Comparison of reversal between sugammadex and neostigmine in children with standardization of the rocuronium effect-site concentration: a randomized controlled trial

Background Residual neuromuscular blockade remains an important safety concern in pediatric anesthesia. Comparisons between sugammadex and neostigmine are often confounded by between-patient variability in rocuronium exposure at reversal. This study compared these reversal agents under conditions designed to standardize rocuronium effect-site exposure immediately before reversal. Methods Children aged 2–7 years undergoing elective tonsillectomy with or without adenoidectomy were randomized and blinded to receive sugammadex 2 mg/kg or neostigmine 0.06 mg/kg. Rocuronium was administered using a target-controlled infusion technique. The effect-site concentration was maintained at 1 μg/mL, and reversal was administered only after reappearance of the second twitch on train-of-four stimulation. The primary endpoint was the time from reversal to recovery of a train-of-four ratio (TOFR) of 0.90. A published mechanistic rocuronium-sugammadex pharmacokinetic-pharmacodynamic model was used, with fixed nontarget parameters, to estimate the reversal-related effect-site parameter and simulate recovery. Results Thirty-four children were analyzed (18 sugammadex, 16 neostigmine). The time to a TOFR of 0.90 was shorter with sugammadex than with neostigmine (102.0±38.2 seconds vs. 253.1±128.5 seconds; p<0.01). Extubation occurred earlier in the sugammadex group (327.2±148.0 seconds vs. 468.8±158.4 seconds; p<0.05), whereas the time to spontaneous breathing did not differ significantly between groups. In a representative-child simulation, recovery to a TOFR of 0.90 was approximately 3.5 minutes faster with sugammadex under otherwise identical assumptions. Conclusions When rocuronium exposure at the time of reversal was standardized, sugammadex achieved markedly faster quantitative neuromuscular recovery than neostigmine in children. Model-based simulations supported that this difference was consistent with enhanced effect-site recovery with sugammadex.