Cardiac surgery for complex congenital malformations with use of extracorporeal circulation (ECC) predisposes the patient to an excessive systemic inflammatory response and a consecutive capillary leak syndrome. In a prospective, randomized study, the influence of two oxygenators especially designed for pediatric use on inflammatory markers and clinical outcome was investigated.

Forty neonates and infants (body surface area <0.36 m²) undergoing cardiac surgery using ECC were randomised into three groups: in the first group (n = 14) the Medtronic Minimax Oxygenator^® was used, and in the second group (n = 12) the Dideco Liliput 1^® Oxygenator was used, both with 750 ml priming volume. In the third group the Dideco Liliput 1^® Oxygenator was filled with a reduced priming volume of 450 ml.

Parameters of interest for evaluation of a systemic inflammatory response after ECC were IL-6, tumor necrosis factor (TNF)-α, neu-trophil elastase, complement C3 and free hemoglobin (Hb). In addition, erythrocyte, leukocyte and thrombocyte counts, hemoglobin and C-reactive protein (CRP) values were determined at different measurement points before, during and after surgery.

In all three groups, peak values for TNF-α were observed during surgery, whereas IL-6, elastase and free Hb peaked in the first 4 hours. Highest values for leucocytes and CRP were obtained between 24 and 72 hours after surgery. Erythrocyte and thrombocyte counts as well as Hb values were lowest at ECC onset, normalizing under substitution in the first 4 hours after surgery. Using the Liliput/750, higher IL-6 values 1 hour and 4 hours after surgery, and higher TNF-α values during and 1 hour after surgery could be observed, as compared with Minimax and Liliput/450. In spite of our randomization protocol, patients in the Liliput/750 group were significantly smaller and younger than those in the Minimax group. Accordingly, the number of children with a clinically complicated course (capillary leak, and longer duration of catecholamine therapy and ventilation) was higher in the Liliput/750 group.

Using an adequate priming volume, the systemic inflammatory response is similar after employment of the Dideco Liliput 1^® Oxygenator and the Medtronic Minimax^® Oxygenator. Tip-to-tip surface coating of the ECC with either heparin or phosphorylcholine appears to have similar biological effects in neonates and infants undergoing cardiac surgery.