Electromyographic activity of the diaphragm during neostigmine or sugammadex-enhanced recovery after neuromuscular blockade with rocuronium A randomised controlled study in healthy volunteers

BACKGROUND The use of neuromuscular blocking agents has been associated with severe postoperative respiratory morbidity. Complications can be attributed to inadequate reversal, and reversal agents may themselves have adverse effects. OBJECTIVE To compare the electromyographic activity of the diaphragm (EMGdi) during recovery from neuromuscular blockade using neostigmine and sugammadex. The hypothesis was that there would be better neuromuscular coupling of the diaphragm when sugammadex was used. DESIGN A randomised, controlled, parallel-group, single-centre, double-blinded study. SETTING District general hospital in Belgium. PARTICIPANTS Twelve healthy male volunteers. INTERVENTIONS Individuals were anaesthetised with propofol and remifentanil. After rocuronium 0.6 mg kg(-1), a transoesophageal electromyography (EMG) recorder was inserted. For reversal of neuromuscular blockade, volunteers received sugammadex 2 mg kg(-1) (n = 6) or neostigmine 70 mu g kg(-1) (n = 6). MAIN OUTCOME MEASURES EMGdi, airway pressure and flow were continuously measured during weaning from the ventilator until tracheal extubation. Arterial blood gas samples were obtained for PaO2 and PaCO2 analysis at the first spontaneous breathing attempt and after tracheal extubation. RESULTS During weaning, 560 breaths were retained for analysis. The median (95% CI) peak EMGdi was 1.1 (0.9 to 1.5) mu V in the neostigmine group and 1.6 (1.3 to 1.9) mV in the sugammadex group (P < 0.001). Individuals in the neostigmine group had 125 of 228 (55%) breaths with associated EMGdi at least 1 mV vs. 220 of 332 (66%) breaths in the sugammadex group (P = 0.008). The median (95% CI) tidal volume was 287 (256 to 335) ml after neostigmine and 359 (313 to 398) ml after sugammadex (P = 0.013). The median (95% CI) PaO2 immediately after extubation was 30.5 (22.8 to 37.1) kPa after sugammadex vs. 20.7 (12.9 to 27.5) kPa after neostigmine (P = 0.03). CONCLUSION EMGdi, tidal volume and PaO2 following tracheal extubation were increased after sugammadex compared with neostigmine, reflecting diaphragm-driven inspiration after sugammadex administration. Sugammadex may free more diaphragmatic acetylcholine receptors than neostigmine, which has an indirect effect.