Nerve Block Technique Reduces Opioid Use After Cardiac Surgery

Opioid exposure after open-heart surgery is associated with delirium, nausea, and other complications, and may contribute to longer-term dependence. Because cardiac procedures often still require high intraoperative opioid dosing, care teams continue to seek safer approaches to postoperative pain control. These concerns are amplified by ongoing opioid-related mortality. A new randomized trial shows that targeted parasternal nerve blocks can substantially reduce opioid requirements after cardiac surgery.

The multicenter EPOCH-CardioLink-10 trial, led by St. Michael’s Hospital (Toronto, Canada), enrolled 318 adults undergoing median sternotomy across hospitals in four Canadian provinces between 2023 and 2025. All participants had their breastbone divided and wired closed as part of standard care. The study compared continuous nerve blocks infusing local anesthetic with a placebo approach during the first two postoperative days.

Investigators used a superficial parasternal intercostal plane block to deliver local anesthetic alongside the sternum. Catheters were threaded on each side of the chest with the patient lying supine after wound closure. Continuous ropivacaine infusion then targeted the intercostal nerves that transmit pain from the sternal region, aiming to blunt early postoperative nociception without systemic opioid escalation.

Within the first 72 hours, patients receiving ropivacaine used an average of 20.7 fewer morphine milligram equivalents (MME) compared with placebo. They were also nearly half as likely to require very high opioid doses, with 12.9% reaching at least 200 MME versus 23% in the placebo group. Findings were published earlier this month in The Lancet Regional Health - Americas.

The trial addresses a persistent gap in cardiac anesthesia, where opioid-sparing strategies have lagged because anesthetic gases can depress blood pressure intraoperatively. Enhanced Recovery After Surgery guidelines already encourage reducing opioids and using alternatives such as nerve blocks, while calling for high-quality evidence to shift practice. With more than two million sternotomy procedures performed globally each year, evidence from this trial proposes a feasible postoperative pathway that hospitals can adopt to limit opioid exposure.

“We often see patients who started opioids after a major surgery or trauma, and years later, they're still relying on them to manage chronic pain. What begins as appropriate pain treatment can evolve into long-term use that's very challenging to reverse,” said Ahmad Alli, medical director of the Cardiovascular ICU at St. Michael's Hospital.

“Opioid addiction can begin with a prescription. EPOCH-CardioLink-10 is our effort to make that first prescription smaller, smarter and safer after cardiac surgery,” said Subodh Verma, cardiac surgeon-scientist at St. Michael's Hospital.

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