Residual neuromuscular blockade in the postanesthesia care unit: observational cross-sectional study of a multicenter cohort

BACKGROUND: Residual neuromuscular blockade after general anesthesia using nondepolarizing neuromuscular blocking agents has pathophysiological, clinical, and economic consequences. A significant number of patients under muscle relaxation sustain residual curarization. METHODS: Observational, prospective, multicenter study of a cohort of patients (Residual Curarization in Spain Study, ReCuSS). Residual blockade was defined as TOFr<0.9. Patients > 18 years-old under general anesthesia, including at least one dose of non-depolarizing neuromuscular blocking agents, and transferred extubated and spontaneously ventilating to the postanesthesia care unit were included. Pre- and intraoperative data were recorded, including, patient characteristics, ASA physical status, experience of the anesthesiologist, type of surgery, temperature monitoring, surgery duration, neuromuscular blockade-related parameters, type of anesthesia (halogenated-balanced, intravenous propofol-based, other), and use of neuromuscular monitoring. RESULTS: A total of 763 patients from 26 hospitals were included, 190 patients (26.7%) showing residual paralysis. Female patients were more prone to residual neuromuscular blockade. Length of surgery, type of relaxant used (benzyl-isoquinolines), halogenated anesthesia, absence of intraoperative specific monitoring, avoidance of drug reversal, and neostigmine reversal (vs. sugammadex), were significantly related to residual blockade. In the postanesthesia care unit, patients with residual neuromuscular blockade had an increased incidence of respiratory events and tracheal reintubation. CONCLUSIONS: The incidence of residual blockade in Spain is similar to that published in other settings and countries. Female gender, longer duration of surgery, and halogenated drugs for anesthesia maintenance were related to residual paralysis, as were NMBA specific items, such as the use of benzylisoquinoline drugs, and the absence of reversal or reversal with neostigmine.