Impact of xenon anaesthesia in isolated cardiopulmonary bypass on very early leucocyte and platelet activation and clearance: a randomized, controlled study.

BACKGROUND Cardiopulmonary bypass (CPB) is associated with leucocyte and platelet activation and also organ dysfunction. Xenon has been found to have organ-protective effects. We therefore investigated the effect of isolated CPB on leucocyte and platelet activation and the efficacy of xenon in inhibiting these changes. METHODS Isolated CPB was conducted according to strict standardized clinical criteria using blood from healthy volunteers. They were randomized to an air-oxygen mixture (control group) vs xenon-oxygen mixture (xenon group). Blood samples were drawn at 5, 15, 30, 60, and 90 min from commencement of circuits and analysed for haemoglobin concentrations, white cell, neutrophil, monocyte, lymphocyte, and platelet counts. Leucocyte and platelet activation and also complex formation were determined by measuring levels of CD14++ monocytes, CD16+ monocytes, platelet-monocyte complexes, and platelet-neutrophil complexes (PNC). Differences between and within the groups were analysed with Student's t-test. RESULTS Biomarker levels were not different between the groups. The data were pooled to identify the effects of isolated bypass. The neutrophils, monocytes, platelets, CD14++ monocytes, and CD16+ monocytes decreased within 5 min of the bypass experiments, whereas the percentage of platelet-CD++ monocyte complexes and PNC increased. CONCLUSIONS Isolated CPB elicited rapid, substantial leucocyte and platelet activation, and xenon had no impact on inhibiting these changes.