Interindividual Variability in Duration of Action of Rocuronium in Paediatric Patients (DurAct): A Prospective Observational Study

Background: In adult patients, rocuronium shows interindividual variability related to weight, sex, and age, but paediatric data are limited. This study aimed to evaluate clinical factors influencing the duration of action of rocuronium in children. Methods: Patients aged between 0 and 18 years undergoing planned general anaesthesia were eligible. The primary objective was to compare the duration of clinical action of rocuronium after a single dose, measured until the return of TOF (Train of Four) 1, across three-group age categories. Secondary objectives explored the relationship between TOF recovery and sex, weight, height, initial body temperature, as well as the occurrence of postoperative complications related to general anaesthesia. Results: Among 96 analysed patients, no clinically relevant association was found between the duration of rocuronium action and the studied clinical factors. TOF 1 occurred at 18.1 ± 9.5 min in those aged 1 to 5 years (n = 26), 16.8 ± 14.5 min in those aged 6 to 10 years (n = 33), and 18.2 ± 13.8 min in those aged 10 to 17 years (n = 37), p = 0.626. A post hoc analysis revealed high variability in recovery times across TOF levels, both in the per-protocol population (e.g., TOF 1: 17.7 ± 12.9 min) and in patients who did not receive sugammadex. Conclusions: In paediatric patients, the duration of rocuronium action after a single dose demonstrated substantial interindividual variability, which was not explained by age, sex, weight, height, or body temperature.