Download Transfusion

In the name of
God
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Presented by:
a.pourhosseini
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Human blood replacement therapy was accepted in the
late nineteenth century. This was followed by the
introduction of blood grouping by Dr. Karl
Landsteiner, who identified the major A, B, and O
groups in 1900. In 1939 Dr. Philip Levine and Dr. Rufus
Stetson followed with the concept of Rh grouping.
These breakthroughs established the foundation from
which the field of transfusion medicine has grown.
Whole blood was considered the standard in
transfusion until the late 1970s, when goal-directed
component therapy began to take prominence. This
change in practice was made possible by the
development of improved collection strategies, testing
for infection, and advances in preservative solutions
and storage.
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Serologic compatibility for A, B, O, and Rh
groups is established routinely. Crossmatching between donors' red blood cells and
recipients' sera (the major cross-match) is
performed. Rh-negative recipients should
receive transfusions only of Rh-negative blood.
However, this group represents only 15% of
the population. Therefore, the administration
of Rh-positive blood is acceptable if Rhnegative blood is not available. However, Rhpositive blood should not be transfused to Rhnegative females who are of childbearing age.
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In emergency situations, type O-negative blood
may be transfused to all recipients. O-negative
and type-specific red blood cells are equally
safe for emergency transfusion. Problems are
associated with the administration of 4 or more
units of O-negative blood, because there is a
significant increase in the risk of hemolysis. In
patients with clinically significant levels of cold
agglutinins, blood should be administered
through a blood warmer. If these antibodies are
present in high titer, hypothermia is
contraindicated.
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In patients who have been transfused multiple
times and who have developed alloantibodies
or who have autoimmune hemolytic anemia
with pan–red blood cell antibodies, typing and
cross-matching is often difficult, and sufficient
time should be allotted preoperatively to
accumulate blood that might be required
during the operation. Cross-matching should
always be performed before the administration
of dextran, because it interferes with the typing
procedure.
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The use of autologous transfusion is growing. Up
to 5 units can be collected for subsequent use
during elective procedures. Patients can donate
blood if their hemoglobin concentration exceeds 11
g/dL or if the hematocrit is >34%. The first
procurement is performed 40 days before the
planned operation and the last one is performed 3
days before the operation. Donations can be
scheduled at intervals of 3 to 4 days.
Administration of recombinant human
erythropoietin accelerates generation of red blood
cells and allows for more frequent harvesting of
blood.
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Banked whole blood, once the gold standard, is rarely
available. The shelf life is now around 6 weeks. At least 70%
of the transfused erythrocytes remain in the circulation for
24 hours after transfusion and are viable. The age of red cells
may play a significant role in the inflammatory response
and incidence of multiple organ failure. The changes in the
red blood cells that occur during storage include reduction
of intracellular ADP and 2,3-diphosphoglycerate, which
alters the oxygen dissociation curve of hemoglobin and
results in a decrease in oxygen transport. Although all
clotting factors are relatively stable in banked blood except
for factors V and VIII, banked blood progressively becomes
acidotic with elevated levels of lactate, potassium, and
ammonia. The hemolysis that occurs during storage is
insignificant.
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Fresh whole blood refers to blood that is
administered within 24 hours of its donation.
Advances in testing for infectious disease now
make fresh whole blood another option. Recent
evidence has shown that the use of fresh whole
blood may improve outcomes in patients with
trauma-associated coagulopathy in the combat
situation, and a civilian study will soon be
under way. An advantage to the use of fresh
whole blood is that it provides greater
coagulation activity than equal units of
component
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Packed red blood cells are the product of choice for
most clinical situations. Concentrated suspensions of
red blood cells can be prepared by removing most of
the supernatant plasma after centrifugation. This
preparation reduces, but does not eliminate, reaction
caused by plasma components. It also reduces the
amount of sodium, potassium, lactic acid, and citrate
administered. Frozen red blood cells are not available
for use in emergencies. They are used for patients who
are known to have been previously sensitized. By
freezing red blood cells viability is theoretically
improved, and the ATP and 2,3-diphosphoglycerate
concentrations are maintained. Little clinical outcome
data are available to substantiate these findings.
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Leukocyte-reduced and leukocytereduced/washed red blood cell products are
prepared by filtration that removes approximately
99.9% of the white blood cells and most of the
platelets (leukocyte-reduced red blood cells), and if
necessary, by additional saline washing
(leukocyte-reduced/washed red blood cells).
Leukocyte reduction prevents almost all febrile,
nonhemolytic transfusion reactions (fever and/or
rigors), alloimmunization to HLA class I antigens,
and platelet transfusion refractoriness as well as
cytomegalovirus transmission. In most western
nations, it is the standard red blood cell
transfusion product.
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Opponents of universal leukoreduction believe
that the additional costs associated with this
process are not justified because they are of the
opinion that transfused allogenic white blood cells
have no significant immunomodulatory effects.
