Ideal Versus Actual Body Weight for Dosage of Sugammadex in Patients With Body Mass Index Less Than 18.5: A Randomized Controlled Trial

Introduction: To date, no study has evaluated the appropriate sugammadex dose in underweight patients. Therefore, we aimed to compare time to recovery from deep neuromuscular block after administration of sugammadex based on either actual or ideal body weight in patients with a body mass index (BMI) of less than 18.5 kg/m2. Methods: Patients with a BMI < 18.5 kg/m2 who underwent elective surgery under general anesthesia were enrolled. Anesthesia was induced and maintained with total intravenous anesthesia. Train-of-four (TOF) responses were monitored at the abductor digiti minimi muscle using electromyography following administration of rocuronium 0.6-0.9 mg/kg. An additional dose of rocuronium 0.2 mg/kg was administered to maintain deep neuromuscular block. When the post-tetanic count reached 1 or 2, sugammadex 4 mg/kg was administered, calculated based on either actual or ideal body weight. The primary outcome was the time from sugammadex administration to a TOF ratio ≥ 90%. Data were analyzed using the unpaired t-test, with statistical significance defined as p < 0.05. Results: A total of 32 patients were included in the analysis. The difference between the actual and ideal body weight groups was not statistically significant (185.6 ± 89.5 s vs 147.3 ± 71.0 s; p = 0.19). Conclusion: There was no significant difference in sugammadex recovery time from deep neuromuscular block between dosing based on actual body weight and dosing based on ideal body weight in underweight patients.