Regional versus systemic dexmedetomidine as an adjuvant to lidocaine for intravenous regional anaesthesia in healthy volunteers: a randomized crossover study

Abstract

Background

Dexmedetomidine enhances the quality and duration of lidocaine intravenous regional anaesthesia (IVRA). However, the two administration routes have not been directly compared regarding effects on tourniquet tolerance time with lidocaine IVRA. Additionally, it remains unclear whether the prolonged tourniquet tolerance stems from the direct peripheral action of dexmedetomidine or indirect systemic analgesic effects.

Methods

We conducted forearm IVRA in 12 healthy volunteers using a crossover design on two separate study days. One day, the systemic dexmedetomidine group received an intravenous infusion of 0.5 μg/kg dexmedetomidine (20 mL) in one arm, followed by 0.5% lidocaine (25 mL) forearm IVRA in the contralateral arm. On the other day, the regional dexmedetomidine group received an intravenous 0.9% saline infusion (20 mL) in one arm, followed by combined 0.5% lidocaine (25 mL) and 0.5 μg/kg dexmedetomidine forearm IVRA in the opposite arm. After a two-week washout period, participants crossed over to receive the alternate treatment. The primary outcome was tourniquet tolerance time, from initiating IVRA until the patient-reported tourniquet pain numerical rating scale exceeded three.

Results

The tourniquet tolerance time was longer with regional versus systemic dexmedetomidine (36.9 ± 7.6 min vs 23.3 ± 6.2 min, respectively), with a 13.6 min mean difference (95% CI: 10.8 to 16.4 min, p < 0.001). Regional dexmedetomidine also hastened sensory onset and extended sensory recovery compared to systemic administration. Delayed sedation after tourniquet release occurred in 5 of 12 subjects receiving regional dexmedetomidine.

Conclusion

The addition of regional dexmedetomidine to lidocaine prolonged tourniquet tolerance time in forearm IVRA to a greater extent compared to systemic dexmedetomidine in healthy volunteers.

Trial registration

Chinese Clinical Trial Registry, ChiCTR2300067978.

KEY MESSAGES

• The addition of regional dexmedetomidine prolongs tourniquet tolerance time with lidocaine forearm IVRA.

• Regional dexmedetomidine accelerates sensory block onset time and extends sensory block recovery time when supplemented with lidocaine forearm IVRA.

• Delayed sedative effects following tourniquet release were witnessed in some participants administered regional dexmedetomidine.

GRAPHICAL ABSTRACT

Keywords:

• Crossover study
• dexmedetomidine
• intravenous regional anesthesia
• lidocaine

Acknowledgments

This study was supported by the Natural Science Foundation of Fujian Province (No. 2021J01378) and the Medical Innovation Project of Fujian Province (No. 2022CXA007).

Author contributions statement

Xincheng Liao: Conceptualization, Design, Investigation. Jie Lin: Conceptualization, Investigation, Writing-original draft. Xinru Shu: Investigation, Writing-original draft. Shisen Hong: Investigation, Data curation, Software. Yusheng Yao: Conceptualization, Design, Investigation, Funding acquisition, Supervision, Writing-review & editing. Hao Li: Conceptualization, Investigation, Resources, Validation. All authors read and gave final approval of the version to be published.

Disclosure statement

No potential conflict of interest was reported by the author(s). Figure 1 was created using Figdraw (www.figdraw.com).

Data availability statement

The data and materials supporting the results or analyses presented in this paper are available upon reasonable request.

Correction Statement

This article has been corrected with minor changes. These changes do not impact the academic content of the article.

Additional information

Funding

This study was supported by the Natural Science Foundation of Fujian Province (No. 2021J01378) and the Medical Innovation Project of Fujian Province (No. 2022CXA007).