Inhalation Anesthetics Flashcards
T/F: Soluble drugs take longer to reach steady state then insoluble drugs
True:
A soluble drug has a longer induction and recovery, large Vd, and is more potent, while insoluble anesthetics have a fast induction and recovery (if completely insoluble they will not get into the brain)
Two important physiologic factors for inhalation anesthetics
Ventilation and cardiac output
T/F: All inhalation anesthetics are fat soluble, penetrate most tissues, but do not cross the placenta
False:
They do cross the placenta
What is MAC?
Minimum Alveolar Concentration - at steady state it will prevent purposeful movement in response to supra maximal noxious stimulus in 50% of individuals (ED50)
~1.3 MAC for maintenance
Second gas effect
Large proportion of gas volume moves from higher to lower tension (alveolus –> blood) to equilibrium
Nitrous oxide = more fresh gas to alveolus
Fink effect
Nitrous oxide from blood to alveolus displaces alveolar gas (including O2)
Give 100% O2 on recovery
Which inhalation anesthetics are considered vapors?
Halothane
Isoflurane
Desflurane
Sevoflurane
Which inhalation anesthetics are considered gases?
Nitrous oxide
Halothane effects on the liver
Decreased hepatic blood flow
60-80% eliminated in air
Isoflurane effects on the liver
Decreased hepatic blood flow but less than with Halothane
NOT metabolized in the liver (0.2%)
Desflurane effects on the liver
Decreased hepatic blood flow
NOT metabolized in the liver (0.2%)
Sevoflurane effects on the liver
Decreased hepatic blood flow
NOT metabolized
Nitrous oxide effects on the liver
Minimal effects
Respiratory/Cardiac effects of Halothane
Depression
MOST arrhythmogenic, sensitizes heart to Epinephrine
Respiratory/Cardiac effects of Isoflurane
LESS cardiac depression than Halothane
SAME respiratory depression as Halothane
