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Effect of remimazolam on intraoperative neuromonitoring during thyroid surgery: a case series


Intraoperative neuromonitoring is widely used to prevent accidental injury during thyroid surgery. Anesthesia should be performed without muscle relaxant or agents with high muscle-relaxant potency. Remimazolam, a novel intravenous anesthetic, became available for clinical use in 2020. Remimazolam is an ultra-short-acting benzodiazepine with a very high clearance rate. However, there are very few data regarding its effect on currently used intraoperative neurological monitoring. Five patients underwent thyroid surgery using intraoperative recurrent laryngeal neuromonitoring. In all cases, intubation was performed after the administration of rocuronium. Anesthesia was maintained by continuous administration of remimazolam at the recommended dose and remifentanil, and no additional rocuronium or sugammadex was administered. Recurrent laryngeal nerve activity could be detected at the first stimulus after surgery was started, and monitoring continued thereafter. Intraoperative monitoring was performed without problems and all surgeries were completed without any complications. Anesthesia with remimazolam at the normal dose did not prolong the time to first positive electromyogram in patients undergoing thyroid surgery, and enables intraoperative recurrent laryngeal nerve monitoring to be performed without any serious perioperative adverse events. Remimazolam may provide a comparable quality of anesthesia to that of existing drugs for neuromonitoring during thyroid surgery.

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Fig. 1

Availability of data and materials

The datasets are available from the corresponding author on reasonable request.



Recurrent laryngeal nerve


Intraoperative neuromonitoring


Neuromuscular blocking agents


Nerve integrity monitor




Bispectral index


Compound muscle action potential


Gamma-aminobutyric acid


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The authors wish to thank Shoto Yamada of the Department of Clinical Engineering, Sapporo Medical University Hospital, for assistance with management of perioperative neuromonitoring.


The authors have no sources of funding to declare related to this manuscript.

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KH, TC, and ST examined the patients and performed anesthetic management. NH drew up the management plan and made revisions to the manuscript. KH wrote the manuscript. MY made critical revision and contributed to the writing of the manuscript. All authors approved the final version of the manuscript.

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Correspondence to Kengo Hayamizu.

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Ethics approval is not applicable because this manuscript is a case series.

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Written informed consent was obtained from the patients for the publication of this case series.

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Hayamizu, K., Chaki, T., Tachibana, S. et al. Effect of remimazolam on intraoperative neuromonitoring during thyroid surgery: a case series. J Anesth 35, 581–585 (2021).

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  • Remimazolam
  • Neuromonitoring
  • NIM monitoring
  • Intravenous anesthesia