Effect of Local Anesthetic Dose on Interscalene Block

Study Overview
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Brief Summary
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The purpose of this study is to determine if a decrease in the standard volume of local anesthetic used to numb your shoulder area before shoulder arthroscopy will provide adequate anesthesia for the procedure and decrease the amount of time until you are ready for discharge from the hospital.

Detailed Description
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Traditionally, an interscalene block is done either with nerve stimulator or ultrasound guided using 40-60mL of local anesthetic. The study plans to investigate the difference in hand grip strength post-operatively in patients who will receive interscalene blocks with 40mL versus a lower dose (20mL) of local anesthetic. We suspect the lower dose will achieve adequate surgical anesthesia while creating less motor block and thus, increase patient satisfaction, present fewer complications or adverse affects and decrease time in the recovery room.

Official Title
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Effect of Local Anesthetic Dose on Interscalene Block for Shoulder Arthroscopy, Patient Satisfaction and Return of Handgrip Strength

Conditions
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Shoulder Arthroscopy, Interscalene Block

Intervention / Treatment
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* Procedure: Low Dose (20 ml) Local Anesthetic Volume for Interscalene Block
* Procedure: Control Dose (40 mL) Local Anesthetic Volume for Interscalene Block
* Drug: Low Dose (20 mL) Local Anesthetic (Mepivacaine:Bupivacaine)
* Drug: Control Dose (40 mL) Local Anesthetic (Mepivacaine:Bupivacaine)


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Age: 18 - 80 years old Surgical time < 2.5 hours ASA I, II or III Shoulder arthroscopy Exclusion Criteria: Age < 18 or > 80 years old Chronic pain patients (on narcotics/opioids > 3 months) Open shoulder surgical procedure BMI > 40 Pre-existing neurological condition Patient refusal of interscalene block Severe respiratory disease or hemidiaphragmatic dysfunction Allergy to any local anesthetics Planned general anesthesia

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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Accepts Healthy Volunteers

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: Low Dose (20 mL) Local Anesthetic<br>Intervention to be administered is a total volume of 20 mL local anesthetic containing a 1:1 mixture of 1.5% Mepivacaine: 0.5% Bupivacaine. | Procedure: Low Dose (20 ml) Local Anesthetic Volume for Interscalene Block<br>* Anesthetic volume: Investigational group: A 1:1 Mepivacaine 1.5%: Bupivacaine 0.5% mixture for a total of 20 mL<br>Drug: Low Dose (20 mL) Local Anesthetic (Mepivacaine:Bupivacaine)<br> <br> * Other names: Bupivacaine;|
| Active Comparator: Control Dose (40 mL) Local Anesthetic<br>Intervention to be administered is a total volume of 40 mL local anesthetic containing a 1:1 mixture of 1.5% Mepivacaine: 0.5% Bupivacaine | Procedure: Control Dose (40 mL) Local Anesthetic Volume for Interscalene Block<br>* Anesthetic volume: Control group: A 1:1 Mepivacaine 1.5%: Bupivacaine 0.5% mixture for a total of 40 mL<br>Drug: Control Dose (40 mL) Local Anesthetic (Mepivacaine:Bupivacaine)<br> <br> * Other names: Bupivacaine;|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Handgrip Strength | The primary outcome will be handgrip strength as measured by a dynamometer. A reading will be obtained at baseline (before the interscalene block) and 60 minutes post-operative. | Difference between between baseline and postoperative. | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Patient Readiness to Discharge |  | Participants will be followed every 15 minutes post-surgery until discharged from the hospital (up to 180 minutes) | 
| Duration of Analgesia | Time to pain | Postoperative Day 2 | 
| Side Effects | Incidence of nausea | Postoperative Day 2 | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Interscalene Block