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BLOOD
TRANSFUSION DETAILS
Contents:
Why you may need blood transfusion
Who needs blood transfusion
Autologous (own blood)
transfusion , risks and benefits
Allogenic (alien blood)
transfusion, risks and benefits
1
Why will the patient need a blood transfusion
(A little common sense theory)
When considering the blood loss during surgery and its
replacement, you must distinguish between two different effects of blood loss. The blood
loss affects
1) the oxygen carrying capacity of blood and it also
affects
2) the capacity of blood to perfuse (circulate through)
important organs in the body.
1) Oxygen carrying capacity of the blood
If the blood loss caused a severe drop in the level of of
hemoglobin ( usually under 100 g/Lt) then the transport of sufficient quantity of oxygen
from lung to important organs (heart, kidneys) may be jeopardised. This is more likely to
happen in patients who preoperatively have had low concentrations of hemoglobine.
In these patients it is important to increase the level of
hemoglobin in their blood to secure the transport of sufficient quantity of oxygen to the
important organs. The anaesthesiologist / surgeon must replace the hemoglobin loss by
blood transfusion.
The patient in this case will receive one or more units of
blood transfusion; every such unit corresponds to 225 to 300 ml of concentrated red blood
cells (erythrocytes) suspended in blood plasma, anticoagulants (substances that prevent
the blood to congeal) and other substance to increase the shell life of stored blood to 42
days.
2) The perfusion capacity of the blood
When there has been severe loss of blood volume during
surgery, the remaining blood may still have sufficient concentration of hemoglobin
to carry oxygen to the important organs, but the volume of the remaining blood may be just
too small to perfuse these organs effectively. This often happens in patients who have had
preoperatively high concentration of hemoglobin ( > 150 g/Lt).
In this case it suffices if the the anaesthesiologist /
surgeon expands the volume of blood with blood expanding liquids, the simplest such liquid
is physiological solution (0,9% salt solution in water). The expanded blood volume will
guarantee sufficient transport of oxygen. Blood transfusion should not be used to expand
the quantity of circulating blood only. (Lemos 1996)
2
Indications for transfusion (who needs transfusion)
At present there are no generally accepted,
all-encompassing rules to decide which patient will need blood transfusion during and
after the total joint surgery. Decision to order blood transfusion involves multiple
factors. According to the traditional rule, originating in 1942 (!), transfusion is
recommended when the level of hemoglobin is less than 110 g/Lt.
This rule has been questioned, because the hemoglobin level
cannot be a static number. Much depends on the preoperative level and the suddenness of
the drop in the hemoglobin kevel. The decision rules regarding transfusion must also
include an assessment of the patient’s symptoms, not only his /her laboratory values.
Symptoms of low hemoglobin level are shortness of breath,
quick pulse not responding to infusion of blood expanders, angina (heart ache), dizziness,
postural hypotension (drop of blood pressure when raising up), excessive fatigue.
3
Autologous transfusion, benefits and risks
In the 1960 and 1970's many units of allogenic blood and
blood plasma were contaminated with HIV and hepatitis viruses. Many patients who needed
blood transfusions often (haemophiliacs) or children who needed blood transfusion during
spinal operations were the first innocent victims of this epidemic.
Preoperative donation of autologous blood as a means to
eliminate this risk was introduced first for adolescent patients operated on for spinal
deformity.
Fears of transmission of HIV virus and viral hepatitis
triggered the use of autologous transfusions in patients operated on with total joints
too.
Despite markedly decreased risks of viral contamination of
the current allogenic blood supply, the patients and the surgeons still strongly prefer
the use of autologous blood in total joint surgery.
There are as yet no conclusive studies determining which
total joint patients are likely to benefit from pre-donation of autologous blood.
The lack of such studies has two consequences:
1) too many patients who will not need transfusion during /
after surgery still donate their blood preoperatively. The blood of these patients is
discarded, increasing the costs of the autologous blood donations.
2) Preoperative blood donation usually lowers hemoglobin
levels with 9 - 12 g/Lt, causing even mild anaemia in some of them. Lower hemoglobin level
will increase the risk that these patient will need transfusion (albeit of their own
blood). . Because the autologous blood transfusion has its risks too, the donor patients
are exposed unnecessarily to these risks. Again a "moment 22" situation.
