Background During extracorporeal membrane oxygenation (ECMO), the risk of thrombosis is important due to the non-biological surfaces of the circuit. Unfractionated heparin (UFH) is required in children during ECMO to maintain circuit patency and prevent thrombosis. The use of heparin induces consumption of antithrombin III (ATIII) and a decrease in ATIII levels may result in decreased efficacy of heparin. Therefore, an monitoring of anticoagulation should be done (anti-factor Xa (anti-Xa), activated clotting time (ACT) and ATIII.) Anti-Xa is monitored until levels are between 0.4 and 0.6 IU/mL. ACT must be increased more than three times. When ATIII activity is lower than 70%, addition of antithrombin concentrate (ATC) is considered. This use of ATC is off-label. In some studies, administration of ATC decreased UFH dose requirements and in other studies no difference was found in the heparin infusion rate.
Purpose The aim of this study was to evaluate the impact of administration of ATC on anti-Xa levels and heparin requirements among children on ECMO.
Material and methods We carried out a retrospective study including all patients requiring ECMO in 2015 and with at least one administration of ATC. ATIII activity levels, UFH dose and anti-Xa levels were collected and compared before and after ATC administration (Student t-test).
Results In 2015, 28 patients received ATC during ECMO in our hospital; 2 patients were excluded because of lack of biological results. Mean ATIII activity pre- and post-administration was 45.8% and 85.4%, respectively. ATIII levels increased significantly after ATC administration (p<0.001). Mean anti-Xa levels pre- and post-administration were 0.36 and 0.53 IU/mL, respectively. Anti-Xa levels were significantly different before and after ATC administration (p<0.001). UFH doses pre- and post-administration were 25.8IU/kg/h and 27.1IU/kg/h, respectively. ATC administration had no influence on UFH dose requirements (p=0.39).
Conclusion ECMO is a common procedure associated with an off-label use of ATC. In this study, ATIII levels and anti-Xa levels increased significantly after ATC administration but UFH doses were not changed after ATC. This study could enable us to review our anticoagulation protocol during ECMO, particularly by decreasing UFH requirements. Future prospective studies are warranted to evaluate the benefits of antithrombin replacement.
No conflict of interest
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