Continuous Rocuronium Administration Method Based on Pharmacokinetic/ Pharmacodynamics Model during Propofol, Sevoflurane, and Desflurane Anesthesia

Purpose: Although rocuronium bromide (Rb) is suitable for continuous administration use, determination of optimal continuous doses is difficult due to individual differences. This study examines the efficacy of a continuous Rb administration method based on effect-site concentrations calculated by a pharmacokinetic/pharmacodynamics model during propofol, sevoflurane, and desflurane anesthesia. Methods: The 36 enrolled patients were equally divided into three groups (P; propofol, S; sevoflurane, and D; desflurane groups). After induction and administration of Rb 0.6 mg/kg, we calculated the simulated effect-site concentration at the point which the first twitch (%T1) recovered to > 0% and defined this as the Rb recovery concentration (Rbr.c.) level appropriate for continuous rocuronium administration. The continuous administration doses of Rb were adjusted to maintain Rbr.c. during surgery. The Rbr.c. and the recovery time at %T1 > 25% were recorded for each type of anesthesia. Results: Rbr.c. (μg/mL) for the P, S, and D groups were 1.54 ± 0.2, 1.24 ± 0.2, and 1.09 ± 0.2, respectively. Continuous administration doses (μg/kg/min) in the P, S, and D group were 6.7 ± 0.9, 5.2 ± 1.0, and 4.5 ± 0.8, respectively. Rbr.c. and continuous doses in the S and D groups were lower than the P group. Neuromuscular relaxations during surgery in the S and D groups were more strongly maintained than for the P group. There was also a significantly prolonged recovery duration for the %T1 > 25% in the D versus the other two groups (P < 0.05). Conclusion: Results showed that our continuous administration method was effective for maintaining sufficient muscle relaxation without excessively prolonged recovery effects for both sevoflurane and desflurane as well as propofol anesthesia.