Fresh and citrated whole-blood specimens can produce different thromboelastography results in patients on extracorporeal membrane oxygenation.

OBJECTIVES

To compare thromboelastography (TEG) tracings obtained from fresh and citrated whole-blood samples in patients on extracorporeal membrane oxygenation (ECMO) or after cardiopulmonary bypass and in healthy volunteers.

METHODS

Samples of fresh and citrated whole blood were analyzed for 25 patients and 4 healthy volunteers. Thromboelastography analysis was performed in both plain and heparinase cups.

RESULTS

In 5 of 6 patients on ECMO, use of citrated samples resulted in apparent partial or complete heparin reversal. In TEG tracings from patients following cardiopulmonary bypass, there was a slight hypercoagulable appearance in the citrated sample. No differences were noted between fresh and citrated samples from healthy volunteers whose blood was spiked with heparin.

CONCLUSIONS

In some patients on ECMO, use of samples collected in sodium citrate tubes for TEG analysis results in significant artifacts, which could lead to heparin overdosing in these patients.