Benefits of autologous blood donation
1 ) The donor patients (patients who
donated their blood before the surgery) have three to five times lower risk to get
allogenic (alien) blood transfusion then the nondonor patients (the patients who did not
donate their blood before the surgery)
PER CENT OF PATIENTS WHO RECEIVED ALLOGENIC BLOOD
| Type of operation |
Nondonors |
Donors |
| Primary total hip / knee |
15 % |
3 % |
| Bilateral or revision total hip
/ knee |
49 % |
19 % |
(Hatzidakis 2000)
2 ) The donor patients who receive only
their own (autologous) blood will escape all the risks associated with the transfusion of
allogenic (alien) blood. ( See later)
Disadvantages / risks of autologous blood
donation
Collection of autologous blood from the patient is
not problem-free.
Most important risk pertains to the fact, that donating
your blood lowers your hemoglobine level by 9 to 12 g/Lt. Lower hemoglobin level will
increase the risk that you will need transfusion of your blood ( a " moment 22"
situation).
Multiple phlebotomies (sticks in the vein) are painful,
time-consuming, and the treatment with iron afterwards causes bowel problems.
Sudden drop of blood pressure, severe muscle convulsions,
heartache (angina), inflammation and severe damage of the veins occur in 2 to 5 per cent
of patients during blood donation procedure. In 0,006 % of cases, these complications
necessitated a hospital stay. Extremely rare risk, but it is still present.
Disadvantages / risks of autologous blood
transfusion
It may surprise you, that transfusion of your own blood
entails also risk of complications
Most often observed reaction is a febrile reaction to the
autologous transfusion, which occurs in about 2 to 4 % of all such transfusions, but on
rare occasions ( 0,01 % of all cases) there may occur also more severe reactions.
Who should be observant:
More prone to these reactions are women weighting <55 kg
(110 pounds), people with previous reaction to transfusion, and people with coronary
artery disease.
Human (clerk) error also applies to autologous transfusion
- you may get an incorrect blood unit destined for another patient. This happens in 0,
003% to 0, 0006 % of all autologous transfusions. Again, this risk is very small but it
exists.
Why is the not transfused autologous blood
discarded
When you donate your own blood, the blood bank uses fewer
strict criteria to accept you as donor of autologous blood. Among them, your hemoglobin
level should be > 110 g/Lt only, whereas for allogenic donors the hemoglobin this level
is >125 g/Lt. Testing for transmissible diseases may be less strict or entirely absent
for donors of autologous blood.
So it is safe to discard the non-used autologous blood. It
is again a " moment 22" situation . The less strict criteria for autologous
blood donation are used to make it cheaper. But because so many unit of autologous blood
are discarded, the autologous blood is actually more expensive than the allogenic blood.
Incidentally, autologous donors who fulfill the more strict
criteria valid for allogenic donors have only half so many complications after transfusion
of their own blood compared with people who donated their blood according to the relaxed
criteria.
4
Disadvantages and complications of allogenic
transfusion.
Transmission of diseases
It is the most feared risk associated with the transfusion
of allogenic blood.
Although the HIV virus is the most feared, the risk of
contracting hepatitis (liver inflammation) from allogenic transfusion is far greater than
that of contracting HIV. In one report the risk of death from hepatitis C was 98 times
greater than the risk to die by HIV infection contracted by allognic blood transfusion
RISKS ASSOCIATED WITH ALLOGENIC TRANSFUSION
| Complication |
Prevalence per cent |
| Any transfusion reaction |
5 % |
| Fever or urticaria |
0,03 % |
| Non lethal hemolytic reaction |
0,004% |
| Lethal hemolytic reaction |
< 0,0001% |
| Transmission of HIV |
0,0002 % |
| Transmission of hepatitis C
virus |
0,002 % |
| Postoperative infection,
increase of risk |
20 % (?) |
(Lemos 2000)
Febrile response :
Fever is usually associated with chills, general
discomfort, or even severe pain. It occurs more often as reaction to white blood cells
transfused together with red blood cells. In very rare cases it may be caused by bacterial
contamination of the blood.
Allergic or immune reaction:
This reaction consists of fever, chills, and urticaria
(nettle). The first allogenic transfusion may go undetected and make the patient sensitive
for further such transfusions that then produce severe allergic reaction.
Hemolysis
Hemoglobin, the dye contained in the red blood cells, is a
very dangerous substance when it escapes from the red blood cells and circulates freely in
the blood. This state is called hemolysis.
The free molecules of hemoglobin circulating in the blood
clog the kidneys. This is a very serious complication caused by transfusion of wrong blood
group blood.
The symptoms are fever, chills, chest pain, sudden blood
pressure fall, occurrence of hemoglobin in the urine ( if the patient produces any urine
at all)
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References
Hatzidakis AM et al. J Bone Joint Surg-Am, 2000; 82-A: 89 -
100
Lemos MJ et Healy WL . J Bone Joint Surg-Am, 1996; 78-A:
1260 - 1270
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