The effects of sevoflurane with propofol and remifentanil on tracheal intubation conditions without neuromuscular blocking agents

Background: Propofol and remifentanil are used for tracheal intubation in the absence of neuromuscular blocking agents. We hypothesized that the addition of sevoflurane to propofol and remifentanil would improve intubation conditions and provide hemodynamic stability. Methods: Seventy-six patients scheduled for elective surgery were randomly allocated to be ventilated with either 4% (group I) or 7% sevoflurane (group II) after propofol injection (2 mg/kg). All patients received remifentanil (1 mu g/kg) 30 seconds after administration of propofol. Ninety seconds after remifentanil was given, laryngoscopy and tracheal intubation were performed. Intubation conditions and hemodynamic changes were evaluated. Results: The overall incidence of clinically acceptable intubation conditions was significantly higher in group II (92%) than group I (58%) (P = 0.001). Scores for vocal cord position, coughing, and limb movement were significantly better in group II (P < 0.05). Mean blood pressure remained significantly lower than the pre-induction level throughout the investigation in both groups (P < 0.001), but there was no incidence of bradycardia or hypotension requiring treatment. Conclusions: Tracheal intubation without neuromuscular blocking agents can be achieved safely and reliably by adding 7% sevoflurane to propofol (2 mg/kg) and remifentanil (1 mu g/kg).