Effect of Dexamethasone and Epinephrine on the Duration of Sciatic Nerve Blocks With Ropivacaine

Study Overview
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Brief Summary
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The aim of the present study is to test that adding dexamethasone or epinephrine significantly prolongs the duration of sciatic nerve blocks with ropivacaine and that the magnitude of the effect differs among dexamethasone and epinehrine.

Detailed Description
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In a double-blinded trial utilizing single-injection sciatic nerve block, patients are randomly assigned to one of three groups: control: 0.5% ropivacaine adding normal saline; epinephrine: 0.5% ropivacaine adding epinephrine; dexamethasone: 0.5% ropivacaine adding dexamethasone. We assess time to first analgesic request after post-anaesthesia care unit discharge.

Official Title
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Effect of Dexamethasone and Epinephrine on the Duration of Sciatic Nerve Blocks With Ropivacaine in Ankle and Foot Surgery

Conditions
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Postoperative Pain

Intervention / Treatment
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* Drug: Dexamethasone
* Drug: Epinephrine


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: American Society of Anesthesiologists physical status I and II patients undergoing elective hallux valgus repair Exclusion Criteria: patients receiving chronic analgesic therapy diabetes peripheral neuropathies psychiatric disorders hypersensitivity to amide local anesthetics renal disorders

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 75 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: Triple


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Dexamethasone<br>Dexamethasone 8 mg is added to 0.5% ropivacaine 20 ml for sciatic nerve block. | Drug: Dexamethasone<br>* In dexamethasone group, dexamethasone 8 mg is added to 0.5% ropivacaine 20 ml for sciatic nerve block.<br>|
| Placebo Comparator: Control<br>Normal saline 1 ml is added to 0.5% ropivacaine 20 ml for sciatic nerve block. | |
| Experimental: epinephrine<br>Epinephrine 1:200,000 is added to 0.5% ropivacaine 20 ml for sciatic nerve block. | Drug: Epinephrine<br>* Epinephrine 1:200,000 is added to 0.5% ropivacaine 20 ml for sciatic nerve block<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| time to first analgesic request after postanesthetic care unit discharge | A blinded observer interview patients at arrival in postanesthetic care unit, 6 hour, 24 hour, 48 hour, 72 hour after operation. | from arrival in postanesthetic care unit to 72 hours after operation | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| time of recovery of motor and sensory functions on the operated foot | The time of recovery of motor (ability to move the ankle) and sensory (recovery of normal pinprick sensation) functions on the operated foot is recorded by the blinded observer at arrival in postanesthetic care unit, 6 hour, 24 hour, 48 hour, 72 hour after operation. | from arrival in postanesthetic care unit to 72 hours after operation |