New thoughts on the correct dosing of prophylactic platelet transfusions to prevent bleeding

Recent studies have evaluated the effects of platelet dose on hemostasis.

As long as a critical level of 5000  platelets/μl is maintained, platelet counts do not affect bleeding. The risk of WHO grade 2 or greater bleeding was 25% on days with morning platelet counts of less than 5000/μl and was 17% at platelet counts between 6000 and 80 000/μl (P < 0.001). Therefore, it is not surprising that platelet doses of half to twice the usual dose of 2.2 × 10(11)  platelets/transfusion/body surface area (BSA) do not affect any bleeding grade. However, the risk of grade 2 or greater bleeding is higher in patients receiving an allogeneic hematopoietic stem cell transplant (HSCT, 79%) versus those receiving chemotherapy for hematologic malignancies (73%) or those receiving an autologous HSCT (57%) (P < 0.001 for the latter versus the first two groups). In contrast, in children under 18, the risk of bleeding was higher in all treatment groups than in adults, particularly for children receiving autologous HSCT (93 to 83% based on increasing patient age). However, for none of these treatment categories did platelet dose affect bleeding risk.

Platelet doses in ranges between half to twice the usual dose of 2.2 × 10(11)  platelets/transfusion/BSA have no affect on WHO bleeding grades.