Dexmedetomidine reduces pain associated with rocuronium injection without causing a decrease in BIS values: a dose-response study

Abstract

Study objectives: To examine whether dexmedetomidine reduces the injection pain of propofol and rocuronium and to investigate whether the decrease in injection pain is associated with the known sedative action of dexmedetomidine.

Design: Randomized, double-blind, placebo-controlled clinical comparison study.

Interventions: Patients undergoing general anesthesia with intubation received 40 mg of 1% lidocaine (lidocaine group; n = 28), 0.25 μg/kg of dexmedetomidine (low-dose group; n = 27), 0.5 μg/kg of dexmedetomidine (subclinical dose group; n = 28), 1.0 μg/kg of dexmedetomidine (clinical dose group, n = 27), or normal saline (saline group; n = 28) before anesthetic induction.

Measurements: Pain associated with propofol and rocuronium injection was assessed using a 10-point verbal analog scale (VAS) and a 4-point withdrawal movement scale, respectively. The BIS value was measured 60 seconds after administration of the study drug, and at the time of rocuronium injection and intubation.

Main results: The overall incidence of withdrawal movements due to rocuronium decreased significantly as the dose of dexmedetomidine increased (92.8%, 85.2%, 78.6%, and 51.9% in the saline, low-dose, subclinical dose, and clinical dose groups, respectively; P = 0.001). There was no significant difference in BIS values among the groups 60 seconds after study drug administration or at the time of rocuronium injection.

Conclusions: Dexmedetomidine reduced pain associated with rocuronium injection in a dose-dependent manner. This effect was not associated with the decrease in BIS value.

Keywords: Bispectral index; Dexmedetomidine; Injection pain; Propofol; Rocuronium.