Uses of Blood Transfusion
are used to treat blood loss or to supply blood components that your body
cannot make for itself.
Treating blood loss
Blood loss may result from
injury, major surgery, or diseases that destroy
red blood cells or
platelets, two important blood components. If too much
blood is lost (low blood volume), your body cannot maintain a proper blood
pressure, which results in
shock. Blood loss can also reduce the number of
oxygen-carrying red blood cells in the blood, which may prevent enough oxygen
from reaching the rest of the body.
Whole blood is rarely given
to treat blood loss. Instead, you are given the blood component you most need.
If you have lost too many red blood cells or are not making enough of them, you
are given packed red blood cells. If you have low blood volume, you are given
plasma and/or other fluids to maintain blood pressure.
If you have lost a great deal of blood, or if your
clotting factors or platelets are low or abnormal, you
may also need a transfusion of either of these to help control bleeding.
Sometimes you may need replacements of some blood substances if your body does
not make enough of them. For example, you may be given substances to help your
blood clot (clotting factors) if you do not have enough of them
Blood lost during surgery sometimes can be recovered,
cleaned, and returned to you as a transfusion. This greatly reduces the amount
of blood you might otherwise need to receive. Receiving your own blood back is
safer, because there is no chance of a reaction.
Replacing or supplementing blood components
component that affects the blood's ability to clot is platelets. A reduced
number of platelets (thrombocytopenia) or the failure of
platelets to function properly increases the time it takes for bleeding to stop
(increased bleeding time). Transfusion with platelets improves the clotting
time, which reduces the risk of uncontrolled bleeding. This treatment does not cure
the cause of platelet loss.
Anemia is a
decrease in the number of oxygen-carrying red blood cells or a decrease in the
hemoglobin, the oxygen-carrying substance in the red
blood cells. There are several types of anemia, each with a different cause,
and each is treated differently. Severe anemia may be treated with a
transfusion of packed red blood cells. This temporarily increases the
number of oxygen-carrying red blood cells in circulation and may improve
symptoms, but it does not treat the cause of the anemia.