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

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

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

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.

The study will be conducted as a prospective, randomized, double blinded, parallel trial at the University of Pittsburgh Medical Center (UPMC) Shadyside Hospital.

Randomization will be performed with software excel or spss. This randomization will be kept in an envelope. After the patient consents participation in the study, the investigator and the care provider will open the envelope and will perform the block according to the established in the randomization. The patient or the outcomes assessor will not have access to the volume and concentration used during the block. Will be the responsibility of investigators to keep in a safe place the information about the block received by the patients.

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

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

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.

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

Murouchi T, Iwasaki S, Yamakage M. Quadratus Lumborum Block: Analgesic Effects and Chronological Ropivacaine Concentrations After Laparoscopic Surgery. Reg Anesth Pain Med. 2016 Mar-Apr;41(2):146-50. doi: 10.1097/AAP.0000000000000349.