Therapeutic donor hypothermia following brain death to improve the quality of transplanted organs

RATIONALE: Solid organ transplantation is the optimal treatment for patients living with end-stage organ failure. Globally, the majority of organ donors are deceased, most commonly following brainstem death. The process of brain death is known to cause significant injury to organs. Therefore, efforts to optimise the pre-donation care of these donors should be maximised to achieve improved recipient outcomes. OBJECTIVES: To assess the benefits and harms of therapeutic donor hypothermia in recipients of organs donated from brain-dead donors. SEARCH METHODS: We searched Cochrane Kidney and Transplant's Specialised Register, CENTRAL, MEDLINE, Embase and two trials registers up to 03 September 2025. ELIGIBILITY CRITERIA: All randomised controlled trials (RCTs) and quasi-RCTs (RCTs in which allocation to treatment was obtained by alternation, use of alternate medical records, date of birth or other predictable methods) investigating therapeutic donor hypothermia compared with donor normothermia following brainstem death to improve the quality of transplanted organs. OUTCOMES: Critical outcomes were post-transplant outcomes (delayed graft function (DGF), graft survival), utilisation and donor adverse events. Important outcomes were patient survival, primary nonfunction, acute rejection, quality of life and cardiovascular disease. RISK OF BIAS: We used Cochrane's risk of bias 1 tool. SYNTHESIS METHODS: Two review authors independently selected trials for inclusion, assessed methodological quality and risk of bias, and extracted data. We used random-effects models for the meta-analysis. We assessed the certainty of evidence using the GRADE approach. INCLUDED STUDIES: We included four studies, enrolling 2096 donors. Two studies compared donor hypothermia versus normothermia in kidney transplantation. Two studies investigated kidney, heart, lung, liver and pancreas transplantations. SYNTHESIS OF RESULTS: Four studies assessed the impact of donor hypothermia compared with normothermia on kidney outcomes. Donor hypothermia may not reduce the rate of kidney DGF compared to donor normothermia (RR 0.87, 95% CI 0.71 to 1.08; I² = 57%; 4 studies, 3015 participants; low-certainty evidence). Donor hypothermia may not be associated with one-year kidney graft survival (HR 0.77, 95% CI 0.51 to 1.14; I² = 0%; 3 studies, 2075 participants; low-certainty evidence) or one-year patient survival in kidney transplant recipients (HR 0.81, 95% CI 0.42 to 1.57; 1 study, 526 participants; low-certainty evidence). No studies assessed the impact on primary non-function of the kidney or acute rejection. Evidence from only one RCT was available for other solid organ post-transplant outcomes. Donor hypothermia may show no difference to graft survival (lung transplant: HR 0.73, 95% CI 0.21 to 2.51; 1 study; low-certainty evidence; liver transplant: HR 0.85, 95% CI 0.35 to 2.06; 1 study; low-certainty evidence). Donor hypothermia has no impact on liver utilisation (RR 1.02, 95% CI 0.96 to 1.08; I² = 0%; 2 studies, 1259 participants; high-certainty evidence) and probably has no impact on the utilisation of the following organs: kidney (RR 0.99, 95% CI 0.95 to 1.03; I² = 44%; 4 studies, 4265 participants; moderate-certainty evidence); heart (RR 1.03, 95% CI 0.87 to 1.21; I² = 0%; 2 studies, 1259 participants; moderate-certainty evidence); lung (RR 0.97, 95% CI 0.85 to 1.11; I² = 0%; 2 studies, 2518 participants; moderate-certainty evidence); pancreas (RR 1.09, 95% CI 0.74 to 1.61; I² = 0%; 2 studies, 1259 participants; moderate-certainty evidence). Donor hypothermia may not affect the occurrence of donor adverse events (RR 1.28, 95% CI 0.45 to 3.62; I² = 12%; 3 studies, 2015 participants; low-certainty evidence). No data were available for primary nonfunction, acute rejection, quality of life or cardiovascular diseases. Most studies focused on kidney transplant outcomes, with limited data on other organs. The certainty of the evidence was generally low to moderate, primarily due to imprecision, high risk of reporting bias, or both. AUTHORS' CONCLUSIONS: This review provides low-certainty evidence that donor hypothermia may have no impact on post-transplant outcomes. Donor hypothermia may not be associated with reduced organ utilisation. No safety concerns were identified, and donor hypothermia may not increase donor adverse events. FUNDING: No specific funding was received. REGISTRATION: Protocol (2023): doi:10.1002/14651858.CD015190.