A multi-centre randomised controlled trial of Transfusion Indication Threshold Reduction on transfusion rates, morbidity and healthcare resource use following cardiac surgery: study protocol.

Thresholds for red blood cell transfusion following cardiac surgery vary by hospital and surgeon. The TITRe2 multi-centre randomised controlled trial aims to randomise 2000 patients from 17 United Kingdom centres, and tests the hypothesis that a restrictive transfusion threshold will reduce postoperative morbidity and health service costs compared to a liberal threshold. Patients consent to take part in the study pre-operatively but are only randomised if their haemoglobin falls below 9 g/dL during their post-operative hospital stay. The primary outcome is a binary composite outcome of any serious infectious or ischaemic event in the first three months after randomisation. Many challenges have been encountered in the set-up and running of the study.