ABSTRACT
BACKGROUND: Performance of a majority of cardiac surgical procedures requires the use of extracorporeal circulation. Contact of the patients' blood with the nonendothelial surface of the cardiopulmonary bypass circuit is responsible for several, potentially harmful systemic reactions. METHODS: The patients' response to extracorporeal circulation is reviewed briefly. The interactions between patient and circuit are discussed not only as they relate to blood-material contact, but also from a mechanical and rheologic standpoint. The theoretic benefits of the newer, more hemocompatible materials are presented, along with a review of published clinical experience with heparinized cardiopulmonary bypass circuits. RESULTS: The response to extracorporeal circulation extends far beyond a simple derangement of hemostasis. This inflammatory response is strongly influenced by the rheologic design of the circuit and by the physical and chemical properties of the surface. Heparinized 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 circuit design. Newer, heparinized materials offer real but limited clinical benefits.
Subject(s)
Biocompatible Materials , Blood , Cardiac Surgical Procedures , Extracorporeal Circulation/instrumentation , Cardiopulmonary Bypass/adverse effects , Cardiopulmonary Bypass/instrumentation , Extracorporeal Circulation/adverse effects , Heparin , Humans , Inflammation/etiologyABSTRACT
New agents such as recombinant human erythropoietin (rHu EPO) modify conventional transfusionnal strategies. For accurate indications, such as, anaemia associated with chronic renal failure, cancer or cardiac disease, the preoperative prescription of rHu EPO may reduce transfusion requirements. rHu EPO may also be associated with pre-deposit transfusion in patients with anaemia before blood donation, when the transfusion needs are high, or the period for blood pre-deposit donation shortened. Postoperatively rHu EPO is only efficient if it is administered for a prolonged period; this condition limits its indications and value because of its high cost.
