SPECIAL SITUATIONS INVOLVING TRANSFUSION
a. Massive Transfusion.
(1) Massive transfusion can be defined as transfusion of the patient's blood
volume during a 12-hour interval. The effects of massive transfusion upon the recipient
may be due to the biochemical and functional characteristics of stored blood:
Platelets deteriorate during storage of WB.
(b) Coagulation Factors V and VIII deteriorate during storage of WB.
(c) The oxygen saturation curve of hemoglobin shifts and oxygen is
less readily released to the tissues.
(2) Transfusion of large amounts of blood depleted of platelets and Factors
V and VIII may create deficiencies in the recipient because of dilution of the recipient's
blood with this depleted stored blood. However, usually Factor VIII is rapidly replaced
by the patient and Factor V levels do not fall below that needed for hemostasis. In
addition, the hemostatic process that occurs in the bleeding patient consumes the
patient's own platelets and coagulation factors and compounds the depletion state.
Oxygen delivery by transfused cells stored more than two weeks in CPD may be
diminished immediately following transfusion, but oxygen release improves
approximately 24 hours following transfusion.
(3) Patients undergoing massive transfusions should be followed closely
with coagulation studies, including a platelet count. If coagulation abnormalities or
thrombocytopenia develop, these deficiencies should be replaced with the appropriate
blood components. It is usually not possible to correct these deficits with fresh WB.
Fresh-frozen plasma, platelet concentrates, and RBCs will also be more readily
available than fresh WB. Coagulation Factor IX concentrates should not be used in
these situations (see above).
(4) Despite dilution of the patient's blood with donor plasma, continued
compatibility-testing is recommended. If it is necessary to change to a different blood
group in massive transfusion, the patient's history and clinical situation should be
considered, as well as the potential blood supply. It is sometimes more desirable to
switch Rh types (for instance from Rh-negative to Rh-positive) than to switch ABO
group. However, age and sex may also be important to consider. For example, when
transfusing a young, Rh-negative woman, it is usually preferable to switch ABO groups,
if feasible, before switching Rh.