Effects of High Neuromuscular Blocking Agent Dose on Postoperative Respiratory Complications in Infants and Children

BACKGROUND: This study evaluated the association between neuromuscular blocking agent dose and post-operative respiratory complications in infants and children. METHODS: Data from 6507 general anaesthetics provided to children aged 0-10 years undergoing surgery were analysed to examine the effects of neuromuscular blocking agent dose on post-operative respiratory complications (primary endpoint) and secondary endpoints. Confounder-adjusted analyses addressed age, surgical duration, and comorbidity burden. RESULTS: In confounder-adjusted analyses, high doses of neuromuscular blocking agents were associated with higher risk of post-operative respiratory complications (OR 2.27; 95% CI 1.12-4.59; P = .022). The effect was modified by age (P-for-interaction = .016) towards a more substantial risk in infants 1: OR 3.17; 95% CI 1.43-7.04; P = .005). Neostigmine reversal did not modify the association between neuromuscular blocking agents and post-operative respiratory complications (P-for-interaction = .38). Instrumental variable analysis confirmed that high doses of neuromuscular blocking agents were associated with post-operative respiratory complications (probit coefficient 0.25; 95% CI 0.04-0.46; P = .022), demonstrating robust results regarding concerns of unobserved confounding. CONCLUSIONS: High dose of neuromuscular blocking agents is associated with post-operative respiratory complications. We have identified subcohorts of paediatric patients who are particularly vulnerable to the respiratory side-effects of neuromuscular blocking agents: infants, paediatric patients undergoing surgeries of short duration, and those with a high ASA risk score.