CONTINUOUS INFUSIONS OF ALFENTANIL AND PROPOFOL FOR CORONARY-ARTERY SURGERY

Objective: To study the anesthetic efficacy of two different backgroun d infusion rates for alfentanil in a total intravenous anesthesia (TIV A) technique using propofol. Therefore, the effects of these infusions on hemodynamic stability and on the suppression of hemodynamic and so matic responses to noxious stimuli were compared. Design: Prospective and randomized. Setting: The study was performed in a university hospi tal setting. Two patient groups were compared. Interventions: Anesthes ia was induced in group 1 (n = 16) with alfentanil 50 mu g/kg and in g roup 2 (n = 14) with alfentanil 75 mu g/kg, infused in 4 min, as well as with an infusion of propofol at a rate of 10 mg/kg/h in both groups . After 4 min, the alfentanil infusion was reduced to 1 mu g/kg/min in group 1 and to 2 mu g/kg/min in group 2. The propofol infusion was re duced following sternal spread to 3 mg/kg/h. Responses indicating inad equate anesthesia were treated with additional alfentanil bolus doses. Measurements and Main Results: Induction of anesthesia ingroup 1 was associated with significant decreases systolic and diastolic (-13%) bl ood pressures, cardiac index (-16%) and left ventricular stroke work i ndex (-31%). Hemodynamic changes were similar in group 2, except for t he greater fall in systemic vascular resistance during maintenance of anesthesia. There was no difference in the incidence of breakthrough h ypertension between the two groups (in 44% and 43% of the patients, re spectively) and in the number of alfentanil bolus supplements. There w ere also no differences in the incidence of ischemia, myocardial infar ction or duration of postoperative ventilation. Conclusions: Because b oth infusions provided equally stable anesthesia, the lower infusion r egimen for alfentanil is the more appropriate technique. Using this te chnique, the administration of additional alfentanil boluses just befo re stressful surgical episodes will further improve hemodynamic stabil ity. Copyright (C) 1995 by W.B. Saunders Company