Purpose: The purpose of this study was to determine the intubation time needed to facilitate tracheal intubation (Time(EI)) with a low dose of rocuronium (0.3 mg/kg) during propofol induction, and to determine whether this time was reduced by the administration of atropine.
Methods: Forty-six children, aged 3-10 years, were randomly assigned to receive either saline (control group) or atropine 10 μg/kg (atropine group). Anesthesia was induced with alfentanil 10 μg/kg, propofol 2.5 mg/kg, and rocuronium 0.3 mg/kg. Each Time(EI) at which tracheal intubation was attempted was predetermined according to the up-and-down method. The values of Time(EI) that provided excellent intubation conditions in 50 and 95 % of patients were defined as Time(EI)50 and Time(EI)95, respectively.
Results: Time(EI)50 ± SD was 160 ± 26.2 and 150 ± 13.7 s in the control and atropine groups, respectively. Using isotonic regression, Time(EI)95 in the control and atropine groups was 199 s (95 % CI 198.8-200.7 s) and 171 s (95 % CI 171.3-172.1 s), respectively. Time(EI)95 was significantly higher in the control group than in the atropine group (P < 0.001). HR was significantly higher in the atropine group than in the control group during the study period.
Conclusions: This study demonstrated that the Time(EI)95 of a low dose of rocuronium (0.3 mg/kg) required for excellent tracheal intubation was 199 s during i.v. anesthesia induction using propofol and alfentanil in children. Also, i.v. atropine (10 μg/kg) before anesthesia induction was able to reduce Time(EI)95 by 28 s.