Minimum Effective Concentration of Ropivacaine for Brachial Plexus Block Via the Supraclavicular and Infraclavicular Approach, Femoral Nerve Block, Sciatic Nerve Block Via the Popliteal and Parasacral Approach

Study Overview
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Brief Summary
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This is a dose finding study to identify the minimum effective anesthetic concentration (MEAC) of ropivacaine to produce insensate body parts sufficient for surgery in supraclavicular and infraclavicular approaches to the brachial plexus, parasacral and popliteal approaches to the sciatic nerve, femoral nerve and transversus abdominis plane (TAP) blocks in adults.

Official Title
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Minimum Effective Anesthetic Concentration of Supraclavicular Block, Infraclavicular Block, Femoral Nerve Block and Sciatic Nerve Block Via the Popliteal and Parasacral Approach

Conditions
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Surgical Anesthesia

Intervention / Treatment
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* Drug: Ropivacaine concentration


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: American Society of Anesthesiologists physical status I to III (patients may be healthy or have systemic disease, but any disease does not pose a constant threat to life, and patients are neither moribund, nor not expected to survive without the operation). Age 18 or above Undergoing elective ambulatory surgery of the upper limb (excluding the shoulder), lower limb (excluding the hip), or lower abdomen with sensory blockade as part of the pain management plan. Exclusion Criteria: Body mass index of >35 kg/m2 (higher chance of failure) Deformities of the leg (for patients in the parasacral, femoral, and popliteal groups), or the chest or shoulder (for patients in the supraclavicular, infraclavicular, and TAP groups) Preexisting infection at the injection site Existing neurologic disease Allergy to local anesthetic agents Severe respiratory disease Coagulopathy Any other contraindication to the block being considered Patients requiring total motor blockade as well as sensory blockade

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

Intervention Model: Single Group Assignment
Masking: Triple


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Ropivacaine<br>Sequential allocation of ropivacaine concentration depending on the success or failure of surgical anesthesia of the previous patient | Drug: Ropivacaine concentration<br>* Single shot preoperative perineural injection of ropivacaine to achieve surgical anesthesia. The concentration of ropivacaine is lowered by 0.05% after every successful surgical anesthesia specific to that block and raised by 0.05% after every unsuccessful surgical anesthesia specific to that block<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Effective Concentration of Ropivacaine to Produce Surgical Anesthesia in 50% of Population | The concentration of ropivacaine for each patient's nerve-block injection was determined per protocol. | 1 day | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Number of Patients With Complications | All patients were followed up for complications such as bleeding, infection, side effects, nerve damage | 3 days |