Effects of Continuous Bilateral QL Analgesia After Open Abdominal Surgery

The Effects of Continuous Bilateral Quadratus Lumborum Analgesia on Pain, Opioid Consumption, and Opioid-related Complications After Open Abdominal Surgery: A Randomized Controlled Trial

Eligible patients will be randomized 1:1 without stratification to bilateral continuous QL catheters with local anesthetic continuous infusion (QL block + IV patient-controlled analgesia group) or normal saline continuous infusion (IV patient-controlled analgesia group). In the postanesthesia care unit (PACU), patients will be given intravenous boluses of hydromorphone or fentanyl as needed. Following immediate recovery from anesthesia, patients will be provided with a hydromorphone IV patient-controlled analgesia pump with standard initial settings and an option of clinician dose for breakthrough pain. IV patient-controlled hydromorphone pump settings will be titrated to comfort level (pain score<4) by blinded clinicians. Each of the catheters will be connected to patient controlled infusion pump running at a basal rate of 6mL/hour of 0.1% Bupivacaine or normal saline with on-demand bolus of 5 mL every 60 minutes to be started in the operating room before the surgical incision. Opioid consumption first 72 hours or until discharge, whichever comes first will be recorded. Pain scores during first 72 hours or until discharge, whichever comes first will be recorded with a verbal rating scale and obtained from the patient's electronic medical records. The morning of post operative day 1 and post operative day 3 the ORSDS and QOR surveys will be completed. Morning of the day of discharge, the overall patient satisfaction with pain management survey will be completed.

local anesthetic continuous infusion (QL block + IV PCA group) or normal saline continuous infusion (IV PCA group).

Bilateral QL catheter with local anesthetic infusion + intravenous patient controlled narcotic medication

Bilateral QL catheter with normal saline infusion + intravenous patient controlled narcotic medication

primary hypothesis is that bilateral continuous QL local anesthetic infusion with IV PCA reduces total opioid consumption and/or time-weighted average pain scores during 72 hours after surgery compared to patients under IV PCA alone, and not worse on either outcome. In other words, IV PCA + QL block is superior to IV PCA alone, resulting in lower opioid consumption and/or less pain and not worse on either outcome.

primary hypothesis is that bilateral continuous QL local anesthetic infusion with IV PCA reduces total opioid consumption and/or time-weighted average pain scores during 72 hours after surgery compared to patients under IV PCA alone, and not worse on either outcome.

Inclusion Criteria: Adults scheduled for elective colorectal surgery with a midline incision; American Society of Anesthesiologists (ASA) physical status 1-3. Exclusion Criteria: Contraindication or intolerance to opioids and/or local anesthetics; Inability to use IV PCA system; History of chronic pain defined as use of opioids for more than 30 consecutive days within the 3 preoperative months at the dose equal or greater than equivalent of 15 mg of morphine and/or abdominal pain for more than 6 months, present most days of the weeks; History of neurological illness and/or neuropathy - Peripheral neuropathy, paralysis; Pregnancy and/or breastfeeding; Chronic renal failure, defined by estimated GFR <60 ml/min; Chronic liver failure, defined by cirrhosis, portal hypertension, or history of variceal bleeding. BMI > 35