A prospective, observational study comparing postoperative residual curarisation and early adverse respiratory events in patients reversed with neostigmine or sugammadex or after apparent spontaneous recovery

Six years ago, a study performed in our department reported that the incidence of postoperative residual curarisation (PORC) was 39%. The reassessment of neuromuscular monitoring and reversal of neuromuscular block in routine anaesthetic practice is relevant now that sugammadex has become available. The incidence of PORC, defined by a train-of-four (TOF) <90%, was evaluated at post-anaesthesia care unit (PACU) arrival in patients whose neuromuscular block had been reversed with neostigmine or sugammadex and those in whom reversal was felt unnecessary (adequate spontaneous recovery). During the PACU stay we recorded the oxygen saturation (SpO(2)) at arrival, episodes of SpO(2) <90%, airway manoeuvres and/or stimulation required to maintain SpO(2) >90%, and the need for re-intubation. In total, 624 patients were studied. Fifteen percent (66/441) of the patients who were not reversed, 15% (21/139) of those who were reversed with neostigmine and 2% (1/44) of those who received sugammadex exhibited PORC (P=0.06). No patient required reintubation in the PACU. The absence of neuromuscular monitoring and pharmacological reversal before extubation were not associated with PORC. A TOF <90% at PACU arrival was not associated with SpO(2) <90% during the PACU stay. Body mass index was the only independent predictor of SpO(2) <90% during the stay in the PACU. These findings indicate that in recent years, the incidence of PORC, defined by a TOF <90%, has dramatically decreased in our institution. The differences in PORC were not statistically significant between patients who received sugammadex for reversal and patients with spontaneous recovery or neostigmine reversal.