Background: Postoperative residual neuromuscular blockade (PRNB) is defined as an adductor pollicis train-of-four ratio (TOFR) <0.9. It is a common postoperative complication when nondepolarizing muscle relaxants are either not reversed or reversed with neostigmine. PRNB has been reported in 25% to 58% of patients who receive intermediate-acting nondepolarizing muscle relaxants, and it is associated with increased morbidity and decreased patient satisfaction. We conducted a prospective descriptive cohort study during the implementation of a practice guideline that included the selective use of sugammadex or neostigmine. The primary study aim of this pragmatic study was to estimate the incidence of PRNB at arrival to the postanesthesia care unit (PACU) when the practice guideline is followed.
Methods: We enrolled patients undergoing orthopedic or abdominal surgery requiring neuromuscular blockade. Rocuronium administration was guided by surgical requirements and based on ideal body weight, with dose reductions for women and/or age >55 years. Only qualitative monitoring was available to the anesthesia providers, and selection of sugammadex or neostigmine was guided by tactile assessments of the response to train-of-four (TOF) stimulation by a peripheral nerve stimulator. Neostigmine was administered if no fade was detected in the TOF response at the thumb. Deeper blocks were reversed with sugammadex. The prespecified primary and secondary end points were the incidence of PRNB at arrival to the PACU, defined as a normalized TOFR (nTOFR) < 0.9, and severe PRNB, defined as nTOFR <0.7 on arrival to the PACU. Anesthesia providers were blinded to all quantitative measurements made by research staff.
Results: Analysis included 163 patients, and 145 underwent orthopedic and 18 abdominal surgeries. Of the 163 patients, 92 (56%) were reversed with neostigmine and 71 (44%) with sugammadex. The overall incidence of PRNB at PACU arrival was 5 of 163 or 3% (95% confidence interval [CI], 1-7). The incidence of severe PRNB in PACU was 1% (95% CI, 0-4). Three of the 5 subjects with PRNB had TOFR <0.4 at time of reversal but were given neostigmine since anesthesia providers detected no fade by qualitative assessment.
Conclusions: The use of a protocol that specifies rocuronium dosing and selective use of sugammadex versus neostigmine based on qualitative assessment of TOF count and fade allowed us to achieve an incidence of PRNB of 3% (95% CI, 1-7) at PACU arrival. Quantitative monitoring may be needed to further reduce this incidence.
Trial registration: ClinicalTrials.gov NCT03543826.
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