Quantitative Neuromuscular Monitoring in General Anesthesia: A Systematic Review of Recovery and Safety Outcomes.

Quantitative neuromuscular monitoring is increasingly used during general anesthesia to confirm recovery after neuromuscular blocking agents (NMBAs) and reduce postoperative respiratory risk. Residual neuromuscular blockade remains a preventable concern, yet monitoring practices, device performance, reversal use, and recovery thresholds remain variable across perioperative settings. This systematic review evaluated evidence on quantitative neuromuscular monitoring in general anesthesia, focusing on recovery assessment, residual blockade detection, device agreement, reversal practice, and postoperative safety outcomes. Literature was searched in PubMed/MEDLINE, Scopus, Google Scholar, and Web of Science. After duplicate removal, screening, and eligibility assessment, 10 studies were included for qualitative synthesis. Data were extracted on study design, sample size, monitoring modality, recovery thresholds, respiratory events, and key findings. Risk of bias was assessed using the Cochrane Risk of Bias 2 tool (RoB 2) for randomized studies and the Risk of Bias in Non-randomized Studies of Interventions (ROBINS-I) for non-randomized studies. The included studies showed that train-of-four (TOF)-based assessment was central to identifying incomplete recovery, commonly using a TOF ratio of at least 0.90. Residual blockade was associated with oxygen requirement, hypoxemia, critical respiratory events, and pulmonary complications. Device comparisons showed that acceleromyography, electromyography, TOF-Cuff, TOF-Scan, and ultrasonography were not always interchangeable. Routine quantitative monitoring with correct interpretation may improve extubation safety and postoperative recovery.