Effect of ephedrine on the onset time of succinylcholine.

BACKGROUND

The aim of this study was to evaluate the effect of ephedrine administered prior to induction of anaesthesia on the onset time of succinylcholine for endotracheal intubation.

METHODS

Patients were randomly assigned to receive intravenously (i.v.) either 70 microg kg(-1) of ephedrine (Group I; n = 25) or saline (Group II; n = 25) 3 min before induction of anaesthesia. Induction of anaesthesia was provided with propofol 2 mg kg(-1) plus remifentanil 1 microg kg(-1). Onset time and duration of muscle fasciculation and onset time of succinylcholine were recorded. Intubation was attempted after establishment of 100% thumb relaxation and difficulties were recorded. Heart rate, pulse oxymetry (SpO2) and mean arterial pressure (MAP) were also recorded.

RESULTS

The onset time of succinylcholine were significantly (P < 0.001) shorter in Group I (26 +/- 4 s), when compared with Group II (43 +/- 6 s). Patients in Group I were intubated at 49 +/- 7 s compared with 68 +/- 10 s in Group II. The score of intubation was similar in both groups. Duration of muscle fasciculation was longer in Group II. Heart rate and MAP increased significantly (P < 0.05) after ephedrine injection, compared with the baseline value in Group I.

CONCLUSIONS

The onset time of succinylcholine can be shortened with ephedrine pretreatment.