Use of Thromboelastography in Children on Extracorporeal Membrane Oxygenation

Background: Extracorporeal membrane oxygenation (ECMO) profoundly impacts inflammatory and coagulation pathways, and strict monitoring is essential to guide therapeutic anticoagulation to reduce the risk of such complications. Thromboelastography (TEG) may be a valuable measurement of coagulation in these patients, as it offers a global evaluation of the entire clotting cascade as opposed to a single value. There is a paucity of data attempting to reliably correlate TEG parameters with the standard measures of coagulation in heparinized pediatric patients. The aim of our study was to analyze whether TEG parameters correlate with traditional measures of coagulation during ECMO and whether specific TEG parameters can predict bleeding or clotting during ECMO runs.

Methods: We performed a retrospective review of all children under age 18 who were on ECMO at our institution between February 2010 and May 2019. Limited demographics, complication data, hospital disposition, and matched laboratory samples were analyzed. Complications were counted if the patient required intervention (surgical exploration, intracranial hemorrhage, circuit change, limb or organ ischemia). TEGs were performed with heparinase to mitigate anticoagulant effect. Standard measures of coagulation were matched to TEGs drawn within 30 minutes of each other. Laboratory values within 12 hours of a bleeding or clotting complication were also analyzed.

Results: We identified 296 unique patients with 331 ECMO runs within the study period. The majority (55%, n=163) were male and had a median age of 56.5 (1, 363.5) days at the time of cannulation. 48% (n=142) survived to hospital discharge. 158 (47.7%) ECMO runs were identified as having at least one bleeding complication, and 100 (30.2%) were identified as having at least one clotting complication. 74.3% (n=246) of ECMO runs had at least one set of matched laboratory samples and thus provided 2502 matched samples to be included in our analysis. INR was a significant predictor of R-time, the measure indicating the time to clot initiation (β=29.12, p<0.001). Platelets were a significant predictor of α-angle, the measure indicating the speed at which the clot formed (β=0.066, p<0.001). Fibrinogen (β=0.045, p<0.001) and platelets (β=0.045, p<0.001) were each significantly associated with maximum amplitude (MA), the measure indicating the overall strength of the clot. When evaluating laboratory values at the time of complications, no TEG parameter was found to be significantly associated with any bleeding complications (p>0.05).

Conclusion: TEG is a reliable measure of whole-blood coagulation in heparinized pediatric ECMO patients and has significant associations with traditional measures of coagulation.