(2) Packed red blood cells. Packed red blood cells have 75 percent of the
plasma removed in the laboratory. This preparation is frequently used where the patient
needs the oxygen-carrying capacity of the erythrocytes, but would not benefit from the
extra fluid or the small amount of protein in the plasma. In many chronic diseases, a
further expansion of the plasma volume can cause heart failure. The packed red blood
cells also tend to cause less plasma transfusion reactions from donor antibodies. It is
safer to use type O Negative packed red blood cells than whole blood when there is no
time for cross-match.
b. Plasma. Plasma (or other blood fraction) products are made either from
whole blood or from some other process that leaves part of the blood behind. Some
examples of these are:
Whole plasma. Whole plasma may be a by-product from the
preparation of packed red blood cells, made from blood a few days before the expiration
date on the blood unit or drawn by plasmapheresis. Plasma is used as fluid
replacement caused by hemorrhage, burns, or in other situations where blood volume
must be increased without replacement of blood proteins.
(2) Cryoprecipitate. To make cryoprecipitate, fresh frozen plasma (FFP) is
first thawed at 4C until all ice is melted. Then the cold insoluble fraction of plasma
protein is recovered by centrifugation. The product is used for patients with hemophilia.
Cryoprecipitate can be stored for two years at -20 C (20 degrees below 0 Celsius).
(3) Platelet rich plasma. Platelet rich plasma is used in the treatment of
some forms of malignancy. This product may be effective in controlling serious active
bleeding, especially in surgery. Because of the short survival rate of platelets, the
product has limited use. A-B-O group type match is required. No cross-match of other
factors is required prior to platelet transfusion unless the platelet product contains many
red blood cells. This does not apply to the platelet rich plasma since the plasma itself
may carry antibodies.
c. Plasma Expanders. Plasma expanders are used to treat or prevent acute
and severe fluid loss due to trauma or surgery. These products are usually used
instead of whole blood in emergency-situations in which whole blood is not available.
Below are examples of plasma expanders.