Experimental studies in hemo-and biocompatibility of artificial surfaces in cardiovascular surgery

Abstract

Already in 1890 Brown-Sequard investigated artificial blood circulation to the organs; however decades of basic research were carried out until, in 1954, Gibbon first successfully applied extracorporeal circulation (ECC) to a human with the aid of a heart-lung machine (HLM). In the early days of the development of ECC technology there were questions regarding the efficiency of the individual parts: most importantly the pumps and oxygenators. The plate or grid oxygenators then in use were replaced by the so-called bubble oxygenator. Since the latter functions on a completely different principle of oxygenation, it was not surprising that most of the investigations were conducted on the efficiency of the oxygenation involved. However, very soon both systems displayed problems regards hemolysis which in the end were met through the introduction of membrane oxygenators. When these oxygenators came into use it was not completely clear that they would bring with them a whole new range of problems, namely those of surface contact between the artificial membrane and the blood. Here, at the latest, it was to be shown that the problem of blood clotting and that of contact with artificial surfaces combined to form one big problem area. In recent years, it was thought that a way out of these difficulties had been found through the method of coating the membrane oxygenators with heparin, thus, solving both the problem caused by high heparin dosages and that of surface contact with the blood.