Ultrasound-guided Nerve Block: Determination of the Minimal Effective Volume of Local Anesthetic

Study Overview
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Brief Summary
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Ultrasound guidance can reduce the required local anesthetic volume for successful peripheral nerve block. The aim of the study is to determine the minimum volume of local anesthetic to achieve an ultrasound-guided median nerve block with a dextrose 5% hydrodissection approach.

Official Title
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Ultrasound-guided Median Nerve Block With Dextrose 5% Hydrodissection: Determination of the Minimal Effective Volume of Local Anesthetic

Conditions
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Surgery

Intervention / Treatment
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* Procedure: median nerve block


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: aged 18 years from 18 to 80 years with an ASA (American Society of Anesthesiologists) physical status I-II elective hand ambulatory surgery with a maximum duration of 30 minutes involving the median nerve and performed with elbow nerve blocks Exclusion Criteria: pregnant or lactating women, contra-indication to regional anesthesia diabetes mellitus, effective anticoagulation or antiplatelet therapy, laboratory evidence of abnormal bleeding neurological disease ( including carpal tunnel syndrome or neuromuscular disease detected by preoperative neurological examination in the median nerve) infection at the puncture site contra-indication to the administration of lidocaine, notably allergy contra-indication to the administration of lidocaine with epinephrine not speaking French Exclusion from the study: patient having an intraneural injection of the median nerve defined by swelling appearance are excluded from analysis

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 80 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Treatment
Allocation: Randomized
Intervention Model: Parallel Assignment
Interventional Model Description: Ascending dose model
Masking: Triple


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: median nerve block<br>An ultrasound-guided nerve block with dextrose 5% hydrodissection is performed in each case. The first patient will receive a 2 mL local anesthetic solution. For following patients, the volume of local anesthetic depends on the clinical result of the previous patient: increase of the volume (0.5 mL) in case of failure, no change or decrease (0.5 mol) in case of success; a randomization is made in this case (BCD method, Stylianou M, Flournoy N. Dose finding using the biased coin up-and-down design and isotonic regression. Biometrics 2002;58:171-7) | Procedure: median nerve block<br> <br> * Other names: lidocaine with epinephrine (20 mg/ml);|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Minimal effective volume of local anesthetic | Effective volume of local anesthetic to obtain a successful median nerve block block in 95% of patients defined as complete light touch block at the palmar aspect of the 2 distal phalanges of the index finger during a 30 minute evaluation period (mL) | 1 hour | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Nerve block onset time | Onset time for complete cold light touch and motor block at 30 min and 45 min. | 1 hour | 
| Success rate of the median nerve block | Success rate concerns: success rate of sensitive block: complete cold and light touch block at 30 min and 45 min at the palmar aspect of the 2 distal phalanges of the index finger and on the thenar eminence success rate of motor block: complete motor block at 30 min and 45 min | 1 hour | 
| Additional local anesthetic | Percentage of cases where additional local anesthetic was necessary before the incision (%), i.e; performed by anesthesiologist Percentage of cases where additional local anesthetic was necessary after the incision (%), i.e; performed by surgeon | 2 hours | 
| Duration of analgesia | Time to first analgesic requirement (minutes) | 1 day | 
| Duration of the block | Delay between the completion of the block and the returned to normal onset of sensory and motor recovery of the first three fingers of the hand) (minutes) | 1 day | 
| Complications | complications occurring during the procedure (pain, paresthesia, intraneural injection and vascular puncture), complications noticed at the first postoperative month (residual pain, paresthesia, dysesthesia, weakness) | 1 month | 
| Block procedure time | Time taken to perform hydrodissection with dextrose 5% and inject the local anesthetic (min) | One hour |