THROMBOELASTOMETRIC ASSAY FOR MONITORING HEMOSTASIS DURING EXTRACORPOREAL MEMBRANE OXYGENATION IN ACUTE RESPIRATORY DISTRESS SYNDROME PATIENTS

Acute respiratory distress syndrome (ARDS) is a serious reaction to injuries of the lung. This condition is often fatal, usually requiring mechanical ventilation and admission to an intensive care unit. Extracorporeal membrane oxygenation (ECMO) is widely used as rescue therapy in the course of severe ARDS despite mechanical ventilation. The main problem in ECMO is the activation of haemostasis due to the foreign surface of the extracorporeal circuit. Bleeding and/or thrombosis are frequent complications in ECMO treatment. This study was aimed to investigate the hemostatic system by thrombelastometry and aPTT point-of-care (POC) device, in 15 patients with ARDS undergoing venovenous ECMO: 7 patients with influence A(H1N1), 3 with lung trauma and 5 with bacterial infectious. The ECMO mean duration was 9.2±6.0 days. Thromboelastometry was performed on native blood by ROTEM analyzer (Tem-International, Germany). The onset of coagulation (coagulation time, CT), kinetics of clot formation (CF) and maximum clot firmness (MCF) were measured by NaTEM assay (non-activated TEM). APTT was measured by POC coagulometer (Hemochron-ITC, USA). Anticoagulation with unfractionated heparin was titrated to an aPTT of 50-70 sec. NaTEM assay showed a shortening of CT (39.7%, p<0.001), CFT(21.5%, p<0.01) and an increase of MCF (+27.5%, p<0.001) in the second day in comparison to the first one. Throughout remaining period, CT and CFT prolonged, whereas MCF decreased, obtaining similar values to the first day. A marked shortening of CT, CFT (28% and 8%, respectively, p<0.01) and a significant increase of MCF (+200%, p<0.0001) in comparison to previous values was observed, in the fourth day, in the patient in whom membrane oxygenator was changed due to the presence of clots. These data indicate that thromboelastometry could be a useful tool to monitoring haemostasis in ARDS patients on ECMO and early identify complications.