Chapter 30: Blood Transfusion

Blood Transfusion exploration of transfusion medicine details the essential protocols for transferring blood components securely between individuals while adhering to strict regulatory standards. It highlights the critical importance of donor selection, which involves rigorous health questionnaires regarding lifestyle and travel, as well as clinical screenings for hemoglobin levels and weight to protect both the donor and the recipient. To maintain a safe blood supply, all donations undergo mandatory testing for infectious agents such as HIV, hepatitis B and C, and syphilis. The fundamental principles of immunohematology are examined, focusing on the ABO and Rh blood group systems where the presence or absence of specific antigens determines compatibility. The text explains how naturally occurring IgM antibodies or immune-mediated IgG antibodies can trigger severe reactions if mismatched blood is administered. It elaborates on laboratory procedures used to prevent these issues, including the direct and indirect antiglobulin (Coombs') tests and cross-matching, which ensure that donor cells will not be attacked by the recipient's immune system. Beyond basic red cell replacement, the summary covers the specific clinical uses of various components like platelets, fresh frozen plasma, and cryoprecipitate, as well as the benefits of leucodepletion—filtering out white cells—to prevent febrile reactions and the transmission of certain viruses. Special attention is given to managing transfusion-related risks, ranging from immediate hemolytic shock and transfusion-related acute lung injury (TRALI) to delayed complications like iron overload in patients receiving chronic therapy. Additionally, the chapter discusses modern strategies to reduce blood usage, including the use of recombinant growth factors and autologous techniques like intraoperative cell salvage, providing a holistic view of current clinical practices in hematology. For patient safety, the leucocyte count in filtered products must be (lesser than) 5 x 10^6/L.