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Comparison of remimazolam and dexmedetomidine for intraoperative sedation in patients undergoing lower extremity surgery under spinal anesthesia: a randomized clinical trial
  1. Hansol Kim1,
  2. Youngwon Kim2,
  3. Jinyoung Bae3,
  4. Seokha Yoo1,
  5. Young-Jin Lim1,4 and
  6. Jin-Tae Kim1,4,5
  1. 1Department of Anesthesiology and Pain Medicine, Seoul National University Hospital, Seoul, Korea
  2. 2Department of Anesthesiology and Pain Medicine, Anesthesia and Pain Research Institute, Yonsei University College of Medicine, Seoul, Korea
  3. 3Department of Anesthesiology and Pain Medicine, Ajou University Hospital, Suwon, Korea
  4. 4Department of Anesthesiology and Pain Medicine, Seoul National University College of Medicine, Seoul, Korea
  5. 5Center for Regional Anesthesia and Pain Medicine, Wan Fang Hospital, Taipei Medical University, Taipei, Taiwan
  1. Correspondence to Professor Jin-Tae Kim, Seoul National University Hospital, Jongno-gu 03080, Korea; jintae73{at}


Background Dexmedetomidine sedation has advantages, such as low incidence of respiratory depression and prolonged block duration, but also significant disadvantages, such as slow onset, high rate of sedation failure, and a long context-sensitive half-life. Remimazolam provides rapid sedation and recovery, high sedation efficacy and has minimal hemodynamic effects. We hypothesized that patients who received remimazolam would require less rescue midazolam than dexmedetomidine.

Methods Patients (n=103) scheduled for surgery under spinal anesthesia were randomized to receive dexmedetomidine (DEX group) or remimazolam (RMZ group) targeting a Modified Observer’s Assessment of Alertness/Sedation score of 3 or 4. Rescue midazolam was administered if the patient failed to be sedated after the initial loading dose or despite infusion rate adjustment.

Results Rescue midazolam administration was significantly higher in the DEX group (0% vs 39.2%; p<0.001). Patients in the RMZ group reached the target sedation level more rapidly. The incidences of bradycardia (0% vs 25.5%; p<0.001) and hypertension (0% vs 21.6%; p<0.001) were higher in the DEX group. Respiratory depression occurred at a higher rate in the RMZ group (21.2% vs 2.0%; p=0.002), but no patients required manual ventilation. Patients in the RMZ group recovered faster, had a shorter PACU stay and higher satisfaction scores. Hypotensive episodes in the PACU were more frequent in the DEX group (1.9% vs 29.4%; p<0.001).

Conclusions Remimazolam showed excellent sedation efficacy, minimal hemodynamic effects, and fewer adverse events in the PACU than dexmedetomidine. However, it is important to note that respiratory depression was more frequent with the use of remimazolam.

Trial registration number NCT05447507.

  • Lower Extremity
  • Drug-Related Side Effects and Adverse Reactions

Data availability statement

Data are available on reasonable request.

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Data availability statement

Data are available on reasonable request.

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  • Contributors HK: conceptualization, methodology, software, validation, formal analysis, investigation, data curation, wtiring—original draft, visualization; YK: methodology, validation, investigation; JB: methodology, validation, investigation; SY: methodology, validation, investigation, visualization; Y-JL: methodology, validation, investigation; J-TK: guarantor, conceptualization, methodology, funding acquisition, project administration, supervision, writing—review and editing.

  • Funding Support was provided from Hana Pharm.

  • Competing interests None declared.

  • Provenance and peer review Not commissioned; externally peer reviewed.

  • Supplemental material This content has been supplied by the author(s). It has not been vetted by BMJ Publishing Group Limited (BMJ) and may not have been peer-reviewed. Any opinions or recommendations discussed are solely those of the author(s) and are not endorsed by BMJ. BMJ disclaims all liability and responsibility arising from any reliance placed on the content. Where the content includes any translated material, BMJ does not warrant the accuracy and reliability of the translations (including but not limited to local regulations, clinical guidelines, terminology, drug names and drug dosages), and is not responsible for any error and/or omissions arising from translation and adaptation or otherwise.