Monitoring Anticoagulation in Patients on Extracorporeal Membrane Oxygenation: Current Status and Future Trends

Extracorporeal membrane oxygenation (ECMO) as a modality of life support is being increasingly utilized as a bridge to recovery in patients requiring respiratory and/or cardiac support.Being highly invasive and associated with extracorporeal circulation of blood, a number of complications can arise during ECMO.The most notable among these complications are the ones related to thrombosis and bleeding.Use of a variety of anticoagulants makes it imperative to closely monitor the effect of these medications on the hemostatic milieu of the patient.Guided by the active monitoring of coagulation parameters, continuous active titration of anticoagulation is a necessity to prevent aforementioned complications.Apart from the effect of anticoagulation, patients on ECMO are intrinsically extremely ill with derangements in their physiological parameters, and existence of coagulopathy.To prevent thrombosis in the extracorporeal circuit, it is mandatory to provide some form of anticoagulation.A plethora of drugs with different modes of action are available to achieve this aim.The commonest and the oldest still being heparin, newer anticoagulants include direct thrombin inhibitors, factor Xa inhibitors, direct oral anticoagulants, Xabans, factor-XIIa inhibitors, etc.There is a wide variety of tests of coagulation which include the standard laboratory-based assays like activated partial thromboplastin time (aPTT), anti-factor Xa assay, prothrombin time/international normalized ratio, etc., to point-of-care tests like activated clotting time (ACT), and viscoelastic tests (ROTEM/TEG) are available.Newer real-time continuous monitoring tests for early detection of thrombosis are being developed actively with the aim of providing accurate bedside information which can aid in titration of anticoagulation.