[Tracheal intubation without muscle relaxants using propofol and varying doses of fentanyl]

This study was designed to evaluate airway and intubating conditions without muscle relaxants after administration of fentanyl and propofol in 55 patients aged 20-60 years for elective surgery. Patients were randomly assigned to one of four groups to receive fentanyl 0, 2, 3, or 4 micrograms.kg-1, respectively. Three minutes after the administration of fentanyl, propofol (2 mg.kg-1) was given for induction of anesthesia. After the loss of consciousness, laryngoscopy and tracheal intubation, supplemented with topical anesthesia of lidocaine (2 mg.kg-1), were attempted. In control group, without administration of fentanyl, all patients were judged to provide poor intubating conditions. Increasing doses of fentanyl reduced the incidences of movement and persistent coughing on laryngoscopy and intubation in a dose-related manner. However, visualization of the vocal cord was significantly. (P < 0.05) more likely to be impossible in patients in 4 micrograms.kg-1 fentanyl group (40%) compared with patients in 2 micrograms.kg-1 fentanyl group (7%). There were no significant differences among groups receiving fentanyl with respect to vocal cord position. The vocal cords were closed in 26% of patients receiving fentanyl and propofol for intubation. Tracheal intubation without muscle relaxants is not recommended because of the potential unacceptable intubating conditions.