Influence of Ultrasonographic Hydro-dissection With Glucose 5% on Nerve Block Efficiency

Study Overview
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Brief Summary
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The real-time visualization of a needle and nerve during an ultrasound-guided nerve block can be challenging. These difficulties may partly explain the systemic complications of local anesthetics under ultrasound. Injection of small amounts of a solution around the anesthetized nerve (hydro-dissection) has been proposed to enhance contrast outlining its borders and also to improve the visualization of the needle tip. The glucose solution 5% solution is interesting because it allows, unlike saline, to maintain the motor response with neurostimulation. The hydro-dissection can be particularly useful when one suspect hypoechoic vessels near the nerve to be anesthetized. Thereby, the nerve well demarcated and separated from the vessels, injection of local anesthetic is performed in the circumferential diffusion space (like a small pocket) without redirecting needle. The influence of this hydro-dissection on the nerve block efficiency is unknown. The nerve block quality can be improved because the entire anesthetic is injected in contact with the nerve, but it can also be reduced due to the dilution of the local anesthetic by the glucose solution. In this randomized study, the investigators test the hypothesis that hydro-dissection does not alter the nerve block onset time.

Official Title
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Influence of Ultrasonographic Hydro-dissection With Glucose 5% Solution on Median Nerve Block Efficiency: a Prospective and Randomized Study

Conditions
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Nerve Block

Intervention / Treatment
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* Procedure: median nerve block
* Procedure: median nerve block after hydro-dissection


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Adult patients with an ASA physical status I-II scheduled for elective ambulatory surgery of the hand or wrist involving the median nerve Exclusion Criteria: Patients with type 1 or 2 diabetes mellitus, History of clinical or laboratory evidence of abnormal bleeding, Infection at the injection site, Allergy to local anesthetic, Preexisting central or peripheral muscular or neurological disease (for example: carpal tunnel syndrome)

Ages Eligible for Study
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Minimum Age: 18 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
Masking: Quadruple


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Active Comparator: nerve block<br>median nerve block (6 ml lidocaine 1.5 % with adrenalin 1:200000) | Procedure: median nerve block<br>* median nerve block performed using ultrasound guidance<br>|
| Experimental: median nerve block after hydro-dissection<br>median nerve block (6 ml lidocaine 1.5 % with adrenalin 1:200000) after hydro-dissection (glucose 5% solution) | Procedure: median nerve block after hydro-dissection<br>* median nerve block performed after hydro-dissection (glucose 5% solution), both using ultrasound guidance<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Onset time of sensory blockade (light touch test: total loss of sensation at the two distal phalanges of index) |  | 30 minutes after injection | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Onset time of sensory blockade (cold test at index finger and thenar eminence) |  | 30 minutes after injection | 
| Onset time (light touch test at thenar eminence) |  | 30 minutes after injection | 
| Onset time for motor blockade |  | 30 minutes after injection | 
| Success rate (% of patients with total light touch block at index finger within 30 min evaluation period) |  | 30 minutes after injection | 
| Successful surgical anesthesia |  | 30 minutes after injection | 
| Duration of nerve blockade |  | 12 hours | 
| Nerve block complication |  | one month | 
| Duration of the puncture procedure |  | 30 minutes after the beginning of the procedure |