Optimizing Neostigmine Dosing for Neuromuscular Blockade Reversal: A Randomized Controlled Trial Assessing Diaphragmatic Recovery After Laparoscopic Cholecystectomy

BackgroundResidual neuromuscular blockade (RNMB)can impair diaphragmatic function and increase the risk of postoperative respiratory complications, especially after laparoscopic procedures where ventilatory mechanics are already compromised. Neostigmine is still the most frequently employed reversal agent, but its optimal dosing balancing efficacy and side effects has not been clearly established. This study aims to assess whether a lower neostigmine dose (0.04mg/kg) restores diaphragmatic function as effectively as the standard dose (0.08mg/kg), while minimizing cholinergic side effects, in patients undergoing elective laparoscopic cholecystectomy.MethodsIn a double-blind, randomized controlled trial, 50 ASA I–II adult patients were assigned to receive either full-dose or half-dose neostigmine, each with atropine (0.02mg/kg), at a train-of-four (TOF) count ≥2. Diaphragmatic function was assessed using bedside ultrasonography measuring diaphragmatic excursion (DE) and diaphragmatic thickening fraction (DTF) at baseline, and at 0, 10 and 30 minutes after reversal. Secondary outcomes included arterial blood gases (ABGs), hemodynamic and respiratory variables, cholinergic side effects, and post-anesthesia care unit (PACU) stay.ResultsBoth groups showed a significant postoperative reduction in DE and DTF (p<0.001), with no statistically significant differences between groups. The full-dose group exhibited significantly higher rates of vomiting (48% vs. 16%), bradycardia (40% vs. 12%), and salivation (48% vs. 20%) (p<0.05). ABG values, hemodynamics, and PACU duration were similar between groups.ConclusionA reduced neostigmine dose (0.04mg/kg) provides equivalent diaphragmatic recovery compared to the standard dose, with fewer cholinergic side effects. These findings support a monitoring-guided, individualized approach to neuromuscular block reversal in low-risk patients.