Eligible randomised controlled trials compared normothermia (systemic perfusion or core temperature above 34°C) with hypothermia (core 34°C or below), as an intra-operative temperature management strategy, during cardiopulmonary bypass in adult cardiac surgery. Studies of selective cooling or that compared temperature targets were excluded. The primary outcome was hospital mortality. Sixteen secondary outcomes were listed.
Thirty-seven of 44 studies only included patients who underwent coronary bypass surgery, remaining patients underwent valve surgery (two studies) or either coronary bypass surgery or valve surgery (five studies). Median time in surgery was 99 minutes. The targeted temperature difference was variable and ranged between 3 and 17°C. Most trials included in the review excluded patients who underwent emergency cardiac surgery and patients with concurrent significant medical diseases.
Two reviewers assessed study eligibility.