PB0308 - Anticoagulation monitoring of UFH (unfractioned heparin) in a pediatric patient during long term ECMO (extracorporeal membrane oxygenation)

Background: ECMO support should be offered in patients with refractory acute hypoxemia who demonstrate progressive persistent failure despite optimized conventional therapies.Anticoagulant therapy is required to prevent procoagulant activity and thrombosis in the patient as well as in the extracorporeal circuit. However, systemic bleeding can occur with anticoagulation therapy. During the ECMO, significant complications can occur due to thrombosis and bleeding, which mandates close anticoagulation monitoring. UFH is the anticoagulant of choice. ECMO guidelines have suggested aPTT (activated partial thromboplastin time) and/or anti-factorXa levels as a better guide to monitoring UFH efficacy. In addition, ROTEM® samples with and without the addition of heparinase allows for the underlying assessment of coagulation in the presence of UFH. However, dose adjustment is done with ACT.

Aims: Describe the laboratory assays performed to monitor UFH in a pacient during long term v-v ECMO.

Methods: A four year old boy with a diagnosis of pneumonia (influenza B). Due to a lack of response to conventional ventilation, it was decided to switch to ECMO for ten days with favorable outcome. He received UFH as an anticoagulant. Anticoagulation monitoring was performed with: aPTT, anti-factorXa, ACT (activated clotting time), ROTEM®, complete blood count (Beckman Coulter® DxH 800), and AT (antithrombin). Haemostasis determinations were performed in Stago Compact®.

Results: Attached graphics.

Conclusion(s): The monitoring tests available to guide UFH management demonstrates that no one test is ideal. In pediatrics, the APTT reference interval vary from the adult population according developmental hemostasis. In the boy described, this test was not usefull to monitor UFH therapy. Direct measurement of UFH’s ability to inhibit specific coagulation proteins, while producing definitive values only represent 1 component of UFH’s inhibitory effect on in vivo coagulation. For this reasons, the management of anticoagulation in ECMO is a complex and multitest issue, involving the interaction of different actors of the health team.