Monitoring anticoagulation during extracorporeal membrane oxygenation in patients with acute respiratory failure

Introduction

aPTT is a common tool for anticoagulation monitor ing during extracorporeal membrane oxygenation (ECMO). Thromboelasto graphy (TEG) is another available option in this setting.

Methods

A prospective observational study on 12 consecutive patients during venovenous ECMO. Anticoagulation was provided with unfractioned heparin titrated to an aPTT ratio target of 1.5 to 2. Kaolin-activated TEG (K-TEG) was contemporarily measured but did not guide heparin infusion. Baseline K-TEG reaction time (R) >20 minutes is accepted for anticoagulation but when it exceeds 90 minutes anticoagulation may be too great [1].

Results

Mean ECMO duration was 9 ± 4 days. A total of 152 K-TEGs were collected. Comparison between aPTT and K-TEG R is reported in Table 1. Four patients (33%) had hemorrhagic complications. Neither aPTT nor K-TEG R were significantly different in patients with hemorrhagic events compared with patients without hemorrhagic events but the latter received a significantly lower total heparin dose (P = 0.0097).

Table 1 Comparison between aPTT and K-TEG R

Conclusion

Anticoagulation was excessive in more than one-half of the samples according to TEG monitoring, while negligible based on aPTT.