tailieunhanh - Chapter 107. Transfusion Biology and Therapy (Part 4)

Apheresis technology is used for the collection of multiple units of platelets from a single donor. These single-donor apheresis platelets (SDAP) contain the equivalent of at least six units of RD platelets and have fewer contaminating leukocytes than pooled RD platelets. Plasma may also be collected by apheresis. Plasma derivatives such as albumin, intravenous immunoglobulin, antithrombin, and coagulation factor concentrates are prepared from pooled plasma from many donors and are treated to eliminate infectious agents. Whole Blood Whole blood provides both oxygen-carrying capacity and volume expansion. . | Chapter 107. Transfusion Biology and Therapy Part 4 Apheresis technology is used for the collection of multiple units of platelets from a single donor. These single-donor apheresis platelets SDAP contain the equivalent of at least six units of RD platelets and have fewer contaminating leukocytes than pooled RD platelets. Plasma may also be collected by apheresis. Plasma derivatives such as albumin intravenous immunoglobulin antithrombin and coagulation factor concentrates are prepared from pooled plasma from many donors and are treated to eliminate infectious agents. Whole Blood Whole blood provides both oxygen-carrying capacity and volume expansion. It is the ideal component for patients who have sustained acute hemorrhage of 25 total blood volume loss. Whole blood is stored at 4 C to maintain erythrocyte viability but platelet dysfunction and degradation of some coagulation factors occurs. In addition 2 3-bisphosphoglycerate levels fall over time leading to an increase in the oxygen affinity of the hemoglobin and a decreased capacity to deliver oxygen to the tissues a problem with all red cell storage. Whole blood is not readily available since it is routinely processed into components. Packed Red Blood Cells This product increases oxygen-carrying capacity in the anemic patient. Adequate oxygenation can be maintained with a hemoglobin content of 70 g L in the normovolemic patient without cardiac disease however comorbid factors often necessitate transfusion at a higher threshold. The decision to transfuse should be guided by the clinical situation and not by an arbitrary laboratory value. In the critical care setting liberal use of transfusions to maintain near-normal levels of hemoglobin may have unexpected negative effects on survival. In most patients requiring transfusion levels of hemoglobin of 100 g L are sufficient to keep oxygen supply from being critically low. PRBCs may be modified to prevent certain adverse reactions. Leukocyte reduction of cellular .