Reversal of Rocuronium-Induced Muscle Relaxation with Sugammadex Enhances Oxygen Metabolism in Skeletal Muscle

We measured changes in blood flow and oxygenation in the brachioradialis muscle using near-infrared spectroscopy (NIRS) during reversal of rocuronium-induced muscle relaxation with administration of sugammadex in patients (n = 25) under general anaesthesia, to investigate whether reversal of muscle relaxant-induced muscle relaxation increases oxygen metabolism in skeletal muscle under general anaesthesia. NIRS measurements, including oxy-haemoglobin (Hb), deoxyHb, total Hb concentration, tissue oxygen index, and various cardiopulmonary parameters, were recorded at four timepoints: T0 (baseline), 3 min before sugammadex administration; T1, immediately before sugammadex administration; T2, at complete recovery of muscle contractility; and T3, 3 min after T2. All measured values at each timepoint were compared using multiple comparison tests. The median values (quartile deviation; QD) (μmol/L) of oxyHb and deoxyHb at T0, T1, T2, and T3 were 0, −0.01 (0.14), −1.15 (0.54), and −1.52 (0.54), and 0, 0.11 (0.06), 0.86 (0.5), and 1.36 (0.61), respectively. The levels of oxyHb were significantly lower and those of deoxyHb were significantly higher at T2 and T3 when compared to those at T1, respectively (P < 0.01). There were no significant changes in other measurements. These results suggest that reversal of rocuronium-induced muscle relaxation by sugammadex slightly increases oxygen metabolism in the brachioradialis muscle. This study might support the clinical finding that administration of neuromuscular blockers decreases whole body oxygen consumption in patients receiving mechanical ventilation under general anaesthesia.