Duration of apnoea with two different intubating doses of remifentanil

Abstract

We have studied the apnoea time after induction with two successful drug intubating regimes, both containing remifentanil. Group 1 (n=20); propofol 2 mg kg⁻¹ and remifentanil 2 μg kg⁻¹ and group 2 (n=20); propofol 2 mg kg⁻¹, remifentanil 1 μg kg⁻¹ and lignocaine 1 mg kg⁻¹. Intubation was possible in all 40 patients, and regarded as acceptable in 90% and 85% of patients, respectively. The median time to the return of spontaneous respiration was 487 s in group 1 and 270 s in group 2 (P < 0.05). Median end-tidal CO₂ concentration at the time of the first spontaneous respiration was 7.37 kPa in group 1 and 6.3 kPa in group 2 (P < 0.05). Both groups had a decrease in heart rate after induction, but this failed to reach either clinical or statistical significance, and no patient required atropine. Similarly, there was a decrease in arterial pressure after induction in both groups (P < 0.05), but this was not deemed to be clinically significant. Only two patients in each group required ephedrine 6 mg before arterial pressure was restored to within 25% of the base-line. Intubating conditions were similar in both groups, but group 2 provided a significantly shorter apnoea time.