Pulmonary injury after total or partial cardiopulmonary bypass with thromboxane synthesis inhibition

Previous studies have shown an increase in left atrial plasma thromboxane (TBX) level and associated increase in lung injury parameters after total cardiopulmonary bypass (t-CPB) but not after partial cardiopulmonary bypass (p-CPB). We used dazmegrel to study the effect of TBX synthesis inhibition on lung injury after t-CPB compared with p-CPB. Sheep were placed on t-CPB without ventilation and with pulmonary artery occlusion (n = 7) or p-CPB with ventilation and an unrestricted pulmonary artery (n = 7). All sheep were treated with dazmegrel. After 90 minutes we separated the sheep from CPB. Plasma TBX, platelets, white blood cells, protein concentration, lung lymph protein, flow, and pulmonary vascular resistance were measured before and after CPB. Lung biopsies were also obtained. Minimal derangement of these pulmonary parameters was seen after either p-CPB or t-CPB. Inhibition of TBX synthesis virtually eliminated the lung injury previously reported after t-CPB, when compared with p-CPB. Clearly TBX has an important role in mediating lung injury after t-CPB.