Reversal of profound and "deep" residual rocuronium-induced neuromuscular blockade by sugammadex: a neurophysiological study

BacKground. Sugammadex is the first of a new class of selective relaxant binding drugs developed for the rapid and complete reversal of neuromuscular blockade (NMB) induced by the aminosteroid neuromuscular blocking drugs rocuronium and vecuronium. Neuromuscular blocking drugs block the transmission from the peripheral nerve to the muscle units, with reduction and disappearance of the evoked electromyographic activity. Usually, neuromuscular monitoring for the investigational reversal drug is performed by calibrated acceleromyography. The efficacy of sugammadex in reversing profound and "deep" residual rocuronium-induced NMB using myogenic motor evoked potentials (mMEPs) monitoring was evaluated. Methods. In this prospective trial, 30 consenting patients undergoing propofol-remifentanil anesthesia for spine surgery were enrolled and divided into two groups: Group 1, reversal of profound NMB (sugammadex 16 mg/Kg, 3 minutes after rocuronium 1.2 mg/Kg) and Group 2, reversal of "deep" residual NMB (sugammadex 4 mg/Kg, 15 minutes after rocuronium 0.6 mg/Kg). Myogenic MEPs registrations of upper and lower limbs and the diaphragm were performed, as well as TOF monitoring. Results. After injection of 4 mg/Kg of sugammadex, the means of recovery time of the basal mMEPs amplitudes (diaphragm, and lower limbs and upper limbs) were 124 +/- 9.6, 143 +/- 163, 151 +/- 207 sec, respectively whereas after 16 mg/Kg of sugammadex the times were 109 +/- 13.8, 124 +/- 0.6, and 135 +/- 14.1 sec. Times to TOF ratio 0.9 were 114 +/- 75 and 186 +/- 105 sec in Group 1 and 2, respectively. No serious adverse effects related to sugammadex and to electrical stimulation were reported. No reoccurrence of neuromuscular block was observed. Conclusion. Neurophysiological monitoring using mMEPs confirmed that sugammadex provided a complete recovery from profound and "deep" residual rocuronium-induced neuromuscular blockade. (Minerva Anestesiol 2012;78:542-9)