Remifentanil-propofol combination is used to minimize the cardiovascular responses during anesthetic induction; however, it may generate side effects such as hypotension or bradycardia. The authors investigated the changes of stroke volume and cardiac output using impedance cardiography (ICG) when hypotension or bradycardia is generated during propofol-remifentanil anesthetic induction.

Ninety ASA physical status class I patients who were scheduled to undergo elective ambulatory surgery were randomly assigned to one of three groups (n = 30 each). Normal saline (Group S), remifentanil 0.25µg/kg/min (Group R0.25), or remifentanil 0.5 µg/kg/min (Group R0.5) was infused intravenously. Propofol was slowly administered two minutes after the administration of remifentanil or normal saline. Heart rate, mean arterial pressure, cardiac output and stroke volume were measured at preinduction (baseline), preintubation and postintubation.

Mean arterial pressure in Group R0.5 at preintubation decreased compared to that of the baseline, however, the stroke volume index was sustained. The stroke volume index at postintubation decreased proportionally as heart rate increased in heart rate in all groups, and then cardiac index was preserved.

Hypotension was generated during induction of anesthesia when remifentanil 0.5 µg/kg/min and propofol 1.0 mg/kg were used, however, the stroke volume index was sustained.