Biomaterial development for cardiopulmonary bypass

Cardiopulmonary bypass (CPB) is dependent on materials foreign to the patie nt for its successful application. When blood comes into contact with these so-called biomaterials, an inappropriate inflammatory response, which can be life-threatening in some patients, may develop. The reason for this inap propriate activation of host defence mechanisms is not entirely clear, howe ver a number of strategies have evolved over the years to minimize this unw anted sequelae of CPB. These strategies include surface coating of the mate rials of the circuit, using new materials thought to improve biocompatibili ty, and using a number of pharmacological interventions designed to suppres s the inflammatory response. Recently, there has been some evidence which i ndicates that the plasticizer employed in the polyvinyl chloride (PVC) tubi ng of the CPB circuit may play a part in the development of the inflammator y response. The work described in this paper tends to support this thesis. These studies showed that by washing the plasticizer from the surface of th e PVC tubing, the biocompatibility, as reflected in the upregulation of CID 11b on the surface of neutrophils, was enhanced. Furthermore, the use of no n-plasticized substitutes for PVC had a similar effect. The benefit from re moving the plasticizer was similar to that gained from surface coating with heparin, one of the conventional approaches to reducing the inflammatory r esponse to CPB.