Monitoring of the Blood Response in Blood Purification

Abstract

A principal objective of monitoring the blood response in procedures such as hemodialysis and cardiopulmonary bypass is to achieve an enhanced understanding of the relationship between blood component alterations and the biomaterials employed. The aim in a study of blood-biomaterial interactions of deriving a correlation between a characteristic of the biomaterial and a representative parameter of the blood response can be influenced in a clinical situation by antithrombotic agents, multimaterial contact, device utilization, blood condition, drug therapy, and the nature of the application. The selection of parame-ters representative of the blood response may require a compromise between the advantages of multiparameter assessment and the benefit of measuring a single parameter by a consistent methodology. Representative parameters are protein adsorption, platelet reactions, intrinsic coagulation and the contact activation phase, fibrinolysis, leukocyte alterations, and complement activation. Assessment during clinical application can be approached by consideration of blood response patterns.

Hemocompatibility during extracorporeal circulation for cardiopulmonary bypass

“…The deleterious effects associated with open-heart surgery have been attributed to various aspects of hemo-incompatibility of CPB. In this respect, the contact of blood with the extracorporeal circuit during CPB has been implicated as the primary source of blood activation that inevitably leads to activation of blood related processes [4][5][6][7][8][9][10][11][12], which can be harmful for the patient by jeopardizing his morbidity during recovery of his surgical treatment. When blood circulates within the vascular system, it is in contact with a continuous luminal endothelial cell layer that is capable of producing, secreting, and binding both anticoagulants and procoagulants to maintain blood fluidity and vascular integrity.…”

“…In addition, long-term contact with the surface of devices like ventricular assist devices and other extracorporeal life support systems could induce an additional set of problems (e.g. disseminated intravascular coagulation) related to impaired hemostasis and systemic inflammatory response [6,25,[28][29][30][31][32][33]. The amount of the systemic anticoagulant should therefore be as low as possible, but still high enough to prevent significant thrombogenesis.…”

“…Devices implanted in the cardiovascular system provoke a variety of host responses, some of them clinically significant. Short-term (a few hours) contact of extracorporeal devices with blood during cardiopulmonary bypass for open-heart surgery inevitably causes activation of the complement cascade and the blood coagulation pathway [4][5][6][7][8][9][10][11][12]. The use of anticoagulant drugs, however, counterbalances the inherently thrombogenic nature of the devices' blood contacting surfaces.…”

“…Moreover, antithrombotic therapy is not always adequate or possible [24][25][26][27]. In addition, long-term contact of devices like ventricular assist devices and extracorporeal life support systems could induce an additional set of problems related to impaired hemostasis and whole body inflammatory response [6,25,[28][29][30][31][32][33]. The amount of the systemic anticoagulant should therefore be as low as possible, but significant thrombogenesis must be prevented.…”