Opioids are the most widely used drugs to minimize the increase of blood pressure and heart rate in endotracheal intubation during the induction of anesthesia. The purpose of this study was to compare the effects of fentanyl, alfentanil, and remifentanil on the cardiovascular response to laryngoscopic endotracheal intubation.

Eighty ASA I-II patients were randomly allocated to four groups. The patients received 10 ml intravenous saline (control group), 3 µg/kg fentanyl (fentanyl group), 10 µg/kg alfentanil (alfentanil group) or 0.5 µg/kg remifentanil followed by an infusion of 0.1 µg/kg/min remifentanil (remifentanil group). Anesthesia was induced with propofol and rocuronium and maintained with 2 vol% sevoflurane and 50% nitrous oxide in oxygen. The noninvasive blood pressure and heart rate were recorded before induction (baseline), after induction, before intubation, and at 1 min intervals until 5 min after endotracheal intubation.

Arterial pressure and heart rate after endotracheal intubation were lower in the fentanyl, alfentanil, and remifentanil groups than in the control group (P < 0.05). There were no significant differences for arterial pressure or heart rate in the fentanyl, alfentanil, and remifentanil groups at any time. There were no significant differences for the incidence of hypotension and bradycardia among the four groups.

Administration of 3 µg/kg fentanyl, 10 µg/kg alfentanil and 0.5 µg/kg remifentanil followed by an infusion of 0.1 µg/kg /min remifentanil have a similar effect in the suppression of the cardiovascular response to laryngoscopic endotracheal intubation during the induction of general anesthesia.