The effect of ephedrine on the onset time of rocuronium in Thai patients

Abstract

The aim of this study was to determine the effect of ephedrine on the onset time of rocuronium. The study population was 60 ASA physical status 1 and 2 patients, aged 15-60 years scheduled for elective surgery under general anesthesia at Ramathibodi Hospital. The patients were randomly assigned into 2 groups. Group I (ephedrine group), ephedrine 70 μg/kg was given 1 minute before induction and group II (control group), saline was given instead of ephedrine and midazolam 7.5 mg was given orally 30-60 minutes before the induction. Anesthesia was induced with fentanyl 1 μg/kg and sodium thiopentone 3-5 mg/kg. The patient was intubated with 0.9 mg/kg of rocuronium. The intubation time (from rocuronium administration to the time of intubation) was predetermined by the Dixon's up and down method (with 5 seconds as a step size) for each patient and started at 60 seconds for the first patient in each group. The intubation time in the ephedrine group (39.41 ± 4.64 seconds) was significantly different from the control group (59.17 ± 9.00 seconds); p-value < 0.01. The hemodynamics were similar in both groups. Conclusion: Intravenous ephedrine shortened the onset time of rocuronium with no significant adverse hemodynamic effects. As an alternative to suxamethonium for rapid intubation, the authors recommend the use of ephedrine 70 μg/kg at one minute before induction followed by 0.9 mg/kg of rocuronium intravenously in healthy patients. The intubation could be achieved at 40 seconds after the administration.