The extracorporeal circuit consists of a number of dispos- able components that expose the patient to a significant amount of synthetic materials, which include polyvinyl chloride, polycarbonate, polypropylene, stainless steel, polyester and polyurethane. The calculated total surface area of our adult extracorporeal circuit is 4 m2. The diffi- culty in accurately evaluating the surface areas of depth filters and complex components make this a conservative estimate. This synthetic exposure is known to initiate cel- lular and humoral inflammatory reactions1–5 and is highly thrombogenic if the patient is not adequately heparinized.6 Systemic inflammation, reduced platelet count and reduced platelet function have all been correlated to chest tube bleeding during the first 24-hour post-operative period.