WHAT A HEALTH
PROVIDER SEES
Artificial Blood
W
ith the risks of bloodborne diseases, such as
human immunodeficiency virus (HIV) and hep-
atitis B, many hospitals, clinics, and blood banks
are experiencing a shortage of available blood for
transfusions. Another challenge is that blood has a
relatively short useful shelf life (less than 120 days),
after which time it must be thrown away. To counter
these problems, some pharmaceutical companies
have developed artificial blood (a.). Artificial blood
must be osmotically compatible with real blood
and must have a high carrying capacity for oxygen
and carbon dioxide. Two types have been devel-
NORTHFIhLD
LABORATORIES
INC
Г» I
Red blood cell (RBC)
(7 urn)
Hemoglobin-based
oxygen carrier (HBOC)
(0.08-0.1 ц m)
\
Perfluorocarbon (PFC)
(0.2 urn)
oped for testing. One type uses hemoglobin-based oxygen carriers (HBOCs),
forms of hemoglobin that are chemically modified to prevent degradation by
macrophages (see Figure 10.6). The other type uses perfluorocarbons (PFCs),
fluorine-based organic compounds. Both types of artificial blood can carry
oxygen and carbon dioxide efficiently. Their components are also smaller than
RBCs, so they can reach into small vessels more easily (b.). Both types are be-
ing evaluated in clinical trials for their effectiveness compared to whole blood
transfusions as well as possible side effects. Some reported side effects of
HBOCs include abdominal cramping and elevated blood pressure. If approved
for medical use, artificial blood would be especially helpful in trauma centers,
on battlefields, and during surgical procedures.
Think Critically»
1.
H ow w ould artificial blood im prove
the storage of blood for transfusions?
2.
In certain traum a and battle situations, there is little
tim e to type the patient's blood before givin g a transfu-
sion. Som etim es the blood is adm inistered, and the health
provider hopes that he or she has m ade a proper selec-
tion so there will not be a transfusion reaction. W ould it
be more likely that an individual w ould have a transfusion
reaction to real blood or to artificial blood? Explain.
Similar antigen-antibody reactions occur with the
Rh blood group, or Rh factor, which was named for the
rhesus monkey, where it was first found. People are said
to be either Rh-negative (not have Rh factor) or Rh-pos-
itive (have Rh factor). This blood antigen must also be
carefully matched during a transfusion. When selecting
donor blood for a transfusion, one must be careful to en-
sure that no “new” antigens are being given to the recipi-
ent. For example, if you are an Rh-negative individual,
you cannot receive Rh-positive blood because you would
be getting a new antigen (Rh factor). Foreign antigens
can stimulate a transfusion reaction that can sometimes
be fatal.
Researchers are attempting to address the challeng-
es of blood group compatibility in their efforts to develop
artificial blood (see
W h a t a H e a lth P ro vid er S ee s).
298 CHAPTER 10
The Cardiovascular System: Blood
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