Volume vs Concentration: Quadratus Lumborum Blocks With High Volume/Low Concentration or Low Volume/ High Concentration in Nephrectomies

Study Overview
=================
Brief Summary
-----------------
The quadratus lumborum has since 2016 become standard of care for abdominal and retroperitoneal surgeries at UPMC-Shadyside Hospital, replacing paravertebral blocks, and as part of a broader multimodal analgesia institutional Enhanced Recovery After surgery protocol. Since the first description of this technique, several approaches to and anatomic targets within the quadratus lumborum plane have been described although their mechanism of action, spread, and relative clinical effectiveness remain areas of some debate. What is proposed here is to investigate the relative clinical effectiveness of the relationship high volume/low concentration of local anesthetic or low volume/ high concentration of local anesthetic.

Official Title
-----------------
Volume Versus Concentration: a Prospective, Double Blind, Parallel Study to Compare the Clinical Effectiveness of Bilateral Quadratus Lumborum Blocks Using High Volume/Low Concentration or Low Volume/ High Concentration Local Anesthetic in Nephrectomies

Conditions
-----------------
Analgesia, Postoperative Pain, Block

Intervention / Treatment
-----------------
* Drug: Ropivacaine 0.5% Injectable Solution


Participation Criteria
=================
Eligibility Criteria
-----------------
Inclusion Criteria: Patients 18-90 years old Patients undergoing nephrectomy Body Mass Index 19-36 Male and Female All races American Society of Anesthesiologist scale I, II, III Exclusion Criteria: Patient refusal Pregnancy Non-English speaking or inability to participate in the study Patients with coagulopathy or With International Normalized Ratio >1,5 the day of the surgery. Chronic steroid use Chronic pain Chronic opiate use

Ages Eligible for Study
-----------------
Minimum Age: 18 Years
Maximum Age: 90 Years

Sexes Eligible for Study
-----------------
All

Accepts Healthy Volunteers
-----------------
No

Study Plan
=================
How is the study designed?
-----------------

Design Details

Primary Purpose: Treatment
Allocation: Randomized
Intervention Model: Parallel Assignment
Interventional Model Description: The study will be conducted as a prospective, randomized, double blinded, parallel trial at the University of Pittsburgh Medical Center (UPMC) Shadyside Hospital.
Masking: Double


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: low volume High concentration group<br>1.Low Volume: 30 subjects randomized to Low Volume will receive bilateral Quadratus lumborum Block II. Each block of 0,75% ropivacaine x 15 mL + dexmedetomidine 0.4 mcg/kg (max dose 30 mcg for age <70, max dose 20 mcg for age >70) + dexamethasone 4 mg | Drug: Ropivacaine 0.5% Injectable Solution<br>* There will be two groups, in order to compare two different sets of volumes with the same amount of drug. we will try to identify if it is better one volume over the other in terms of pain control and consume of opioids, as well the presence or absence of motor weakness.<br>|
| Experimental: high volume low concentration<br>2.High Volume: 30 subjects randomized to High Volume will receive bilateral Quadratus lumborum Block II. Each block of 0,375% ropivacaine x 30 mL + dexmedetomidine 0.4 mcg/kg (max dose 30 mcg for age <70, max dose 20 mcg for age >70) + dexamethasone 4 mg | Drug: Ropivacaine 0.5% Injectable Solution<br>* There will be two groups, in order to compare two different sets of volumes with the same amount of drug. we will try to identify if it is better one volume over the other in terms of pain control and consume of opioids, as well the presence or absence of motor weakness.<br>|

What is the study measuring?
-----------------
Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| pain control over the next 72 hours after surgery: Visual analogue scale | Visual analogue scale (0-10) measurement | 72 hours | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| opioid consumption during the first 72 hours | opioid consumption in morphine milliequivalents during the first 72 hours | 72 hours | 
| time of the first opioid consumption after surgery | time after surgery that patient takes to require opioid medication after surgery | 24 hours | 
| 100 feet walking | time after surgery that the patient takes in order to be able to walk 100 feet | 48 hours | 
| presence or absence of muscular weakness after Quadratus lumborum type 2 block | muscular weakness is associated sometime with femoral quadratus muscle weakness | 24 hours |