EXTRACORPOREAL-CIRCULATION, HEMOCOMPATIBILITY, AND BIOMATERIALS

Background. performance of a majority of cardiac surgical procedures r equires the use of extracorporeal. circulation. Contact of the patient s' blood with the nonendothelial surface of the cardiopulmonary bypass circuit is responsible for several, potentially harmful systemic reac tions. Methods. The patients' response to extracorporeal circulation i s reviewed briefly. The interactions between patient and circuit are d iscussed not only as they relate to blood-material contact, but also f rom a mechanical and theologic standpoint The theoretic benefits of th e newer, more hemocompatible materials are presented, along with a rev iew of published clinical experience with heparinized cardiopulmonary bypass circuits. Results. The response to extracorporeal circulation e xtends far beyond a simple derangement of hemostasis. This inflammator y response is strongly influenced by the theologic design of the circu it and by the physical and chemical properties of the surface. Heparin ized circuits decrease inflammation, but the clinical benefits of this reduction remain unclear, except for extended cardiopulmonary support . The safe use of these circuits requires full heparinization and does not reduce allogeneic transfusions. Conclusions. Clinicians are still in the search of the ideal material and the ideal extracorporeal circ uit design. Newer, heparinized materials offer real but limited clinic al benefits.