A comparison of propofol and thiopentone as induction agents in outpatient surgery.

We studied 90 healthy ASA physical status I or II female patients scheduled for outpatient therapeutic abortions. Sixty patients received induction doses of propofol (2.5 mg X kg-1) and 30 patients received thiopentone (4 mg X kg-1). Anaesthesia was maintained with nitrous oxide plus additional doses of the agent used for induction. Comparisons were made regarding the efficacy of induction and maintenance, rapidity of recovery, haemodynamic and respiratory variables and side effects. The number of "excellent" inductions was significantly different (p = 0.02), with 97 per cent of the patients induced with propofol and 80 per cent of the patients induced with thiopentone receiving this rating. A larger number of patients receiving propofol exhibited minor extraneous muscular movement during induction (p = 0.01). Recovery for the propofol group was significantly more rapid than with the thiopentone group (p = 0.001). The respiratory effect of the two drugs was not significantly different. Propofol caused a decrease in pulse rate and a decrease in systolic, diastolic and mean pressure which were significantly greater than with thiopentone. From the observations made we conclude that propofol has the potential to be an excellent induction and maintenance agent for outpatient surgery in combination with nitrous oxide alone.