Are in-vitro platelet function tests useful in predicting blood loss following open heart surgery?
BACKGROUND
We investigated the suitability of two commercially available in-vitro bleeding tests (IVBT), the PFA-100 and the Hepcon HMS, to predict blood loss following operations with extracorporeal circulation (ECC) and compared them with conventional coagulation studies.


METHODS
In 40 patients subjected to elective open heart surgery with ECC a blood sample was taken before and after ECC to measure platelet count, prothrombin time, aPTT, D-dimers, fibrinogen, and PFA-100 and Hepcon HMS data. The postoperative blood loss was recorded hourly until removal of drains.


RESULTS
A significant correlation was found between total blood loss (250-1750 ml) and the preoperative PFA-100 (r = 0.41, p = 0.022), the preoperative platelet count (r = -0.42, p = 0.007), the preoperative D-dimer concentration in the plasma (r = 0.41, p = 0.01), and duration of ECC (r = 0.35, p = 0.044). There was no significant correlation between blood loss and the Hepcon HMS system.


CONCLUSIONS
Although a significant correlation was found between blood loss and the PFA-100 IVBT, the practical value of these tests in the clinical situation is limited due to a great variability in individual results.
Department of Thoracic and Cardiovascular Surgery, University of Regensburg, Germany.
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Wahba
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Sander
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Birnbaum
D000368:Aged; D016063:Blood Loss, Surgical; D006348:Cardiac Surgical Procedures; D017558:Elective Surgical Procedures; D005112:Extracorporeal Circulation; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010865:Pilot Projects; D010979:Platelet Function Tests; D011237:Predictive Value of Tests