Clinical controversies in anticoagulation monitoring and antithrombin supplementation for ECMO

During extracorporeal membrane oxygenation (ECMO), a delicate balance is required to titrate systemic anticoagulation to prevent thrombotic complications within the circuit and prevent bleeding in the patient. Despite focused efforts to achieve this balance, the frequency of both thrombotic and bleeding events remains high. Anticoagulation is complicated to manage in this population due to the complexities of the hemostatic system that are compounded by age-related developmental hemostatic changes, variable effects of the etiology of critical illness on hemostasis, and blood-circuit interaction. Lack of high-quality data to guide anticoagulation management in ECMO patients results in marked practice variability among centers. One aspect of anticoagulation therapy that is particularly challenging is the use of antithrombin (AT) supplementation for heparin resistance. This is especially controversial in the neonatal and pediatric population due to the baseline higher risk of bleeding in this cohort. The indication for AT supplementation is further compounded by the potential inaccuracy of the diagnosis of heparin resistance based on the standard laboratory parameters used to assess heparin effect. With concerns regarding the adverse impact of bleeding and thrombosis, clinicians and institutions are faced with making difficult, real-time decisions aimed at optimizing anticoagulation in this setting. In this clinically focused review, the authors discuss the complexities of anticoagulation monitoring and therapeutic intervention for patients on ECMO and examine the challenges surrounding AT supplementation given both the historical and current perspectives summarized in the literature on these topics

Context-Responsive Anticoagulation Reduces Complications in Pediatric Extracorporeal Membrane Oxygenation

Purpose: We sought to determine the impact of a comprehensive, context-responsive anticoagulation and transfusion guideline on bleeding and thrombotic complication rates and blood product utilization during extracorporeal membrane oxygenation (ECMO).Design: Single-center, observational pre- and post-implementation cohort study.Setting: Academic pediatric hospital.Patients: Patients in the PICU, CICU, and NICU receiving ECMO support.Interventions: Program-wide implementation of a context-responsive anticoagulation and transfusion guideline.Measurements: Pre-implementation subjects consisted of all patients receiving ECMO between January 1 and December 31, 2012, and underwent retrospective chart review. Post-implementation subjects consisted of all ECMO patients between September 1, 2013, and December 31, 2014, and underwent prospective data collection. Data collection included standard demographic and admission data, ECMO technical specifications, non-ECMO therapies, coagulation parameters, and blood product administration. A novel grading scale was used to define hemorrhagic complications (major, intermediate, and minor) and major thromboembolic complications.Main Results: Seventy-six ECMO patients were identified: 31 during the pre-implementation period and 45 in the post-implementation period. The overall observed mortality was 33% with no difference between groups. Compared to pre-implementation, the post-implementation group experienced fewer major hemorrhagic and major thrombotic complications and less severe hemorrhagic complications and received less RBC transfusion volume per kg.Conclusions: Use of a context-responsive anticoagulation and transfusion guideline was associated with a reduction in hemorrhagic and thrombotic complications and reduced RBC transfusion requirements. Further evaluation of guideline content, compliance, performance, and sustainability is needed