The Science Journal of the American Association for Respiratory Care

2012 OPEN FORUM Abstracts

LACK OF CORRELATION BETWEEN ACT VALUES AND HEPARIN LEVELS DURING ECMO.

Lee Williford, Desiree Bonadonna, Luther Chambers, Christoph Hornik, Richard Walczak, Ira Cheifetz; Duke University Hospital, Durham, NC

Background: Bleeding and clotting complications during extracorporeal membrane oxygenation (ECMO) can have catastrophic consequences. Activated clotting time (ACT) is traditionally the primary parameter monitored as part of routine ECMO anticoagulation management. Recently, aPTT, antithrombin III levels, and heparin levels are being increasingly monitored. We hypothesize that heparin levels correlate more closely with aPTT than ACT values. Method: As part of a Performance Improvement initiative, data were collected prospectively. ACT, heparin levels, aPTT, and antithrombin III were measured and heparin dose (units per kg) recorded for neonatal and pediatric ECMO patients between January and May 2012. Result: Data were collected for 17 consecutive ECMO patients (median weight 3.7 kg, (5th, 95th %ile = 2.9, 65)). Median heparin dose was 34.3 units/kg/hr (14.2, 69.2). Median duration of ECMO was 205 hours (22.5, 1028). Median ACT was 163 sec (135, 194), and median aPTT was 79.6 (37.8, 150). A weak correlation was noted between heparin level and aPTT with a Spearman’s correlation coefficient of 0.64. No correlation was noted between heparin level and ACT (Spearman’s correlation coefficient 0.27). The Spearman’s correlation coefficient between ACT and aPTT was 0.54. Conclusion: Despite the routine use of heparin infusions for ECMO management, the optimal monitoring of anticoagulation remains uncertain. Our results prompt speculation that a more comprehensive assessment of heparin dosing beyond ACT monitoring, to include heparin levels and aPTT measurements, is needed. Heparin dosing using these methods may result in longer circuit life, decreased blood product exposure, and improved outcomes. Sponsored Research - None