Erector spinae plane block for minimally invasive mitral valve surgery: a double-blind, prospective, randomised placebo-controlled trial-a study protocol

Introduction: In the context of enhanced recovery after cardiac surgery, surgical techniques for mitral valve surgery have witnessed substantial modifications, from approaching the heart using open approaches with traditional sternotomy to thoracoscopic access via minithoracotomy. After cardiac surgery, acute postoperative pain is frequent and caused by surgical incision and retraction. Perioperative analgesia in cardiac surgery still relies mainly on opioids. Although neuraxial techniques could be a valuable non-opioid-based analgesia regimen, they can be associated with devastating complications in situations with (iatrogenic) coagulation abnormalities. Only two randomised clinical trials describe the erector spinae plane (ESP) block to provide sufficient postoperative analgesia following cardiac surgery with median sternotomy. Regarding postoperative analgesia after cardiac surgery with a minithoracotomy approach, adequately designed trials are still lacking. We, therefore, designed a double-blind, placebo-controlled trial to prove the hypothesis that the ESP block reduces opioid consumption in patients undergoing minimally invasive mitral valve surgery (MIMVS).

Methods and analysis: Sixty-four patients undergoing MIMVS will be included in this double-blind, prospective, placebo-controlled trial. Patients will be randomised to receive an ESP block with a catheter with either intermittent ropivacaine 0.5% (ropi group) or normal saline 0.9% (placebo group). Both groups will receive patient-controlled intravenous analgesia with morphine following extubation. Primary endpoint is the 24-hour cumulative morphine consumption after extubation. Multiple secondary endpoints will be evaluated.

Ethics and dissemination: The study is approved by the ethics committee of the University Hospitals Leuven, the Clinical Trials Centre of the University Hospitals Leuven and the 'Federaal Agentschap voor Geneesmiddelen en Gezondheidsproducten'. Dissemination of the study results will be via scientific papers.

Trial registration number: EudraCT identifier: 2019-001125-27.