Blood Transfusion

Blood Transfusion
L E U K E M I A
LY M P H O M A
M Y E LO M A

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Table of Contents
Introduction
2
The Blood
3
Red Cells
3
Platelets
4
White Cells
4
Plasma
5
Bone Marrow
5
Preparing Blood Components
7
Safety of Blood Transfusions
9
Autologous and Directed Donations
9
Donor Screening and Collection
9
Testing for Carriers of Infectious Disease
10
Decreasing the Risk of Transmitting Viral Infections
11
Removing White Cells
12
Transfusions for Patients with Leukemia, Lymphoma or Myeloma
13
Transfusion of Red Cells
15
Transfusion of Platelets
16
Transfusion of Granulocytes
17
Transfusion of Plasma and Cryoprecipitate
17
Use of Intravenous Gamma Globulin
18
Transfusion of Albumin
18
Complications of Blood Transfusions
19
Reactions That Damage or Destroy Red Cells
20
Reactions That Cause Fever
20
Reactions That Cause Hives
21
The Patient Makes Antibodies to the Donor’s Blood
21
Transmission of Viral Infections
22
Transmission of Cytomegalovirus (CMV)
23
Transmission of Bacterial Infections
24
Graft Versus Host Disease (GVHD)
24
Effect on A Patient’s Immune System
25
Blood Donation
25
Resources
26
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Introduction
This booklet provides information about blood transfusion for patients with
leukemia, lymphoma or myeloma (blood cancers) and their families. We
welcome your comments on the booklet.
Each year, more than15 million units of whole blood are collected and
nearly five million patients are transfused with blood components in the
United States. (Source: The National Blood Data Resource Center 2001, the
most recent year for which data are available.) On average, each unit is
divided into three different components: red cells, platelets and plasma. Most
of the red cells are transfused to patients undergoing surgical procedures.
However, patients with blood cancers frequently receive platelets and some
red cells. They may require more blood components overall than surgical
patients because their need is likely to continue over a number of weeks or
longer. In addition, most patients who undergo marrow or blood stem cell
transplantation will be transfused.
The most frequently asked questions about blood transfusion relate to:
• The safety of the blood supply;
• Diseases that can be transmitted by blood components; and
• Other complications that may occur following blood transfusion and what
is being done to reduce those risks.
These questions are answered in this booklet.
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The Blood
The blood is the main transport system in the body. It carries raw materials
and finished products from where they originate to where they are used and
transports waste products to disposal sites. Some of the contents are
traveling to a specific destination. For example, sugar (glucose) may be going
from the liver to muscle to provide a source of energy for movement;
coagulation factors may be carried from the liver to a cut blood vessel to
ensure clotting. Other contents are integral parts of blood, such as the red
cells and platelets that perform their functions and spend their mature
existence in the blood.
The blood accounts for about 7 percent of the body weight of a normal
adult. This means that a 154-pound person (70-kilogram average-sized
person) has about 10 pints (or 5 liters) of blood. Smaller adults and children
have proportionately smaller blood volumes. Blood contains red cells,
different types of white cells and platelets. These components are suspended
in the liquid part of blood, called plasma.
Red Cells
The red cells make up about half the volume of blood. They are very
specialized cells that are composed of a disc-like envelope that contains the
red-colored protein hemoglobin, which gives the blood its characteristic color.
Hemoglobin is the protein that picks up oxygen in the lungs and delivers
oxygen to the tissues. It also carries carbon dioxide from the tissues to the
lungs, to be exhaled. The normal red cell lives for 120 days in the circulation,
and so about 1 percent of the body’s red cells (about half an ounce) must
be replaced by the bone marrow each day. The red cell membrane is
composed of protein, fats and carbohydrate molecules that are associated
with the various blood groups. The ABO blood group was described in 1900
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and the Rh blood group in 1945. Transfused red cells should match the
patient’s ABO and Rh blood groups. Many other blood group antigens have
since been described. However, these are not usually matched for
transfusion unless the patient has developed antibodies to these antigens as
a result of previous pregnancies or blood transfusions.
