Effect of mild hypothermia vs normothermia cardiopulmonary bypass on postoperative bleeding in patients undergoing coronary artery bypass grafting: protocol of a multi-center, randomized, controlled trial

Abstract

Background: Coronary artery bypass grafting (CABG) is often performed with hypothermic cardiopulmonary bypass (CPB) to reduce metabolic demands and protect the myocardium. However, hypothermia can increase bleeding risks and other complications. Methods: This is a prospective, multi-center, randomized controlled trial. From September 2023 to December 2024, a total of 336 eligible patients planning to undergo on-pump CABG will be enrolled. All participants will be randomly divided into mild hypothermia CPB group (target oxygenator arterial outlet blood temperature at 32–33℃) or normothermia CPB group (target oxygenator arterial outlet blood temperature at 35–36℃). The primary endpoint is Universal Definition of Perioperative Bleeding (UDPB) class 2–4. Secondary endpoints are class of UDPB, levels of coagulation and inflammatory factors, in-hospital mortality, perioperative related complications, ICU length of stay, and hospital length of stay. Discussion: This clinical trial aims to compare the effects of different target temperature during CPB on postoperative bleeding and to explore optimal temperature strategy to provide new clinical evidence. Trial registration: Chictr.org.cn: ChiCTR2300075405. The trial was prospectively registered on 4 September 2023.