Onset time, recovery duration, and drug cost with four different methods of inducing general anesthesia

We compared two conventional induction techniques (thiopental and propofol) , an inhaled induction with sevoflurane using a circle system, and a rebrea thing method. Fentanyl 1 mu g/kg was given to women undergoing 10- to 20-mi n procedures. Anesthesia was induced (n = 20 each) with one of the followin g: 1) sevoflurane and N2O from a rebreathing bag (Sevo/Bag). A 5-L, bag was prefilled with a mixture of sevoflurane 7% and N2O 60% in oxygen. The bag was connected between the normal circle system, separated by a spring-loade d valve; 2) sevoflurane 8% and N2O 60% from a circle system on a convention al anesthesia machine with a total fresh gas flow of 6 L/min (Sevo/Circle); 3) propofol 3 mg/kg as an IV bolus; 4) thiopental sodium 5 mg/kg as an IV bolus. Postoperative nausea and vomiting was treated with ondansetron. Indu ction times were comparable with each method. Recovery duration was shortes t with sevoflurane, intermediate with propofol, and longest with thiopental . Induction drug costs were lowest with Sevo/Bag and thiopental, intermedia te with Sevo/Circle, and highest with propofol. However, sevoflurane (by ei ther method) caused considerable nausea and vomiting that required treatmen t. Consequently, total drug cost was least with thiopental, intermediate wi th Sevo/Bag and propofol, and greatest with Sevo/Circle. Thus, no single te chnique was clearly superior. Implications: Anesthetic induction techniques influence awakening time, recovery duration, and drug costs. We tested two TV methods and two inhaled techniques. However, none of the four tested me thods was clearly superior to the others.