A Randomized Trial Evaluating Actual Versus Ideal Body Weight Dosing of Sugammadex in Morbidly Obese Patients 

Background: This randomized, double-blind trial evaluated sugammadex-mediated recovery time from rocuronium- or vecuronium-induced moderate (M-) or deep neuromuscular block (D-NMB) in morbidly obese adults dosed by actual (ABW) or ideal body weight (IBW). Methods: Adults with BMI ≥40 kg/m2 were randomized to 1 of 5 groups: M-NMB, sugammadex 2 mg/kg ABW; M-NMB, sugammadex 2 mg/kg IBW; M-NMB, neostigmine 5 mg, and glycopyrrolate 1 mg; D-NMB, sugammadex 4 mg/kg ABW; or D-NMB, sugammadex 4 mg/kg IBW. Supramaximal train of four (TOF) stimulation of the ulnar nerve (TOF-watch SX®) monitored recovery. Primary endpoint was time to TOF ratio ≥0.9 for ABW and IBW groups pooled across NMB agent (NMBA)/blocking depth, analyzed by log-rank test stratified for agent and depth. Prespecified safety outcomes included treatment-emergent bradycardia, tachycardia, and other arrhythmias, and adjudicated hypersensitivity and anaphylaxis. Results: Of 207 patients randomized, 188 received treatment (28% male, BMI 47±5.1 kg/m2, age 48±13 years). Recovery was 1.5 min faster with ABW vs IBW dosing. The sugammadex 2 mg/kg groups recovered 9-fold faster [time 0.11-fold, 95% CI 0.08 to 0.14] than the neostigmine group. ABW (5.3%) and IBW (2.7%) groups had similar incidences of recovery time >10 min (95% CI of difference: -4.8% to 11.0%); 84% for neostigmine group. Re-curarization occurred in one patient each in the 2 mg/kg IBW and neostigmine groups. Prespecified safety outcomes occurred with similar incidences. Conclusions: ABW-based sugammadex dosing yields faster reversal without re-curarization, supporting ABW-based sugammadex dosing in the morbidly obese, irrespective of the depth of NMB or NMBA used. Trial registration: Registered on November 17, 2017, at ClinicalTrials.gov under number NCT03346070. https://clinicaltrials.gov/ct2/show/results/NCT03346070?term=NCT03346070&draw=2&rank=1