Platelets
The platelets are small fragments of cells that help stop bleeding from
damaged blood vessels. They are present in high concentration in the blood
and circulate for only about 10 days. That means that 10 percent of them
are replaced each day to maintain the platelet count at normal levels.
Platelets function in two ways. One is to stick to damaged surfaces of small
blood vessels and literally plug up any holes that may develop. For example,
when someone has a cut, the blood vessels that carry blood are torn open.
Platelets stick to the torn surface of the vessel, clump together, and plug up
the bleeding site. A firm plug follows. In time, the plug is dissolved and the
vessel wall is repaired and returns to its normal state. The second function of
platelets is to provide a surface that promotes blood clotting.
White Cells
The white cells include neutrophils, eosinophils, basophils, monocytes and
lymphocytes. Neutrophils and monocytes serve as the major defense against
invading bacteria and fungi. They are really tissue cells but because they are
made only in the marrow, they use the blood as a rapid transit system to
carry them to sites of infection. Unlike red cells and platelets, the white cells
are capable of leaving the blood and moving into the tissues where they can
ingest, or eat, bacteria or fungi. This kills the organisms and helps cure the
infection. The neutrophils survive for short periods, less than a day or two,
and thus must be replaced quickly by new cells delivered from the marrow.
Eosinophils and basophils are two additional types of white cells whose roles
are to participate in allergic reactions.
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The lymphocytes are part of the immune system. Most of the lymphocytes in
the body are found in the lymph nodes, the spleen, and a few other
lymphoid organs. They move from one lymphatic organ to another by means
of the lymphatic channels and the circulation. About one billion new
lymphocytes are made each day. There are three major types of
lymphocytes: T cells, B cells and natural killer cells. They make up a complex
immune system that responds to foreign organisms and helps fight cancer.
Plasma
The plasma is the liquid portion of blood that is free of cells. It is composed
primarily of water, in which many chemicals and gases are dissolved. In
addition, there are minerals, carbohydrates, fats, and specialized molecules
such as vitamins, hormones, and enzymes. Plasma also contains specialized
components such as coagulation factors and gamma globulin, which contains
antibodies. Coagulation factors can be removed from plasma and may be
used to treat people with coagulation factor deficiencies, such as hemophilia.
Gamma globulin can be concentrated from plasma and can be used to help
people who lack immune globulins fight infection.
Bone Marrow
Marrow is the spongy tissue where blood cell development takes place. It
occupies the central cavity of bone. All bones have active marrow at birth. By
the time a person reaches young adulthood, the bones of the hands, feet,
arms and legs no longer have functioning marrow. The backbones
(vertebrae), hip, shoulder bones, ribs, breast bones and skull contain
marrow that makes blood cells.
The process of blood formation is called hematopoiesis. Stem cells are a
small group of cells that are responsible for making all the blood cells in the
marrow. Stem cells eventually develop into specific blood cells by a process
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of differentiation. When the fully developed and functional cells have been
formed, they leave the marrow and enter the blood. In healthy individuals
there are sufficient stem cells to keep producing new blood cells
continuously. Some stem cells enter the blood and circulate. They are
present in such small numbers that they cannot be counted or identified by
the usual blood tests. Their presence in the blood is important, because they
can be collected by special techniques called hemapheresis and used for
transplantation in place of stem cells from marrow. This circulation of stem
cells from marrow to blood and back again occurs in the fetus as well. That
is why, after birth, placental and umbilical cord blood can be used as a
source of stem cells for transplantation.
In summary, blood cells are made in the marrow, and when the cells are
fully formed and able to function, they leave the marrow and enter the
blood. The red cells and the platelets perform their respective functions of
delivering oxygen and plugging up injured blood vessels in the circulation.
The neutrophils, eosinophils, basophils, monocytes and lymphocytes, which
together make up the white cells, move into the tissues (for example, the
lungs), where they can combat infections such as pneumonia and perform
their other functions.
