Evaluation of post-cardiopulmonary bypass Sonoclot signatures in patients taking nonsteroidal anti-inflammatory drugs.
Patients who take nonsteroidal anti-inflammatory drugs (NSAID) and who experience bleeding after cardiopulmonary bypass (CPB) are treated empirically with platelet transfusions because of the unavailability of rapid and accurate diagnostic clotting function tests. Therefore, a Sonoclot Analyzer (Sienco, Inc, Morrison, CO), which measures the change in the viscoelastic properties of recalcified whole blood, was used to assess platelet function in 51 patients undergoing CPB for cardiac surgery. Seventeen patients (group 1) taking NSAID were compared with 34 patients who were not taking NSAID (group 2). Blood samples were drawn for Sonoclot analysis before and after CPB. Chest tube drainage was measured for 24 hours postoperatively in both groups. Clot retraction, measured by the down slope on the Sonoclot signature, decreased significantly in group-1 patients, although values obtained for both groups were in the normal range. No difference was found between groups when Sonoclot signatures were compared, requirements for replacement of clotting factors or platelets, chest tube blood drainage, and unscheduled return to the operating room for bleeding. It is concluded that patients taking NSAID did not experience increased bleeding after cardiopulmonary bypass and that empiric platelet transfusion seemed unnecessary. In addition, the Sonoclot Analyzer seems to be a useful and sensitive instrument for rapidly assessing platelet function in the operating room.