Blood Products
There are a variety of blood products, pharmacologic agents, and procedures that can be utilized to
treat anemia, thrombocytopenia, and bleeding disorders. Here is a brief overview of the products and
services available:
Product Description
Packed red blood cells (PRBCs) are made from a unit of
whole blood by centrifugation and removal of most of the
plasma, leaving a unit with a hematocrit of about 60%. One
PRBC unit will raise the hematocrit of a standard adult patient
by 3% (or about 1%/mL/kg in a child - 12%/25 kg with the
standard 300 mL PRBC unit). PRBCs are used to replace red
cell mass when tissue oxygenation is impaired by acute or
chronic anemia.
FFP contains all factors of the soluble coagulation system,
including the labile factors V and VIII. FFP is indicated when
a patient has MULTIPLE factor deficiencies and is
BLEEDING. Note that FFP SHOULD NEVER be used as a
plasma expander.
Cryoprecipitate (cryo) contains a concentrated subset of FFP
components including fibrinogen, factor VIII coagulant,
vonWillebrand factor, and factor XIII. Cryoprecipitate is used
for hypofibrinogenemia, vonWillebrand disease, and in
situations calling for a "fibrin glue." Cryo IS NOT just a
concentrate of FFP. In fact, a unit of cryo contains only 40-
50% of the coag factors found in a unit of FFP, but those
factors are more concentrated in the cryo (less volume).
A single platelet unit is derived from one whole blood unit
collected. Platelets are stored at room temperature and
CANNOT be frozen. They must be used in 5 days. Pooled
platelets from multiple donors from whole blood collections
are cheaper to produce but the exposure to the recipient
increases.
A "six pack" of platelets can be obtained by apheresis from a
single donor at one time. Thus, apheresis platelets give just
"one donor" exposure to the recipient, but the cost is high. The
recipient's HLA type can be "matched" to a platelet donor with
a similar HLA type to deal with problems of HLA
alloimmunization (in patients with prior transfusions or
pregnancies). The expected incremental increase in platelet
count for adults is 30 - 60 K for each "six pack" of platelets
Normal saline is used when providing vascular access and
fluid volume when transfusing other products and
pharmacologic agents. Normal saline is more readily
accessible than albumin or FFP, it is relatively inexpensive,
and it does not have the risk of viral transmission.
Albumin is useful as a plasma expander. Albumin is not
always readily accessible and it is expensive, but it does not
have risk of viral transmission.
Apheresis involves removal of whole blood from either a
patient undergoing treatment or a donor who is providing a
blood component (typically platelets). Using an instrument
designed as a centrifuge, the components of whole blood are
separated. One of the separated portions is withdrawn and the
remaining components are retransfused. The components
which are separated off and withdrawn include: plasma
(plasmapheresis), platelets (plateletpheresis), and leukocytes
(leukapheresis).
Indications for Blood Product Usage
There are situations identified in which blood products may be needed:
Packed RBCs: generally indicated with a hemoglobin of 7 to 8 g/dL, a markedly
decreased oxygen saturation and/or orthostatic hypotension. There is indication that the
patient needs additional oxygen carrying capacity.
Platelets: generally indicated for a platelet count of less than 50,000/microliter and there
is active bleeding, or if a procedure such as surgery is to be performed. Spontaneous
bleeding is unlikely until the platelet count drops below 10,000 to 20,000/microliter.
FFP: generally indicated when a patient has multiple factor deficiencies and is bleeding,
or for thrombotic thrombocytopenic purpura (TTP). The PT and PTT will be prolonged,
and the INR generally should be greater than 1.6.
Cryo: generally indicated for hypofibrinogenemia, vonWillebrand disease, and in
situations calling for a "fibrin glue."
There are specialized blood products for situations in which cells or substances in the unit need to
be reduced or removed:
Product Description
A unit of packed red blood cells (PRBCs) is washed to reduce
plasma proteins. This reduces the risk for allergic transfusion
Washed Red Blood Cells reactions. Washing reduces immunoglobulins, such as anti-
IgA that could cause anaphylactic transfusion reactions in
persons with selective IgA deficiency.
Red blood cell and platelet units may be filtered to remove
most of the leukocytes (white blood cells). This may reduce
Leukocyte Reduction the risk for febrile transfusion reactions, may help prevent
alloimmunizaton to MHC (HLA) donor antigens, and help
reduce the risk for cytomegalovirus (CMV) infection.
Irradiation is needed to destroy all living leukocytes (white
Irradiated Blood blood cells), particularly lymphocytes that could cause
transfusion associated graft versus host disease (TAGVD).