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Preparing Blood Components
More than 98 percent of the blood supply in the U.S. comes from volunteer
donors. Most donors give a single unit of whole blood at a site convenient to
their work or home. The availability of plastic containers that can have one or
more satellite bags attached in a completely sterile system allows for
flexibility in preparing the donated blood. Usually three or four blood
components such as red cells, platelets, plasma and cryoprecipitate are
gained from each unit of whole blood donated. “Cryoprecipitate” is the
name for the blood component obtained by freezing plasma and then
thawing it at 4°C. It is used to provide certain clotting factors for people who
need them due to a genetic or acquired defect. The usefulness of
component therapy is that each patient is given only the specific component
that he or she needs. This allows one donation to benefit up to four patients
and conserves precious blood resources. Each component has to be
prepared within a certain time from collection and stored at a specific
temperature and length of time to maintain optimum function. The
availability of plastic bags with attached satellite bags that can be centrifuged
in the lab makes it possible to separate out a variety of different
components. The primary blood bag contains an anticoagulant that prevents
the blood from clotting after it has been collected. This unit is spun gently in
the lab using a centrifuge, which settles the heavier red cells to the bottom
of the bag. The lighter plasma that also contains the platelets can then be
siphoned off into one of the attached satellite bags. A preservative is then
added to the red cells, the tubing is sealed and the red cells are separated
from the other bags. A red cell unit is about 250 milliliters (about 10
ounces) and is stored at 4°C for 42 days. Ideally, the red cells transfused are
the same ABO and Rh type as the patient’s. Certain exceptions are made in
emergencies.
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The bag containing the platelet-rich plasma is then centrifuged at a higher
speed to deposit the platelets at the bottom of the bag along with about 50
milliliters (about two ounces) of plasma. Most of the plasma is siphoned into
a third attached bag. The unit of platelets is sealed and separated, leaving a
bag of plasma. Platelets need to be stored in an incubator at room
temperature and rocked gently. They have a shelf life of only 5 days. About 4
to 5 platelet units of the same ABO type as the patient are pooled together
to make a platelet transfusion for an adult. One unit may be sufficient for an
infant. Cryoprecipitate can be made from the plasma or the plasma can be
stored in a freezer for a year. During this time, it may be used for transfusion
or processed further.
In addition to whole blood donations, some components, such as platelets
or granulocytes, can be collected by hemapheresis. With hemapheresis, a
healthy donor comes into the blood center and his or her blood is drawn
into a machine where the blood is separated into its components. The cell
separator collects only the part of the blood that is needed by the patient
and the rest of the blood is returned to the donor. This allows a much larger
amount of a blood component to be harvested from a single donor. Also,
the donor can be specifically selected or matched with the patient and the
donor can donate more frequently because he or she does not lose red
cells.
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Safety of Blood Transfusions
Autologous and Directed Donations
Autologous donation, in which the patient donates up to 3 units of his or her
own blood to be re-infused later, is possible for healthy patients who are
undergoing a one-time surgery. However, for patients who are being treated
for leukemia, lymphoma or myeloma such donations are not possible
because their own blood lacks adequate numbers of cells.
Some family members ask about “directed donations” in which the family
chooses their own donors for the patient, believing this may be safer.
Although this is possible if a small number of red cells are to be used, e.g.,
for a surgical procedure, there is no evidence that these donations are any
safer than the general blood supply. In fact, under certain circumstances they
may be less safe because related individuals or friends may not wish to
expose a circumstance that makes them unsuitable for donation. For patients
such as those with leukemia, lymphoma or myeloma, the need for long-term
blood support and for specialized components usually makes this approach
unfeasible. Moreover, the consequences of these severe diseases usually
outweigh the concern about blood safety in medically advanced countries.
Donor Screening and Collection
Every patient and physician is concerned about the safety of the blood
supply. The risk of transmitting viral diseases such as HIV and hepatitis by
blood transfusion had dropped dramatically in the last 25 years. This is the
result of a multilayered approach to safety. First, a voluntary blood donor
pool eliminates individuals who might donate for money and not be honest
about their health history. Public education is important so that people know
that certain diseases can be transmitted by blood, what the risk factors are
for carrying infectious agents, and who should refrain from donating because
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