ACTIVATION OF THE CLOTTING SYSTEM DURING EXTRACORPOREAL MEMBRANE-OXYGENATION IN TERM NEWBORN-INFANTS

Objective: To determine the degree of clotting activation that occurs with the usual anticoagulation regimen with systemic heparinization. M ethods: To allow a standardized comparison of the patients, this study focused on the first 48 hours of extracorporeal membrane oxygenation (ECMO) in term newborn infants, The ECMO perfusion circuit consisted o f a roller pump, silicone membrane lungs, and silicone rubber tubing, Coagulation was controlled routinely by measuring prothrombin time, fi brinogen, antithrombin III, and reptilase time. Platelet counts, activ ated clotting time, and heparin concentration were controlled regularl y, The following specific activation markers of the clotting system we re measured: prothrombin activation fragment 1 + 2 (F-1+2), thrombin-a ntithrombin III complexes, and D-dimer, Measurements were done before the start of ECMO, after 5 minutes, and at hours 1, 2, 3, 4, 6, 12, 24 and 48. Results: All seven term infants had excessively high levels o f clotting activation markers within the first 2 hours of ECMO: F-1+2, 11.6 (+/- 0.9) nmol/L (mean +/- SEM); thrombin-antithrombin, 920 (+/- 2.2) mu g/L; D-dimer, 15.522 (+/- 3.689) ng/L, During the next 46 hou rs of ECMO, F-1+2 and thrombin-antithrombin III complexes decreased fr om those high values, whereas D-dimer did not, The increase of activat ion markers was accompanied by low fibrinogen, low platelet counts. an d prolongation of reptilase time. Conclusions: These findings fit the pattern of consumptive coagulopathy during neonatal ECMO, especially i n the first 24 hours.