Anticoagulation Management and Monitoring in ECMO: An International Survey From the ISTH SSC Subcommittee on Pediatric and Neonatal Thrombosis and Hemostasis

Extracorporeal membrane oxygenation (ECMO) remains a life-saving intervention for critically ill patients with cardiac and respiratory failure, yet it introduces significant challenges in anticoagulation management. This international survey conducted by Regling et al. provides a comprehensive overview of current real-world practices in anticoagulation, laboratory monitoring, and hematology involvement across ECMO centers globally. 

The study collected 72 responses from clinicians across 17 countries and five continents, with the majority of respondents affiliated with Extracorporeal Life Support Organization (ELSO) institutions. Both adult and pediatric providers were represented, offering a broad perspective on ECMO practices across age groups. A key finding is that while 92% of centers utilize anticoagulation protocols and 83% employ transfusion protocols, there remains substantial variability in how these protocols are implemented.

Unfractionated heparin (UFH) continues to dominate as the primary anticoagulant, used routinely in over 90% of centers. However, the increasing adoption of bivalirudin—reported in approximately 53% of institutions—signals a shift in practice trends. Bivalirudin offers several theoretical advantages, including predictable pharmacokinetics, independence from antithrombin, and reduced risk of heparin-induced thrombocytopenia (HIT). Despite these benefits, the study highlights that there is still insufficient consensus regarding when to use bivalirudin as a first-line agent versus as a secondary option.

The survey also revealed notable variability in anticoagulant dosing strategies. For UFH, adult centers tend to use lower starting doses (5–20 units/kg/hr), whereas pediatric centers demonstrate a wider dosing range and greater reliance on individualized protocols. Similarly, bivalirudin dosing varied significantly, although most centers reported starting doses between 0.15 and 0.25 mg/kg/hr.

Laboratory monitoring practices remain inconsistent across institutions. The activated partial thromboplastin time (aPTT) is the most commonly used test for both UFH and bivalirudin monitoring, followed by anti-factor Xa assays. Interestingly, the use of activated clotting time (ACT) has declined compared to prior surveys, likely due to its limitations in accuracy. Advanced viscoelastic testing methods such as thromboelastography (TEG) and rotational thromboelastometry (ROTEM) are available in some centers but are infrequently used to guide real-time clinical decisions.

Another important aspect of ECMO management is transfusion support. The study demonstrates that while most institutions have transfusion protocols, thresholds for red blood cell and platelet transfusions vary widely. This inconsistency underscores the lack of standardized evidence-based guidelines and highlights an area for future research.

Hematology involvement in ECMO care remains limited. Although approximately half of institutions include hematology as part of the care team, most consultations occur only in complex cases. Routine hematology participation in daily management or rounds is uncommon. This finding suggests an opportunity to enhance multidisciplinary collaboration, which could improve anticoagulation strategies and patient outcomes.

The survey also explored antithrombin monitoring and replacement practices. While two-thirds of institutions routinely measure antithrombin levels, only a minority consistently replace it. This variability reflects ongoing uncertainty regarding the clinical benefits and risks, particularly concerning bleeding complications.

Importantly, the study identifies that ECMO may sometimes be conducted without anticoagulation in high-risk bleeding scenarios, such as trauma or postoperative states. This highlights the delicate balance clinicians must maintain between preventing thrombosis and minimizing bleeding risk.

Despite its valuable insights, the study has limitations, including a relatively low response rate and potential selection bias, as many respondents were affiliated with specialized ECMO centers. Additionally, survey-based data may not always reflect actual clinical practice.

In conclusion, this international survey underscores the complexity and variability of anticoagulation management in ECMO. While UFH remains the standard of care, the growing use of bivalirudin and evolving monitoring strategies indicate a shifting landscape. The findings emphasize the urgent need for prospective, collaborative research to establish standardized protocols, improve patient outcomes, and