Therapeutic platelet transfusions are widely accepted as indicated in patients with severe thrombocytopenia and/or platelet dysfunction associated with active serious bleeding (WHO grade of ≥ 2) [10
]. Prophylactic platelet transfusions are widely employed based upon the patient’s underlying illness and the perceived clinical assessment of bleeding risk. However, due to decreased supply and increased concerns about the risks of platelet transfusion, the concept of prophylactic platelet transfusion is being challenged as perhaps being without evidence base, and potentially doing more harm than good for some patients.
Identifying an appropriate platelet count trigger for platelet transfusion has been one of the major challenges in weighing the risk to benefit ratio of prophylactic transfusions. A platelet count of ≤5000/μL is associated with substantial increases in spontaneous hemorrhage in chronically thrombocytopenic patients with an intact vascular system [11
]. Four randomized trials failed to demonstrate significant differences in bleeding risks comparing prophylactic platelet transfusion triggers of 10,000 versus 20,000/μL [12
]. Consequently, a platelet count of 10,000/μL is now widely recommended as a trigger for prophylactic platelet transfusion in patients with thrombocytopenia due to bone marrow disorders, chemotherapy, or hematopoietic progenitor cell transplantation [16
Platelet transfusion dose effects on posttransfusion platelet counts and interval-to-next transfusion have been evaluated in three prospective studies [18
]. All results were interpreted as favoring higher doses of platelet transfusions. Although platelet transfusion rate decreased with larger doses, there were no differences in hemorrhagic events. A platelet dose of 0.07 × 1011
/kg was recommended for stable thrombocytopenic patients and 0.15 × 1011
/kg for patients with acute platelet consumption [14
]. However, a recent large trial found no difference in bleeding episodes and minimal increase in transfusion dosing employing half the traditional dose of platelets (Platelet Dose Trail, “PLADO Trial”) [21
Flisberg et al.
assessed the efficacy of the transfused platelets utilizing rotational thromboelastometry immediately after a single transfusion [22
]. Compared to the pretransfusion data, the clot formation time decreased by 32% (P
= 0.005) and the maximum clot strength increased by 47% (P
= 0.005) with a mean increase in platelet count of 12 × 109
/L. This provides good evidence that transfused platelets are functional immediately after transfusion.