Fecal blood loss: A quantitative method of evaluating hemostasis in patients with thrombocytopenia.

BACKGROUND: The purpose of our studies was to determine if fecal blood loss can provide a quantitative measure of bleeding at platelet counts of 20 000/µL or less in patients with hypoproliferative thrombocytopenia and to document the effects of different prophylactic platelet transfusion triggers on fecal blood loss. METHODS AND MATERIALS: Patients had an aliquot of their autologous red blood cells (RBCs) labeled with 51 Cr. Following reinjection of their radiolabeled RBCs, all feces and a daily blood sample were collected to determine fecal blood loss per day. Three different studies were performed in patients with thrombocytopenia: The first was in patients with thrombocytopenia with aplastic anemia who were not receiving platelet transfusions, and the other two trials involved thrombocytopenic patients with cancer who were receiving prophylactic platelet transfusions at platelet transfusion triggers of 5000/µL, 10 000/µL, or 20 000/µL. RESULTS: In patients with thrombocytopenia not receiving platelet transfusions, fecal blood loss does not increase substantially until platelet counts are 5000/µL or less. When platelet transfusions are given prophylactically to patients with cancer with chemotherapy-induced thrombocytopenia at platelet counts of 5000/µL or less, fecal blood loss and red cell transfusion requirements are the same as those for patients transfused prophylactically at higher transfusion triggers of 10 000 platelets/µL or 20 000 platelets/µL. However, the total number of platelet transfusions needed increases significantly, and the duration of the patient's thrombocytopenia tends to be longer at the higher platelet transfusion thresholds. CONCLUSION: A prophylactic platelet transfusion threshold of 5000/µL or greater is sufficient to maintain hemostasis in patients with thrombocytopenia.

ABO blood group antibody levels in infants exposed to mechanical circulatory support.

ABO sensitization is a barrier to ABO-incompatible heart transplantation in infants. We investigate the development of ABO antibodies in infants with and without mechanical circulatory support (MCS) during their waiting period. Although the proportion of patients with antibodies was similar between the groups, the median age at antibody detection was only 9 days (6-198) for MCS vs. 223 days (28-367) for non-MCS patients (P = 0.028), suggesting MCS is associated with earlier ABO antibody detection.

The transfusion trigger and number of units transfused in patients with HIV: associations with disease stage and functional status.

BACKGROUND: The influence of quality of life (QOL), physical functioning, and HIV disease stage on the transfusion trigger and the number of units transfused was investigated. STUDY DESIGN AND METHODS: The Viral Activation Transfusion Study, a randomized, double-blind study at 11 participating sites, enrolled HIV-positive patients with anemia who required RBC transfusion; 428 patients were included in the analysis of the first transfusion. The QOL scores, Perceived Health Index, Karnofsky score, CD4+ cell count, HIV viral load, and site were analyzed for relationships with the Hb level and the number of units transfused. RESULTS: The transfusion trigger was lower in patients with higher levels of Karnofsky score, Perceived Health Index, CD4+ cell count, and a number of QOL scales. Both the Hb trigger and the number of units transfused had a significant site variation. Males were transfused at a significantly lower Hb level than females. In multivariate analysis, the CD4+ cell count remained significant, but the Karnofsky score or the Perceived Health Index did not. The number of RBC units transfused was associated with the Hb level, CD4+ cell counts, and Karnofsky scores in unadjusted analysis but with only Hb in adjusted analysis. CONCLUSIONS: In this group of HIV+ patients, lower CD4+ cell counts prompted transfusion at higher Hb levels. However, after controlling for the Hb level, the number of units transfused was associated with only the Hb level. The HIV stage appears to influence the decision to transfuse at a particular Hb level but not to influence the number of RBC units transfused. The functional status does not appear to influence the decision to transfuse.