Background: In this investigation, we sought to determine the association between objective evidence of residual neuromuscular blockade (train-of-four [TOF] ratio <0.9) and the type, incidence, and severity of subjective symptoms of muscle weakness in the postanesthesia care unit (PACU).
Methods: TOF ratios of 149 patients were quantified with acceleromyography on arrival to the PACU. Patients were stratified into 2 cohorts: a TOF <0.9 group (n = 48) or a TOF ≥0.9 (control) group (n = 101). A standardized examination determined the presence or absence of 16 symptoms and 11 signs of muscle weakness on arrival to the PACU and 20, 40, and 60 minutes after admission.
Results: The incidence of symptoms of muscle weakness was significantly higher in the TOF <0.9 group at all times (P < 0.001), as was the median (range) number of symptoms from PACU arrival (7 [3-6] TOF <0.9 group vs 2 [0-11] control group; difference 5, 99% confidence interval of the difference 4-6) until 60 minutes after admission (2 [0-12] TOF <0.9 group vs 0 [0-11] control group; difference 2, 99% confidence interval of the difference 1-2) (all P < 0.0001).
Conclusion: The incidence and severity of symptoms of muscle weakness were increased in the PACU in patients with a TOF <0.9.