ Life: dependent on CO and Vm
o Elimination: alveoli 99.82%… (1), hepatic biotransformation 0.02% (2), and percutaneous loss ~0% (3)
o Action: SVR -, HR ++, CVP +, SV -, prolongation of QT interval
o C/I: Avoid with airway diseases d/t increase reactivity/irritation of airway, don’t use to induce pt; Dehydrated soda lima will interact to produce Carbon Monoxide
o Precautions: Will increase both BP and HR with overpressurization.

Question 5

CO2 MAC

Answer 5

200