Background: The subjective experience of residual neuromuscular blockade after emergence from anesthesia has not been examined systematically during postanesthesia care unit (PACU) stays. The authors hypothesized that acceleromyography monitoring would diminish unpleasant symptoms of residual paresis during recovery from anesthesia by reducing the percentage of patients with train-of-four ratios less than 0.9.
Methods: One hundred fifty-five patients were randomized to receive intraoperative acceleromyography monitoring (acceleromyography group) or conventional qualitative train-of-four monitoring (control group). Neuromuscular management was standardized, and extubation was performed when defined criteria were achieved. Immediately upon a patient's arrival to the PACU, the patient's train-of-four ratios were measured using acceleromyography, and a standardized examination was used to assess 16 symptoms and 11 signs of residual paresis. This examination was repeated 20, 40, and 60 min after PACU admission.
Results: The incidence of residual blockade (train-of-four ratios less than 0.9) was reduced in the acceleromyography group (14.5% vs. 50.0% control group, with the 99% confidence interval for this 35.5% difference being 16.4-52.6%, P < 0.0001). Generalized linear models revealed the acceleromyography group had less overall weakness (graded on a 0-10 scale) and fewer symptoms of muscle weakness across all time points (P < 0.0001 for both analyses), but the number of signs of muscle weakness was small from the time of arrival in the PACU and did not differ between the groups at any time.
Conclusion: Acceleromyography monitoring reduces the incidence of residual blockade and associated unpleasant symptoms of muscle weakness in the PACU and improves the overall quality of recovery.