In response toReversal of rocuronium-induced neuromuscular blockade by sugammadex allows for optimization of neural monitoring of the recurrent laryngeal nerve

Precision Neuromuscular Block Management for Neural Monitoring During Thyroid Surgery

INTRODUCTION

Titration of neuromuscular block (NMB) plays a key role in intraoperative recurrent laryngeal nerve monitoring during thyroid surgery. The combination of neuromuscular blocking agent and timely partial reversal of NMB was investigated in both animal experiments and clinical neuro-monitored thyroidectomy.

METHODS

In animal experiments, 8 piglets received sugammadex to assess the laryngeal EMG recovery after rocuronium-induced NMB. In clinical monitored thyroidectomy, 40 patients each were allocated to conventional group and sugammadex group. Conventional group received rocuronium 0.3 mg/kg at anesthesia induction, while sugammadex group received partial NMB recovery protocol- 0.6 mg/kg of rocuronium at anesthesia induction and 0.5 mg/kg of sugammadex. Main outcome was assessed by first (V1) and final (V2) EMG signal induced by vagal stimulation.

RESULTS

In the porcine model, 50% recovery of laryngeal EMG amplitude was achieved at 16.8 ± 1.9 and 6 ± 2.7 minutes respectively after 0.5 and 1 mg/kg of sugammadex (p < 0.01). In monitored thyroidectomy, EMG amplitudes at V1 in group S and group C were 1214 ± 623 and 915 ± 476 μV, respectively (p = 0.02). Positive and adequately high EMG amplitudes were observed at the early surgical stage for all patients. Sugammadex groups were superior to conventional group in EMG tube placement (p < 0.001).

CONCLUSION

Both porcine model and clinical application showed that precise NMB management by low-dose sugammadex was effective for intraoperative neural monitoring (IONM). The regimen ensured optimal conditions for tracheal intubation and timely neuromuscular function restoration for high-quality EMG signal.

Neuromuscular blockade management for intraoperative neural monitoring

This article reviews the literature on development of neuromuscular blockade management in thyroid surgery with intraoperative neural monitoring (IONM) in the past decade. Neuromuscular blockade management includes the choice of neuromuscular blocking agents (NMBAs) and reversal of neuromuscular blockade by sugammadex. A series of animal study and clinical trials showed NMBAs effect on IONM in thyroid surgery. We summarized five NMBA regimens for IONM: (a) relaxant-free regimen, (b) depolarizing NMBA-succinylcholine, (c) titration of nondepolarizing NMBA, and (d) rocuronium combined with sugammadex. The proper management of neuromuscular blockade during IONM has greatly developed over the past decade. The misuse of NMBAs is associated with false IONM interpretations to surgeons. A detailed understanding of NMBAs and neuromuscular blockade management by sugammadex may optimize IONM quality in patients receiving monitored thyroid surgery.

Intraoperative neural monitoring in thyroid surgery: lessons learned from animal studies

Recurrent laryngeal nerve (RLN) injury remains a significant morbidity associated with thyroid and parathyroid surgery. In the past decade, surgeons have increasingly used intraoperative neural monitoring (IONM) as an adjunct technique for localizing and identifying the RLN, detecting RLN injury, and predicting the outcome of vocal cord function. In recent years, many animal studies have investigated common pitfalls and new applications of IONM. For example, the use of IONM technology in animal models has proven valuable in studies of the electrophysiology of RLN injury. The advent of animal studies has substantially improved understanding of IONM technology. Lessons learned from animal studies have immediate clinical applications in establishing reliable strategies for preventing intraoperative RLN injury. This article gives an overview of the research progress on IONM-relevant animal models.