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

Brunaud and Fuchs-Buder wrote a letter in response to our recent study to bring the selective sugammadex reversal approach for neural monitoring to the attention of readers. They stated that the need for sugammadex to restore neuromuscular function allowing adequate intraoperative neuromonitoring (IONM) is rather infrequent and observed in less than approximately 20% of patients. Consequently, compared to routine reversal of rocuronium neuromuscular blockade with sugammadex, a selective reversal approach may be sufficient and more cost-effective. First, we accept as true that recovery from rocuronium-induced neuromuscular blockade is significantly faster at the laryngeal muscles compared to the adductor pollicis muscle. Appropriate IONM may be allowed in most patients while the adductor pollicis is still paralyzed. However, the dose of rocuronium and the time of nerve stimulation is critical for successful IONM. In our previous study, in the patients who received a standard intubating dose of rocuronium (0.6 mg/kg), the rate of positive electromyographic (EMG) response from vagal stimulation was only 53% at 30 minutes after rocuronium injection; only at 55 minutes did the rate of positive EMG response reach 100% in these patients. Furthermore, the mean EMG amplitude was markedly lower from 30 to 60 minutes. Second, a higher initial EMG signal is also crucial as 1) it can be as a reference to be compared with the final signal to predict the outcome of vocal cord function, 2) it is helpful to map the path of the recurrent laryngeal nerve intraoperatively, and 3) it is useful to detect early adverse signal change to prevent imminent nerve injury, particularly for continuous IONM. Third, because sugammadex is currently an expensive product, a selective reversal approach may be more cost-effective. However, we have to emphasize that when a standard dose of rocuronium (0.6 mg/kg) is used for tracheal intubation, the recovery from neuromuscular blockade after rocuronium varies widely between subjects and may lead to a false-negative IONM result. If we take the cost of sugammadex into consideration, a reduced dosage of rocuronium (0.3 mg/kg) can be another option.