Antigen-matched donor blood in the transfusion management of patients with sickle cell disease.

BACKGROUND: Alloimmunization to red cell antigens is a significant risk in chronically transfused patients with sickle cell disease. Antigen matching, by decreasing the likelihood of alloantibody development, may significantly facilitate long-term management while decreasing morbidity. STUDY DESIGN AND METHODS: The transfusion records of 86 patients who underwent chronic transfusion for sickle cell disease at a tertiary-care medical center were reviewed retrospectively to determine the efficacy of an antigen-matching program in the prevention of alloimmunization to clinically significant red cell antigens. Recipients were phenotyped and given units matched for the K, C, E, S, and Fya or Fyb antigens. RESULTS: None (0%) of the 40 patients who received antigen-matched transfusions showed any evidence of alloimmunization, while 16 (34.8%) of the 46 patients who received both antigen-matched and non-antigen-matched transfusions developed clinically significant alloantibodies. The cost was 1.8 to 1.5 times that for a standard transfusion protocol. CONCLUSION: On the basis of this experience, it is recommended that transfusion centers engaged in the management of chronically transfused sickle cell anemia patients consider providing antigen-matched units for such patients. This is recommended not only because it prevents alloimmunization but also because such a program provides additional clinical benefits to the patient that may outweigh the higher costs of the process.

A non-computer-dependent prospective review of blood and blood component utilization.

The effect that a prospective review of blood and blood component utilization had during a 1-year period at an 850-bed tertiary-care teaching hospital is reported. The review process, which has been in operation for 18 years, is based on institutionally developed usage guidelines for blood, fresh-frozen plasma (FFP), platelets (Plts), and cryoprecipitate (Cryo). The guidelines were developed by the hospital's Transfusion Medicine Committee. The review is initiated by the transfusion service technical personnel when an order is received. Back-up support is provided, as needed, by physicians on the service or by those pathology residents taking off-hour call. They consult with the ordering physician when questions arise as to the appropriateness of an order as it relates to the patient's clinical situation. Screening values used in the initial evaluation of each order are: hematocrit, less than or equal to 27 percent (0.27) for blood; prothrombin time, greater than or equal to 16 seconds, and/or activated partial thromboplastin time, greater than or equal to 60 seconds, for FFP; bleeding time, greater than or equal to 16 minutes and/or a platelet count of 20 to 100 x 10(3) per mm3 (20-100 x 10(9)/L), as related to clinical conditions, for Pits; and fibrinogen less than or equal to 120 mg per dL (1.2 g/L) for Cryo. Also taken into consideration is the stated clinical indication, which is provided when the requisition is submitted. As a result of the prospective review, orders for blood and/or components for 114 patients were canceled, and 51 patients received 207 blood components that were more appropriate for the clinical situation.(ABSTRACT TRUNCATED AT 250 WORDS)

Fibrinolysis in critically ill patients.

Impaired fibrinolysis may contribute to development of adult respiratory distress syndrome (ARDS). Pathologic increases in endogenous plasminogen activator inhibitor (PAI-1) may blunt normal fibrinolysis and unmask alternate fibrinolytic mechanisms, such as elastase-induced fibrin degradation. We measured PAI-1 and elastase-induced fibrin(ogen) degradation products in 69 critically ill patients in our medical intensive care unit (MICU) and in nine healthy volunteers. Factor VIII-related antigen protein (VIII:Ag), a reported marker of acute lung injury, and alpha-1-protease inhibitor (alpha-1-PI), an acute phase reactant, were also measured. MICU patients included 24 control patients with no known risk of ARDS, 35 patients with risk factors for ARDS including sepsis, pneumonia, aspiration, and shock, and 12 patients with ARDS including two patients from at-risk groups who developed ARDS. Plasma PAI-1 was determined by chromogenic assay, elastase-induced peptides by a new radioimmunoassay, VIII:Ag by immunoelectrophoresis, and alpha-1-PI by immunodiffusion. When compared to normal volunteers, MICU control patients had elevated PAI-1, VIII:Ag, elastase-induced peptides, and alpha-1-PI. Patients with ARDS had significantly higher PAI-1 and VIII:Ag than did MICU control patients; elastase-induced peptides and alpha-1-PI were not higher. However, at-risk patients who did not develop ARDS also had high PAI-1 or VIII:Ag. Although these data cannot refute the possible role of these compounds in the pathogenesis of ARDS, they demonstrate that PAI-1 and VIII:Ag may be elevated in many critically ill patients but may not be useful markers for the subsequent development of ARDS.