Background and Goal of Study: Rapid tracheal intubation may be accomplished with a large dose of rocuronium but the prolonged duration of action is a problem.
Successful tracheal intubation without muscle relaxant is reported with remifentanil 3-4 μg/kg but hypotension is a problem. We tried to find adequate dose of rocuronium for rapid tracheal intubation with combined use of induction dose of propofol and remifentanil.
Materials and Methods: ASA physical status I - II adult patients aged 18-65 yr were enrolled. After premedication with midazolam and glycopyrrolate, patients were induced with remifentanil 2 μg/kg, propofol 2 mg/kg, and predetermined dose of rocuronium.
Intubation was done at 60 s from the start of rocuronium injection. Intubation conditions were graded as excellent, good, poor and excellent or good level was regarded as clinically acceptable. The dose of rocuronium was determined by Dixon's up-and-down method. The first patient received 0.8 mg/kg of rocuronium. Heart rate and blood pressure (SAP, MAP, DAP) were recorded before induction, 30 s after propofol injection, and 1, 2, and 3 min after tracheal intubation.
Results and Discussion: The rocuronium dose for acceptable intubation conditions was 0.20 (0.05) mg/kg. ED50 and ED95 from probit analysis were 0.20 (95% CI: 0.14-0.25) mg/kg and 0.29 (95% CI: 0.24-0.62) mg/kg respectively.
Heart rate and blood pressure decreased significantly after propofol injection but no significant changes thereafter.
Conclusion(s): When combined with remifentanil 2 μg/kg and propofol 2 mg/kg, the rocuronium dose needed for acceptable intubation condition in 95% of patients was 0.3 mg/kg.