Stepwise improvement of cardiopulmonary bypass for neonates and infants

Abstract

Cardiopulmonary bypass (CPB) is a technique that makes open heart surgery possible. When CPB is used the heart can be stopped while the blood circulation, oxygen delivery and carbon dioxide removal are guaranteed. In the last decades CPB has become much safer but still causes a systemic inflammation reaction (SIRS). SIRS may cause morbidity and, when severe, even mortality. SIRS reaction is worse in neonates and infants due to the immaturity of organs and the unfavourable ratio of CPB prime volume to patient circulating volume. This thesis focuses on different techniques that have been developed to decrease the deleterious effects of CPB in pediatric cardiac surgery.We compared in a retrospective way 2 groups of 99 patients each, in one group we used MUF and in the other group ultrafiltration was not used. We concluded that modified ultrafiltration decreases blood transfusion requirements and chest drain loss after pediatric cardiac surgery.The ratio between CPB prime solution and circulating blood volume is highest in the neonatal patient. It has been reported that neonates have a poor antioxidative and iron binding capacity. During CPB, prooxidative substances, such as nonprotein-bound iron, are released while the plasma antioxidant capacity decreases, resulting in excess accumulation of Radical Oxygen Species.Contact of blood with the non-biological surfaces of the CPB system has been designated as the main cause of complement activation. Improving the biocompatibility of CPB systems by means of decreasing the contact activation of blood elements and thereby attenuating the inflammatory response is evidently desired, and for this reason several coatings have been developed. Information is lacking about the interaction of medication and the CPB prime or the coating of a CPB system. We did not observe any interaction between dexamethasone and the PHISIO__ coating, b ut have observed that in the group with PHISIO__ coating without dexamethasone the production of IL-8 was significantly increased. In literature many controversies are found on the topic of CPB coatings. It is difficult to compare these studies due to different patient groups, differences in measured parameters and lack of proper control groups.