Objective To compare normothermic (35°C–36°C) versus hypothermic (28°C) cardiopulmonary bypass (CPB) in paediatric patients undergoing open heart surgery to test the hypothesis that normothermic CPB perfusion maintains the functional integrity of major organ systems leading to faster recovery.
Methods Two single-centre, randomised controlled trials (known as Thermic-1 and Thermic-2, respectively) were carried out to compare the effectiveness and acceptability of normothermic versus hypothermic CPB in children with congenital heart disease undergoing open heart surgery. In both studies, the co-primary clinical outcomes were duration of inotropic support, intubation time and postoperative hospital stay.
Results In total, 200 participants were recruited; 59 to the Thermic-1 study and 141 to the Thermic-2 study. 98 patients received normothermic CPB and 102 patients received hypothermic CPB. There were no significant differences between the treatment groups for any of the co-primary outcomes: inotrope duration HR=1.01, 95% CI (0.72 to 1.41); intubation time HR=1.14, 95% CI (0.86 to 1.51); postoperative hospital stay HR=1.06, 95% CI (0.80 to 1.40). Differences favouring normothermia were found in urea nitrogen at 2 days geometric mean ratio (GMR)=0.86 95% CI (0.77 to 0.97); serum creatinine at 3 days GMR=0.89, 95% CI (0.81 to 0.98); urinary albumin at 48 hours GMR=0.32, 95% CI (0.14 to 0.74) and neutrophil gelatinase-associated lipocalin at 4 hours GMR=0.47, 95% CI (0.22 to 1.02), but not at other postoperative time points.
Conclusions Normothermic CPB is as safe and effective as hypothermic CPB and can be routinely adopted as a perfusion strategy in low-risk infants and children undergoing open heart surgery.
Trial registration number ISRCTN93129502.
- Congenital Heart Disease
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MC and KP contributed equally.
Contributors MC: chief investigator, responsible for study conception; surgical expertise and responsible for delivering the intervention to participants. Overall responsibility for the study. Corresponding author KP: responsible for preparing the statistical analysis plan, with advice from CAR, undertaking analyses and preparing a first draft of the manuscript. SB: managed the trial, including protocol amendments and reports. KSh: responsible for approaching and recruiting patients. KSe: responsible for approaching and recruiting patients. LE: managed the trial, including site initiation. SS: co-investigator with surgical expertise and responsibility for delivering the intervention to participants. AP: co-investigator with surgical expertise and responsibility for delivering the intervention to participants. GC: carrying out analyses and producing tables and graphs. LC: provided trial management expertise and advice. GDA: co-investigator providing surgical expertise. RP: co-investigator with surgical expertise and responsibility for delivering the intervention to participants. CAR: co-investigator with responsibility for delivering the study results and report; critical review of the drafted manuscript.
Funding The British Heart Foundation, Cardiovascular theme of NIHR Bristol Biomedical Research Centre and Garfield Weston Trust, supported this work. This study was designed and delivered in collaboration with the Clinical Trials and Evaluation Unit, a UKCRC registered clinical trials unit which, as part of the Bristol Trials Centre, is in receipt of National Institute for Health Research CTU support funding.
Competing interests None declared.
Patient consent Parental/guardian consent obtained.
Ethics approval Thermic-1: North Somerset and South Bristol, reference E4766; Thermic-2: South West—Central Bristol, reference 11/SW/0122.
Provenance and peer review Not commissioned; externally peer reviewed.
Data sharing statement There is no additional data; everything is included in the supplement.
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