[Etomidate versus propofol for anesthesia in ambulatory cardioversion].

OBJECTIVE: This study compared the two short-acting intravenous anaesthetic agents, etomidate in lipid emulsion and propofol, for anaesthesia during elective outpatient cardioversion.

METHODS: After institutional approval and informed consent, 40 patients (ASA II/III) scheduled for cardioversion were studied. Patients with a left ventricular ejection fraction < 30% were excluded. The anti-arrhythmic medication was not discontinued, and no patient was given pharmacological premedication. Anaesthesia was induced either with etomidate (in lipid emulsion) 0.25 mg/kg or propofol 1.5 mg/kg. Both agents were administered over 30 seconds. Subsequent increments were given until the patients no longer followed verbal commands and the lid reflex was absent. Patients were allowed to breathe 40% oxygen via face mask. Artificial ventilation was performed if a patient became apnoeic for more than 20 seconds. The blood pressure was monitored continuously with the Finapres noninvasive blood pressure monitor, and the heart rate was recorded simultaneously. All data were collected electronically. The duration of anaesthesia was taken as the period from the start of induction until the opening of the eyes on command. For assessment of recovery from anaesthesia, patients were asked to perform a series of psychomotor tests.

RESULTS: The two groups were similar in their demographic and haemodynamic baseline data. In both groups, a significant decrease in blood pressure occurred 120 seconds after anaesthesia induction, which was due to the performance of the cardioversion. Five minutes after induction, the blood pressure returned to baseline in the etomidate group, while it remained below baseline in the propofol group. Propofol caused a significant decrease in heart rate. Significantly more patients needed artificial ventilation after propofol administration because of apnoea. Involuntary muscle movements occurred only in patients receiving etomidate. The immediate emergence from anaesthesia was faster after propofol. However, 15 minutes after awakening there was no difference in psychomotor skills between the two groups. No residual psychomotor impairment was evident 60 minutes after anaesthesia in any patient. All patients were discharged four hours after the cardioversion.

CONCLUSIONS: Because the recovery characteristics were similar in both groups, the occurrence of side effects may be a major factor when choosing between etomidate and propofol for outpatient cardioversion.