Supporters of universal leukocyte reduction argue
that allogenic transfusion of white cells
predisposes to postoperative bacterial infection
and multiorgan failure. Reviews of randomized
trials and meta-analysis have not provided
convincing evidence either way, although a large
Canadian retrospective study suggests a decrease
in mortality and infections when leukocytereduced red blood cells are used.
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The indications for platelet transfusion include
thrombocytopenia caused by massive blood
loss and replacement with platelet-poor
products, thrombocytopenia caused by
inadequate platelet production, and qualitative
platelet disorders. The shelf life of platelets is
120 hours from time of donation. One unit of
platelet concentrate has a volume of
approximately 50 mL. Platelet preparations are
capable of transmitting infectious diseases and
can provoke allergic reactions similar to those
caused by blood transfusion.
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Therapeutic levels of platelets reached after
therapy are in the range of 50,000 to 100,000/μL.
However, there is a growing body of information
suggesting that platelet transfusion thresholds can
safely be lowered in patients who have no signs of
hemostatic deficiency and who have no history of
poor tolerance to low platelet counts. Prevention of
HLA alloimmunization can be achieved by
leukocyte reduction through filtration. In rare
cases, such as in patients who have become
alloimmunized through previous transfusion or
patients who are refractory from sensitization
through prior pregnancies, HLA-matched platelets
can be used.
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Fresh-frozen plasma (FFP) prepared from freshly
donated blood is the usual source of the vitamin
K–dependent factors and is the only source of
factor V. However, FFP carries infectious risks
similar to those of other component therapies. FFP
has come to the forefront with the inception of
damage control resuscitation in patients with
trauma-associated coagulopathy. In an effort to
increase the shelf life and avoid the need for
refrigeration, lyophilized plasma is being tested.
Preliminary animal studies suggest that this
process preserves the beneficial effects of FFP.
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Technologic advancements have made the
majority of clotting factors and albumin readily
available as concentrates. These products are
readily obtainable and carry no inherent
infectious risks as do other component
therapies.
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Human polymerized hemoglobin (PolyHeme) is a
universally compatible, immediately available,
disease-free, oxygen-carrying resuscitative fluid
that has been successfully used in massively
bleeding patients when red blood cells were not
transfused. Advantages of an artificial oxygen
carrier include the absence of blood-type antigens
(no cross-match needed) and viral infections and
long-term stability, which allows prolonged
periods of storage. Disadvantages include shorter
half-life in the bloodstream and the potential to
increase cardiovascular complications. This
product has not yet been approved for use in
patients.
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1) Improvement in Oxygen-Carrying Capacity
2)Treatment of Anemia: Transfusion Trigger
3)Volume Replacement
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A healthy adult can lose up to 15% of total blood
volume (class I hemorrhage or up to 750 mL) with
only minor effects on the circulation. Loss of 15 to
30% of blood volume (class II hemorrhage or 750
to 1500 mL) is associated with tachycardia and
decreased pulse pressure but, importantly, a
normal blood pressure. Loss of 30 to 40% (class III
hemorrhage or 1500 to 2000 mL) results in
tachycardia, tachypnea, hypotension, oliguria, and
changes in mental status. Class IV hemorrhage is
loss of >40% of blood volume and is considered
life-threatening.
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Current resuscitation algorithms are based on
the sequence of crystalloid followed by red
blood cells and then plasma and platelet
transfusions and have been in widespread use
since the 1970s. Recently, the damage control
resuscitation (DCR) strategy, aimed at halting
and/or preventing rather than treating the
lethal triad of coagulopathy, acidosis, and
hypothermia, has challenged traditional
thinking on early resuscitation strategies.
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In civilian trauma systems nearly half of all deaths occur before a
patient reaches the hospital, and few of these deaths are
preventable. Those patients who survive until arrival at an
emergency center have a high incidence of truncal hemorrhage,
and deaths in this group of patients may be potentially
preventable. Truncal hemorrhage patients in shock often present
with the early coagulopathy of trauma in the emergency
department and are at significant risk of dying.
Many of these patients receive a massive transfusion, generally
defined as the administration of 10 or more units of packed red
blood cells within 24 hours of admission. Although 25% of all
trauma patients admitted receive a unit of blood early after
admission, only a small percentage of patients receive a massive
transfusion. In the military setting, however, the percentage of
patients receiving a massive transfusion almost doubles.
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Nonhemolytic Reactions
Allergic Reactions
Respiratory Complications
Hemolytic Reactions
Transmission of Disease
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Malaria,Chagas' disease, brucellosis, and, very
rarely, syphilis,CMV
hepatitis C virus and HIV-1
Hepatitis A virus
other pathogens, such as West Nile virus
Prion disorders (e.g., Creutzfeldt-Jakob
disease)