Purpose: Administration of remifentanil followed by propofol provides adequate conditions for tracheal intubation without muscle relaxants. Other hypnotic drugs have not been thoroughly investigated in this regard. Intubating conditions with remifentanil followed by propofol, thiopentone or etomidate are compared in this study.
Methods: In a randomized, double-blind study 45 healthy males were assigned to one of three groups (n = 15). After iv atropine, remifentanil 3 microg x kg(-1) were injected over 90 sec followed by propofol 2 mg x kg(-1) (Group I), thiopentone 6 mg x kg(-1) (Group II) or etomidate 0.3 mg x kg(-1) (Group III). Ninety seconds after the administration of the hypnotic agent, laryngoscopy and intubation were attempted. Intubating conditions were assessed as excellent, good or poor on the basis of ease of ventilation, jaw relaxation, position of the vocal cords, and patient response to intubation and slow inflation of the endotracheal tube cuff.
Results: One patient in Group I, three patients in Group II and five patients in Group III could not be intubated on the first attempt. Clinically acceptable intubating conditions were observed in 93.3%, 66.7%, 40.0% of patients in Groups I, II and III, respectively. Overall conditions at intubation were significantly (P < 0.05) better, and the frequency of excellent conditions was significantly (P < 0.05) higher in the propofol group compared with the thiopentone and etomidate groups. No patient was treated for hypotension or bradycardia.
Conclusion: Propofol 2 mg x kg(-1) was superior to thiopentone 6 mg x kg(-1) and etomidate 0.3 mg x kg(-1) for tracheal intubation when combined with remifentanil 3 microg x kg(-1) and no muscle relaxant.