A randomized trial to determine the minimum effective lidocaine volume for median nerve block using hydrodissection

Eric Dufour,Alexandre Vallée,Marie Alice Novillo,Marc Fischler,Lila Aubert,Anne Chambon,Rainer Kutz,Souhail Jaziri

doi:10.1038/s41598-021-03660-7

Eric Dufour, Alexandre Vallée + Show 6 more

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https://doi.org/10.1038/s41598-021-03660-7

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Abstract

Ultrasound-guided hydrodissection with 5% dextrose in water (DW5) creates a peri-nervous compartment, separating the nerve from the neighboring anatomical structures. The aim of this randomized study was to determine the minimum volume of lidocaine 2% with epinephrine 1:200,000 required when using this technique to achieve an effective median nerve block at the elbow in 95% of patients (MEAV95). Fifty-two patients scheduled for elective hand surgery received an ultrasound-guided circumferential perineural injection of 4 ml DW5 and an injection of local anesthetic (LA) following a biased coin up-and-down sequential allocation method. A successful block was defined as a light touch completely suppressed on the two distal phalanges of the index finger within a 30-min evaluation period. The MEAV95 of lidocaine 2% with epinephrine was 4 ml [IQR 3.5–4.0]. Successful median nerve block was obtained in 38 cases (82.6%) with median onset time of 20.0 [10.0–21.2] minutes (95% CI 15–20). The analgesia duration was 248 [208–286] minutes (95% CI 222–276). Using an ultrasound-guided hydrodissection technique with DW5, the MEAV95 to block the median nerve at the elbow with 2% lidocaine with epinephrine was 4 ml [IQR 3.5–4.0]. This volume is close to that usually recommended in clinical practice.Trial registration clinicaltrials.gov. NCT02438657, Date of registration: May 8, 2015.

Highlights

Ultrasound-guided hydrodissection with 5% dextrose in water (DW5) creates a peri-nervous compartment, separating the nerve from the neighboring anatomical structures
A few studies have evaluated the volume-response relationship of local anesthetic (LA) for peripheral nerve blocks[3,4,5]. The reproducibility of these studies for everyday clinical practice remains in question, suggesting that the manipulation of small aliquots and further needle repositioning for consecutive injections are not straightforward and require a high level of expertise to interpret a correct distribution around the nerve and detect an intraneural injection[4,5,6]
As an increase in cross-sectional area (CSA) is a clue for intraneural injection, we considered an extraneural compartment to be created when the needle passed through multiple sequential layers and the nerve did not swell during DW5 injection

Summary

Introduction

Ultrasound-guided hydrodissection with 5% dextrose in water (DW5) creates a peri-nervous compartment, separating the nerve from the neighboring anatomical structures The aim of this randomized study was to determine the minimum volume of lidocaine 2% with epinephrine 1:200,000 required when using this technique to achieve an effective median nerve block at the elbow in 95% of patients (MEAV95). The reproducibility of these studies for everyday clinical practice remains in question, suggesting that the manipulation of small aliquots and further needle repositioning for consecutive injections are not straightforward and require a high level of expertise to interpret a correct distribution around the nerve and detect an intraneural injection[4,5,6] The latter is important since it has been clearly reported that intraneural injections, whether intended or unintended, significantly reduce the LA dose and improve the success rate to achieve an effective b lock[7,8,9]. The present study aimed to evaluate, using a hydrodissection technique with DW5, the minimum volume of lidocaine 2% with epinephrine 1:200,000 required for an effective ultrasound-guided median nerve block at the elbow in 95% of patients (MEAV95)

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