Hematology
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The maturation and postnatal development of the human coagulation system was first studied and described more than 20 years ago. These older studies, supported by more recent data, confirm the significant and important differences in the physiology of coagulation and fibrinolysis in neonates and young children compared with older children and adults. Subsequently, significant differences were also described in the physiology of primary hemostasis and in global in vitro tests for hemostasis. ⋯ The concept of "neonatal coagulopathy" has an important impact on both the diagnosis and management of hemorrhagic or thrombotic events in neonates. For diagnosis of hemostasis disorders, diagnostic laboratories processing pediatric samples should use age-, analyzer-, and reagent-appropriate reference ranges. Age-specific guidelines should be followed for the management of neonates with hemostatic disorders.
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Venous thromboembolism (VTE) is an important cause of preventable morbidity and mortality in medically ill patients. Randomized controlled trials indicate that pharmacologic prophylaxis reduces deep venous thrombosis (relative risk [RR] = 0.46; 95% confidence interval [CI], 0.36-0.59) and pulmonary embolism (RR = 0.49; 95% CI, 0.33-0.72) with a nonsignificant trend toward more bleeding (RR = 1.36; 95% CI, 0.80-2.33]. Low-molecular-weight heparin (LMWH) and unfractionated heparin are equally efficacious in preventing deep venous thrombosis (RR = 0.85; 95% CI, 0.69-1.06) and pulmonary embolism (RR = 1.05; 95% CI, 0.47-2.38), but LMWH is associated with significantly less major bleeding (RR = 0.45; 95% CI, 0.23-0.85). ⋯ Graduated compression stockings should be used with caution. VTE prevention in medically ill patients using extended-duration VTE prophylaxis and new oral anticoagulants warrant further investigation. VTE prophylaxis prescription and administration rates are suboptimal and warrant multidisciplinary performance improvement strategies.
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Prophylactic platelet transfusions are the standard of care for patients with hypoproliferative thrombocytopenia after receiving chemotherapy or radiation for the treatment of malignancy, for BM replacement by leukemia or solid tumor, or in preparation for a hematopoietic stem cell transplantation.(1) During this time of thrombocytopenia, these patients may receive both prophylactic platelet transfusions, which are given to prevent potentially life-threatening bleeding when a patient's platelet count drops below a predetermined threshold, and therapeutic platelet transfusions, which are given to treat active or recurrent bleeding. In the 1950s, the invention of the plastic blood bag allowed for the production and storage of platelet concentrates,(2) and in the 1960s, it was recognized that prophylactic platelet transfusions effectively reduced hemorrhagic death in patients with newly diagnosed leukemia.(3,4) In 1962, Gaydos published the paper that is frequently credited with the inception of the 20 000/μL platelet transfusion threshold.(5) Despite a half-century of experience with prophylactic platelet transfusions, there are still insufficient data to provide clinicians with evidence-based guidelines specific to pediatric oncology and hematopoietic stem cell transplantation (HSCT) patients.
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High-level production of β-globin, γ-globin, or therapeutic mutant globins in the RBC lineage by hematopoietic stem cell gene therapy ameliorates or cures the hemoglobinopathies sickle cell disease and beta thalassemia, which are major causes of morbidity and mortality worldwide. Considerable efforts have been made in the last 2 decades in devising suitable gene-transfer vectors and protocols to achieve this goal. ⋯ Partial clonal dominance for an intragenic site (HMGA2) of chromosomal integration of the vector was observed in this patient without a loss of hematopoietic homeostasis. Other patients are now receiving transplantations while researchers are carefully weighing the benefit/risk ratio and continuing the development of further modified vectors and protocols to improve outcomes further with respect to safety and efficacy.