Study on Optimal Temperature During Cardiopulmonary Bypass (THERMIC-4)

In order to perform heart surgery, a machine called cardiopulmonary bypass (CPB), or more commonly known as a heart-lung machine, is used to maintain the circulation of oxygenated blood needed by the rest of the body and its organs. Historically, when a patient is connected to CPB, their body is cooled below the normal body temperature. This is known as hypothermia. This is because scientific studies have previously shown that reduced body temperature lowers metabolism and therefore offers more protection to the brain and other organs due to the reduced oxygen requirement. The evidence supporting this practice, however, has been challenged throughout the history of cardiac surgery, with studies supporting that normothermia, or normal body temperature, is a safe alternative. Despite this, the practice of hypothermia has persisted. Published data from a survey of 139 cardiac surgeons in the United Kingdom showed that 84% still routinely employ hypothermic CPB during surgery. To assess whether normothermic or hypothermic CPB is safer, a clinical trial requiring a large sample size and high recruitment rates will be required. Therefore, the investigators aim to assess firstly the feasibility of trial recruitment and allocation adherence in this study. 100 adults across 10 different cardiac surgery centres in the United Kingdom will be recruited to a multicentre feasibility randomised controlled trial comparing normothermia (active comparator) against hypothermia (control comparator) during cardiopulmonary bypass in cardiac surgery. This study will also test the ability of the Cardiothoracic Interdisciplinary Research Network (CIRN), a trainee-led research collaborative, to collect pilot data on Major Adverse Cardiac and Cerebrovascular Events (MACCE) using a regulation-approved electronic application HealthBitⓇ. Participants will also be asked to complete quality of life surveys. The results of this study will subsequently inform a large, adequately powered randomised controlled trial for optimal temperature management during CPB.

NCT Number	NCT05996120
Lead Sponsor	University of Leicester Collaborators: NHS National Waiting Times Centre Board, Sheffield Teaching Hospitals NHS Foundation Trust, Oxford University Hospitals NHS Trust, Hull University Teaching Hospitals NHS Trust, University Hospitals Bristol and Weston NHS Foundation Trust, University Hospitals, Leicester, Royal Brompton & Harefield NHS Foundation Trust, King's College Hospital NHS Trust, University Hospital Plymouth NHS Trust
Conditions	Ischemic Heart Disease, Valvular Heart Disease, Cardiovascular Diseases, Surgery-Complications
Enrollment	100 participants
Start Date	2024-05-20
Primary Completion	2025-11 (estimated)
Study Completion	2026-02 (estimated)
Updated on ClinicalTrials.gov	2025-04-03