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 rebreathing method.Fentanyl 1 [micro sign]g/kg was given to women undergoing 10- to 20-min procedures. Anesthesia was induced (n = 20 each) with one of the following: 1) sevoflurane and N2 O from a rebreathing bag (Sevo/Bag). A 5-L bag was prefilled with a mixture of sevoflurane 7% and N2 O 60% in oxygen. The bag was connected between the normal circle system, separated by a spring-loaded valve; 2) sevoflurane 8% and N (2) O 60% from a circle system on a conventional 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. Induction times were comparable with each method. Recovery duration was shortest with sevoflurane, intermediate with propofol, and longest with thiopental. Induction drug costs were lowest with Sevo/Bag and thiopental, intermediate with Sevo/Circle, and highest with propofol. However, sevoflurane (by either method) caused considerable nausea and vomiting that required treatment. Consequently, total drug cost was least with thiopental, intermediate with Sevo/Bag and propofol, and greatest with Sevo/Circle. Thus, no single technique was clearly superior. Implications: Anesthetic induction techniques influence awakening time, recovery duration, and drug costs. We tested two IV methods and two inhaled techniques. However, none of the four tested methods was clearly superior to the others. (Anesth Analg 1999;88:930-5)