Background: Postoperative residual curarization (PORC) is an important complication of neuromuscular blocking drug (NMBD) use. This study evaluates the incidence of PORC in the Postanesthesia Care Unit (PACU), its relation to the type of muscle relaxant and reversal agent used, and its implication in the development of postoperative respiratory complications.
Methods: A prospective observational study of cohorts was made with 558 patients operated under general anesthesia. Data regarding patient history, muscle relaxation (train-of-four [TOF]) monitoring, type of relaxants and reversal agents used, and TOF upon admission to the PACU was collected. Four groups were established: cisatracurium, cisatracurium-neostigmine, rocuronium, and rocuronium-sugammadex. An evaluation was made on the incidence of PORC (TOF ratio [TOFr] <0.9) in PACU, and its relation to the relaxants and reversal agents used and to the development of postoperative respiratory complications - minor and major (pneumonia, atelectasis).
Results: From a total of 558 patients, 27.9% presented with PORC. According to the NMBD used and the administration or not of a reversal agent, the incidence of PORC in the four groups was: cisatracurium 34%, cisatracurium-neostigmine 28.6%, rocuronium 34%, and rocuronium-sugammadex 1.15%. The global incidence of minor critical respiratory events (CREs) was 14.5%: cisatracurium 27.5%, cisatracurium-neostigmine 17.4%, rocuronium 10.5%, and rocuronium-sugammadex 2.3%, with statistically significant differences. The global incidence of major CREs was 7.5%, and was significantly higher in patients with TOFr<0.9 upon admission to the PACU.
Conclusions: PORC in the PACU is associated to a greater incidence of major and minor respiratory complications. The use of rocuronium-sugammadex significantly reduces the incidence of PORC in the PACU.