Anticoagulation Monitoring During Pediatric Extracorporeal Membrane Oxygenation

Abstract

In this issue of the journal, Bembea et al. 1 continue the ECMO community's collective search for the holy grail of anticoagulation monitoring for patients on extracorporeal membrane oxygenation (ECMO) in hopes of minimizing the arguably excessive complications of bleeding and thrombosis experienced internationally. 2 Despite many limitations of their prospective observational study, including small numbers and dramatic heterogeneity of their patient populations, one cannot argue with their demonstration of the lack of correlation between our bedside activated clotting time (ACT) testing and more specific measures of anticoagulation, such as anti-Factor Xa. However, what do we make of it all? Does the lack of correlation directly contribute to their relatively high rates of both thrombotic and hemorrhagic complications?Extracorporeal membrane oxygenation clinicians have long recognized the limitations of the global test for anticoagulation upon which we have long relied: the activated clotting time. Quick, relatively cheap and readily available, and reasonably reliable in most patients, it has become our mainstay of management. But we also recognize that when it is off, it can be way off, effected by a variety of factors, including sepsis, D-dimers, hypothermia, and, perhaps most commonly on ECMO, thrombocytopenia. Thus, we seek more specific determinants of preventing circuit thrombosis and patient hemorrhage. Unfortunately, in our desire to find a better monitor, we may be creating a system of "overmeasure and overtreat," with increasing use Department of Pediatric Surgery, Division of Cardiovascular Surgery antithrombin III, and platelets in all patients, in our attempt to reduce the complications in the minority. For example, in this study, the use of AT was discretionary and the use of FFP common. However, in the absence of sepsis and true disseminated intravascular coagulopathy (DIC), I personally have found little use for routine FFP, and rarely give AT III, despite using Amicar fairly liberally, yet I have experienced less

Age-Based Difference in Activation Markers of Coagulation and Fibrinolysis in Extracorporeal Membrane Oxygenation

“…In a subgroup analysis of infectious versus noninfectious etiologies in our study, all the patients with proven infections were over 30 …”

“…There have been some studies addressing the question of whether patients with blood group O have an increased bleeding tendency (28) (as plasma von Willebrand factor [vWF] levels are 25-35% lower in subjects with blood group O than those in non-O individuals) and patients with non-O blood group having increased tendency for thromboembolism (29). Obviously, we must be mindful of just treating laboratory values and everything has to be correlated clinically (30). In our study, since PAP levels stayed elevated in patients older than 30 days who had bleeding complications while on ECMO, we hypothesize that fibrinolysis activation also increases propensity for bleeding in this patient subgroup.…”