Incidence of postoperative residual neuromuscular blockade: a prospective observational study

Introduction: The use of non-depolarizing neuromuscular blockers (ND-NMB) is essential in anesthetic management as it improves ventilation conditions, airway management, and surgical conditions. However, the residual neuromuscular blockade (RNMB) in the immediate postoperative period derived from the use of these agents is associated with complications such as desaturation, pneumonia, and unplanned intensive care unit admission. The incidence varies significantly across different studies, and associated risk factors have not been consistent. Objectives: To estimate the incidence of RNMB and to identify characteristics of intraoperative management and potential risk factors for RNMB. Methods: A prospective observational study was conducted at a university hospital, using convenience sampling. Train-of-four (TOF) measurements were performed in the post-anesthesia care unit. An exploratory multivariate analysis was performed to identify potential risk factors. Results: A total of 300 patients were included. The incidence of residual neuromuscular blockade (RNMB) was 19% (95% CI: 14.9% - 23.8%). Evidence of relaxation monitoring was observed in 21.3% of the patients. Significant associations with RNMB were found for female gender (OR 1.97, 95% CI 1.02 – 3.81), absence of pharmacological reversal (OR 2.31, 95% CI 1.02 – 5.24), abdominal surgery (OR 2.81, 95% CI 1.37 – 5.72), and multiple intraoperative doses of ND-NMBs (OR 2.77, 95% CI 1.48 – 5.18). Conclusions: Residual neuromuscular blockade (RNMB) is common in our setting, with a low frequency of intraoperative monitoring. The associated risk factors identified can point to specific scenarios that require special attention.