So I'm doing some practice questions to prepare to written boards next week (yikes!) and I must admit I'm stumped by this question. A decrease in cardiac output will have the LEAST impact on the rate of change to the FA/FI ratio for which volatile agent? Options are like sevo, iso, des, nitrous.
I would have picked nitrous oxide. Least soluble, least effect of cardiac output on FA/FI since very little is taken up anyway. The printed answer is isoflurane and the explanation says it's because it has the largest blood-gas partition coefficient, is the least soluble, and therefore would have least impact of FA/FI during states of decreased cardiac output. Huh? I really thought I understood this until now!
I would have picked nitrous oxide. Least soluble, least effect of cardiac output on FA/FI since very little is taken up anyway. The printed answer is isoflurane and the explanation says it's because it has the largest blood-gas partition coefficient, is the least soluble, and therefore would have least impact of FA/FI during states of decreased cardiac output. Huh? I really thought I understood this until now!