Speaker
Description
Rocuronium is a lipophobic neuromuscular blocking agent used to induce muscle relaxation during surgery. Although its pharmacokinetic (PK) and pharmacodynamic (PD) properites have been extensively studied, differences between normal-weight and obese patients remain insufficiently characterized. In particular, it is unclear whether Rocuronium dynamics and effects differ between these groups and whether additional body-composition measures from bioimpedance analysis may improve predictive performance.
We analyzed data from 49 surgical patients with normal weight (body mass index (BMI) 19–34 kg/m²) or obesity (BMI 39–56 kg/m²). Rocuronium plasma concentrations and neuromuscular effects, assessed via evoked muscle contractions following electrical train-of-four stimulation, were measured repeatedly. Population PKPD models with different covariate structures were estimated using nonlinear mixed-effects modelling in Monolix. Models were compared using likelihood-based model selection criteria and predictive performance metrics. A virtual clinical trial with 1000 simulated patients was performed to explore clinical implications.
We observed improved model fit when estimating separate models for normal-weight and obese patients. In contrast, bioimpedance-derived covariates did not further enhance predictions. Simulations suggested that obese patients may require adapted dosing strategies to achieve comparable neuromuscular blockade to that in normal-weight patients during surgery.
