- It is common to underestimate quantitative blood loss in the setting of trauma. Careful and frequent monitoring of vital signs and hematocrit is critical in the detection of severe hemorrhage.
- Massive transfusion protocols exist to supply O-negative blood and other essential blood products for the resuscitation of the hemodynamically unstable trauma patient.
- Mild to severe reactions can occur during the transfusion process including fever, chills, nausea, hypotension, or shock. Whether this is caused by blood type incompatibility, antibodies to donor cells, or blood product contamination, the transfusion must be stopped immediately and the symptoms of the reaction treated aggressively.
Transfusion of blood and blood components is often necessary in the emergency department (ED). Whole blood, packed red blood cells (PRBCs), platelets, granulocytes, fresh frozen plasma, cryoprecipitate, specific clotting factors, albumin, and immunoglobulins each have specific indications and risks associated with their use. As blood for transfusion is a scarce commodity, the component that will specifically address the patient's need is generally transfused.
Transfusion of whole blood is rarely performed but may be indicated for prompt restoration of red cells and volume after trauma or surgery. After 24 hours of storage, platelets and granulocytes contained within whole blood have lost function. Activity of labile clotting factors V and VIII is also diminished greatly within 3 to 5 days. The risk of transfusion reactions with whole blood is doubled owing to the volume of foreign proteins and antibodies that it contains.1
PRBC units contain approximately 30 to 50 mL of plasma and have a hematocrit ranging from 55% to 80%, depending on the preservative used for storage. Units are stored in solution with anticoagulant and preservative for up to 42 days. There are no functional platelets or granulocytes in this preparation. For patients with a previous history of febrile reactions to transfusions or if the risk of cytomegalovirus (CMV) transmission is to be particularly avoided, filtered, leukocyte-poor red cells are recommended. Leukocyte depleted preparations contain <107 leukocytes per unit. In many institutions all PRBC units are routinely leukocyte depleted.2
Platelet concentrates are obtained by either pooling multiple individual platelet concentrates from approximately four to eight individual whole blood donors (commonly known as a “6-pack”) or from plateletpheresis of a single donor. There may be advantages to the reduced donor exposure of single donor product; however, platelet product choice varies by institution and availability. Both preparations contain approximately 5.5 × 1010 platelets in approximately 50 mL of plasma. They should be ABO and Rh compatible, but crossmatching is not necessary. In children, the dose is estimated at 0.1 to 0.2 U/kg of random donor platelets required to raise the platelet count by 50 000 to 100 000/μL. Platelet transfusions are indicated for patients with thrombocytopenia or platelet dysfunction who are actively bleeding. Counts above 20 000/μL rarely result in spontaneous bleeding, but at counts below 10 000/μL, the risk is severe. Patients with immune thrombocytopenia or thrombotic thrombocytopenic purpura ...