A comparison of propofol and etomidate for cardioversion

Bolus doses of propofol in patients for cardioversion often produce hypotension and apnea. Etomidate provides cardiovascular stability in these patients, but myoclonus may interfere with electrocardiographic interpretation. This study was designed to demonstrate whether propofol, when given as a low-dose infusion, can attain etomidate's hemodynamic stability without its attendant side effects. Forty consenting patients were randomly assigned to receive either propofol infusion (50 mg/min) for induction of anesthesia followed by a maintenance infusion (100 micrograms.kg-1.min-1) or etomidate (8 mg/min and 20 micrograms.kg-1.min-1). Calculation of loading infusion rates for propofol and etomidate resulted in averages of 0.64 mg.kg-1.min-1 (range, 0.39-1.04) and 0.09 mg.kg-1.min-1 (range, 0.05-0.14), respectively. Induction times (2.2 min) and the times from terminating drug administration to awake states (4.5 min) were similar for each group. Etomidate produced myoclonus in 45% of the patients; otherwise side effects were minimal, with no significant differences between groups. The means of systolic blood pressures in the etomidate group rose a maximum of 15.3 +/- 7.9% (95% confidence), while a modest decrease of 7.2 +/- 7.3% occurred with propofol. Administration of propofol by infusion for cardioversion retains all its beneficial qualities while attenuating its hypotensive effects, making it a suitable choice for these patients with cardiac arrhythmias.