The pharmacokinetic study of desflurane, sevoflurane, isoflurane and enflurane in general anesthesia

Objective: To compare pharmacokinetics of desflurane, sevoflurane, isoflurane and enflurane in general anesthesia.

Methods: 40 patients scheduled for abdominal hysterectomy under general anesthesia were randomly divided into desflurane(D), sevoflurane(S), isofluane(I) and enflurane(E) groups. After induction of anesthesia and endotracheal intubation, desired fraction (Fd) of desflurane(6%), sevoflurane(2%), isoflurane (1.15%) and enflurane(1.7%) in oxygen and nitrous oxide(1:2) were inhaled in D, S, I and E groups, respectively. The fractional end tidal alveolar concentration (Fa) was adjusted to 1MAC during the maintenance of anesthsia. Fa and the fractional inspired concentration of inhaled anesthetics (Fi) were monitored continuously. During operation, fentanyl was infused continuously and pancuronium was injected intermittently.

Results: After the beginning of inhalational anesthesia, the time required for Fa/Fi = 1:2 and Fa = 1MAC in D and S groups was significantly shorter than that in E and I groups. The rates of Fa/Fi in D and S groups were significantly higher than those in E and I groups during the maintenance of anesthesia, so were those of Fa/Fd. After cessation of inhalational anesthesia, the time required for Fa equaled to 50% of Fa0(the last Fa during stoping administration of the inhalational anesthesia) in D group was significantly faster than that in the other three groups.

Conclusions: The rates of desflurane wash-in and wash-out are faster than those of other inhaled anesthetics. The depth of anesthesia is easy to control when desflurane is used in general anesthesia.