Clinical consequences of alterations in platelet transfusion dose: a prospective, randomized, double-blind trial

BACKGROUND: The dose-response relationship for platelet transfusion has bec ome increasingly important as the use of platelet transfusion has grown. STUDY DESIGN AND METHODS: One hundred fifty-eight prophylactic apheresis pl atelet transfusions were administered to 46 patients undergoing high-dose t herapy followed by hematopoietic progenitor cell transplantation in a prosp ective, randomized, double-blind, multiple-crossover study. Transfusions we re administered in pairs, differing only in platelet content. Each pair con sisted of a lower-dose-platelet component (LDP) and a higher-dose platelet component (HDP) administered in random order to the same patient. LDPs cont ained a mean of 3.1 x 10(11) platelets (range, 2.3-3.5 x 10(11)),and HDPs c ontained a mean of 5.0 x 10(11) platelets (range, 4.5-6.1 x 10(11)). Patien ts with active bleeding and those who were refractory to platelet transfusi ons were excluded. RESULTS: The mean posttransfusion platelet count increment with LDP was 17, 010 per mu L, and that with HDP was 31,057 per mu L (p<0.0001). Only 37 per cent of LDPs resulted in platelet count increments of at least 20,000 per m u L, whereas 81 percent of HDPs resulted in increments above this level (p< 0.0001). The mean transfusion-free interval with LDP was 2.16 days, whereas that with HDP was 3.03 days (p<0.01). Administration of LDPs was associate d with a 39 to 82 percent increase in the relative risk (per day) of requir ing subsequent platelet transfusions (p<0.0001). CONCLUSION: As compared to the administration of HDPs, the administration o f LDPs for prophylactic transfusion in hematopoietic progenitor cell transp lant patients results in a lower platelet count increment, a lower likeliho od of obtaining a posttransfusion platelet increment >20,000 per mu L, a sh orter transfusion-free interval, and a greater relative risk per day of req uiring additional transfusions.