This study evaluated the effects of remifentanil on hemodynamic changes in endotracheal intubation during rapid sequence induction using thiopental or propofol and succinylcholine.

One hundred and twenty patients were divided into 4 groups (30 patients in each group). Anesthesia was induced with propofol 2 mg/kg or thiopental 5 mg/kg and succinylcholine 1 mg/kg followed by remifetanil 0.5 µg/kg (group PR), remifentanil 1 µg/kg (group TR) or normal saline as control (group PC, group TC). An endotracheal intubation was performed 90 s later, and vecuronium 0.08 mg/kg was given for neuromuscular block. Anesthesia was maintained using 1-3 vol% enflurane with 2 L/min N₂O and 2 L/min O₂. Arterial blood pressure (ABP) and heart rate (HR) were recorded before induction, just before intubation, and at 1 min intervals for 5 min after intubation. The incidence of hypertension, hypotension, tachycardia, and bradycardia were recorded.

ABP in group PR was lower than in group TR, but HR was not different. The incidence of hypotension in group PR was higher than group TR or group PC. ABP in groups using remifentanil was lower than in control groups. The incidence of hypertension and tachycardia in groups using remifentanil were lower than control groups.

During administration of propofol or thiopental and succinylcholine, remifentanil as a bolus for rapid sequence induction attenuated cardiovascular responses to endotracheal intubation effectively, but with a higher incidence of hypotension following propofol.