Complement activation by in vivo neonatal and in vitro extracorporeal membrane oxygenation.

Complment activation during extracorporeal membrane oxygenation (ECMO) in newborns can be caused by both the underlying disease processes and by blood contact with the ECMO circuit. We investigated the relative importance of these mechanisms by measuring C3a, C5a and sC5b-9 before, during and after neonatal ECMO in six consecutive newborn patients using enzyme-linked immunoassay. In addition complement activation during in vitro ECMO with repeated flow of the same blood volume was measured using blood from healthy adult donors. C3a increased significantly in vivo after 1 h (from 1035+/-193 to 1865+/-419 microg/l) and in vitro ECMO (from 314+/-75 to 1962+/-1062 microg/l). C5a increased during ECMO without significant differences between in vivo and in vitro activation. In neonatal patients, sC5b-9 rose faster than in vitro, but the rapid increase was also significant for in vitro experiments (in vivo: from 328+/-63 to 1623+/-387 microg/l after 2 h; and in vitro: from 78+/-32 to 453+/-179 microg/l after 8 h). After this initial peak at 1-2 h, complement activation decreased gradually until 2-3 days after the initiation of ECMO. We conclude that in newborns the rapid activation of the complement system after the start of ECMO is predominantly caused by contact with artificial surfaces rather than the patient's underlying disease.

Early treatment with erythropoietin beta ameliorates anemia and reduces transfusion requirements in infants with birth weights below 1000 g.

OBJECTIVE: To investigate whether recombinant erythropoietin (rhEPO) reduces the need for transfusion in extremely low birth weight (ELBW) infants (birth weight 500-999 g) and to determine the optimal time for treatment. METHODS: In a blinded multicenter trial, 219 ELBW infants were randomized on day 3 to one of 3 groups: early rhEPO group (rhEPO from the first week for 9 weeks, n = 74), late rhEPO group (rhEPO from the fourth week for 6 weeks, n = 74), or control group (no rhEPO, n = 71). All infants received enteral iron (3-9 mg/kg/day) from the first week. The rhEPO beta dose was 750 IU/kg/week. Success was defined as no transfusion and hematocrit levels never below 30%. RESULTS: Success rate was 13% in the early rhEPO group, 11% in the late rhEPO group, and 4% in the control group (P =.026 for early rhEPO versus control group). Median transfusion volume was 0.4 versus 0.5 versus 0.7 mL/kg/day (P =.02) and median donor exposure was 1.0 versus 1.0 versus 2.0 (P =.05) in the early rhEPO group, the late rhEPO group, and the control group, respectively. Infection risk was not increased and weight gain was not delayed with rhEPO beta. CONCLUSION: Early rhEPO beta treatment effectively reduces the need for transfusion in ELBW infants.