The incidence of residual neuromuscular blockade and its association with reversal agent choice using quantitative train-of-four monitoring

Study objective To determine the incidence of residual neuromuscular blockade (rNMB) on post-anesthesia care unit (PACU) admission using quantitative train-of-four (TOF) monitoring and to examine its association with reversal agent choice. Design Single-center ambidirectional observational cohort study with a prospective cohort and a retrospective cohort for contextual comparison. Setting Academic tertiary care center. Patients Adults (≥18 years) undergoing surgery with general anesthesia with nondepolarizing neuromuscular blockade ( n = 622; 311 retrospective, 311 prospective). Intervention Prospective patients underwent quantitative TOF monitoring on PACU admission. Measurements Primary outcome was rNMB (TOF <0.9). Secondary measures included neuromuscular blockade reversal agent use and postoperative outcomes. Main results In the prospective cohort, rNMB was observed in 20.3% of patients. rNMB was more frequent in patients who received neostigmine compared with sugammadex (24.9% vs. 3.0%). Most patients with rNMB achieved recovery following supplemental sugammadex in the PACU. Differences in postoperative outcomes between cohorts were observed; however, these findings should be interpreted cautiously given potential confounding and differences in cohort characteristics. Conclusion Residual neuromuscular blockade remains common in routine practice when assessed with qualitative monitoring. Qualitative TOF assessment alone may not reliably exclude rNMB. These findings support broader use of quantitative neuromuscular monitoring and careful selection of neuromuscular blockade reversal strategies to enhance perioperative safety.