Activated Clotting Times Demonstrate Weak Correlation With Heparin Dosing in Adult Extracorporeal Membrane Oxygenation.

BACKGROUND

The optimal monitoring strategy for anticoagulation management in extracorporeal membrane oxygenation (ECMO) remains a clinical controversy. The Extracorporeal Life Support Organization Anticoagulation Guidelines suggest that multiple anticoagulation assays may be needed but do not specify a preferred management strategy.

STUDY QUESTION: In adult ECMO patients, which anticoagulation assays demonstrate the highest correlation with unfractionated heparin (UFH) dose requirements?

STUDY

DESIGN

We performed a retrospective chart review of adult patients cannulated to ECMO between February 2013 and July 2015.

MEASURES AND OUTCOMES: The primary outcome was the correlation between activated clotting time (ACT), activated partial thromboplastin time (aPTT), and anti-Xa and UFH dose. Secondary outcomes included correlations between anticoagulation assays. Correlations were calculated for the entire cohort, with subgroup analysis of venoarterial and venovenous ECMO patients.

RESULTS

Forty-eight patients were included in the analysis, 26 initially cannulated to venoarterial ECMO and 22 to veno-venous ECMO. The median duration of ECMO therapy was 7 days. Mean UFH requirements were 1149 units/h or 15.3 units/kg/h. Total UFH dose was most correlated with anti-Xa levels (r = 0.467), whereas weight-based heparin dose was most correlated with aPTT (0.405). For correlations between anticoagulation assays, anti-Xa and aPTT were more highly correlated with each other (r = 0.633) compared with ACT.

CONCLUSIONS

In adult patients requiring ECMO, anti-Xa and aPTT monitoring were correlated more closely with UFH dosing than ACT.