Abstract: Objective To determine the bolus dose of remifentanil required for reliable intubating condition when combined with propofol 2 mg/kg only.Methods 66 ASA Ⅰ～Ⅱpatients were randomly divided into 3 groups with 22 patients in each group.The predetermined dose of remifentanil for group 1,group 2,group 3 were 2,3,4 μg/kg respectively.All the patients were premedicate with midazolam 0.03 mg/kg.60 s after propofol 2 mg/kg and the predetermined dose of remifentanil were administered,laryngoscopy and intubation were performed and the intubating conditions were assessed.Results Clinically acceptable intubating conditions were observed in 11 patients in group 1 compared with that in 18 patients in group 2 and all in group 3(P<0.05).The significant but clinically acceptable reduction in mean arterial pressure(MAP) and heart rate(HR) after the administration of the drug were observed in each group(P<0.05).Conclusion Remifentanil 3⁴ μg/kg can reliably provide clinically acceptable intubating conditions when administered after propofol 2 mg/kg.

Key words: tracheal intubation, remifentanil, propofol