Some anaesthetists wonder whether confirming a train-of-four ratio (TOFR) ≥0.9 is necessary when using sugammadex to antagonise neuromuscular blockade (NMB). In this study, we aimed to determine whether using sugammadex at the recommended dose under neuromuscular monitoring (NMM) would ensure complete recovery, even without further NMM.

This prospective observational study included 51 patients who underwent robot-assisted surgery under general anaesthesia between March and May 2023. At the end of surgery, sugammadex was administered (2 mg/kg for a train-of-four (TOF) count ≥1 and 4 mg/kg for a TOF count = 0 and a post-tetanic count ≥1). NMM was discontinued, and subsequent recovery was completed at the discretion of the attending anaesthetist. TOFR was measured twice immediately upon admission to the post-anaesthesia care unit (PACU). The primary outcome was the incidence of a non-normalised TOFR (nTOFR) <0.9 upon arrival in PACU. The secondary outcomes were the incidences of a nTOFR <0.7 or 1.0, symptoms/signs of residual NMB (diplopia, dyspnoea, and desaturation) and recovery profiles in PACU.

The incidence of a nTOFR <0.9 upon arrival in PACU was 5.9% (3/51 patients). No patient had a nTOFR <0.7, and 47.1% (24 patients) had a nTOFR <1.0, but no patients showed clinical symptoms/signs of residual NMB.

When the recommended dose of sugammadex was administered under qualitative NMM, residual NMB at the time of PACU arrival occurred frequently, indicating that quantitative NMM is necessary to ensure adequate recovery.

ClinicalTrials, NCT 05760560.