Comparison of Different Neostigmine Doses for Reversal of Cisatracurium‐Induced Neuromuscular Block in Children Under Total Intravenous Anesthesia: A Randomized Controlled Trial

BACKGROUND: Neostigmine is widely used to reverse nondepolarizing neuromuscular blockade in children, but the optimal dose under total intravenous anesthesia is uncertain. AIMS: The primary aim was to compare the time to full neuromuscular recovery (TOF ratio of 1.0) following administration of neostigmine at doses of 0, 10, 20, and 30 μg/kg in children at a TOF count of 3. Secondary objectives were full reversal within 10 min and adverse events. METHODS: This prospective, randomized, double-blind, parallel-group, superiority trial enrolled 120 children (2-10 years; ASA I-II) undergoing tonsillectomy. Participants received 0, 10, 20, or 30 μg/kg neostigmine at a TOF count of 3 measured by quantitative acceleromyography. The primary outcome was the time from TOF count of 3 to full reversal (TOF ratio = 1.0). Secondary outcomes were the proportion of patients achieving full reversal within 10 min and adverse events. Comparisons among active groups used the Kruskal-Wallis test. RESULTS: A total of 118 patients were analyzed. Median [IQR] time to full reversal was 20.2 [14.8-24.1], 14.0 [10.7-16.8], 11.0 [8.2-15.5], and 11.2 [7.9-14.6] min in the 0, 10, 20, and 30 μg/kg groups, respectively. Reversal was significantly slower in the control group compared with all neostigmine doses. However, there was no statistically significant difference among the active doses (Kruskal-Wallis, p = 0.33). At 10 min, full reversal had occurred in 10.7%, 23.3%, 43.3%, and 33.3% of patients in the respective groups. Adverse events were uncommon, occurring in 10 of 118 patients, and consisted exclusively of transient bradycardia and tachycardia, without differences among groups. CONCLUSIONS: At TOF count of 3, neostigmine 10-30 μg/kg shortened reversal compared with no reversal, but doses above 10 μg/kg conferred no additional benefit. Quantitative monitoring remains essential, as fewer than half of patients achieved a TOF ratio of 1.0 within 10 min. TRIAL REGISTRY: https://ensaiosclinicos.gov.br/rg/RBR-4xrx2g3.