Figure 1

Sample collection during CPB. Upper picture shows all time points at which blood samples were collected. The first was before CPB (‘Pre-op’). Once on CPB, patients were cooled to deep hypothermia and DHCA or ACP was initiated (‘Start’). At the end of DHCA or ACP (‘End’), full-flow CPB was recommenced and the patient was rewarmed to normothermia, during which the ‘30 min’ sample was drawn. Four and 24 hours after surgery, the final samples were collected (‘4 h post-operative’ and ‘24 h post-operative’). The lower picture depicts the arterial and venous samples drawn at the ‘End’ time point. Samples were simultaneously drawn from the arterial and venous cannulae, transporting blood to and from the brain, respectively. ACP, antegrade cerebral perfusion; CPB, cardiopulmonary bypass; DHCA, deep hypothermic circulatory arrest.