3. Major Functions of Blood
Respiration
Nutrition
Excretion
Coagulation
Maintenance of normal
acid base balance in the
body
Regulation of body
temperature by the
distribution of body heat
Regulation of water
balance through the
effects of blood on the
exchange of water
between the circulating
fluid and the tissue fluid
Defence against infection
Transport of hormones
and regulation of
metabolism
Transport of metabolites
4. ARTIFICIAL BLOOD
Artificial Blood (also called Blood Substitute or Blood Surrogate) is a
substance used to mimic and fulfill some functions of biological blood.
It aims to provide an alternative to blood transfusion, which is transferring
blood or blood-based products from one person to another.
8. HISTORY
YEAR EVENTS
1616 Wiliam Harvey described how blood is circulated throughout the body.
1667 First successful Human Blood Transfusions.
Medical practitioners tried substances like Beer, Urine, Milk, Plant resins,
Sheep blood etc. as substituents
1854
Milk was one of the first used material injected in patients to treat Asiatic
Cholera. Physicians believed that the milk helped regenerate white blood
cells. However, many practitioners remained sceptical so milk injections
never found widespread appeal, so soon discarded.
Salt or saline solutions was another substitute . In experiments done on
frogs, it was found that it could keep frogs alive for some time, if whole
blood is replaced with a saline solution but it was little misleading, so,
Saline was developed as a plasma volume expander.
9. HISTORY
YEAR EVENTS
1868 WWII and Vietnam war ignited the search for blood substituents– Hemoglobin solutions
and Synthetic Oxygen carriers.
1871 Examined the use of animal plasma as substitute.
1883 Creation of Ringer’s solution by Sydney Ringer - a solution composed of sodium,
potassium, and calcium salts. scientists found that the heart could be kept beating by
applying the solution. This solution resembles Blood Serum.
• Led to findings that the reduction in blood pressure caused by a loss of blood
volume could be restored by using Ringer's solution.
• This product evolved into a human product when lactate was added.
Dr. Sydney Ringer
10. DESIGN
Ideal characteristics forArtificial Blood is:-
Safe to use
Compatible in the body- elimination of cross matching
Oxygen carrying capacity, equally or surpassing that of
biological blood
Pathogen and toxin free
Minimal side effects
Long shelf life
Survivability over a wider range of storage temperatures
Viscosity similar to Body blood
No immunosuppression
Cost efficient
11. BLOOD SUBSTITUENTS
Blood substituents can serve as :-
Plasma volume expander
Replicate the oxygen carrying function of natural blood
Plasma Expanders :- These are compounds, which are either entirely synthetic
or processed from natural proteins that serve as infusion solutions which expand
intravascular volume.
RBC Substituents :- these are oxygen carriers but, differ the way they carry.
They are:-
Modified Haemoglobins
Perflurocarbons
12. RED BLOOD CELL
SUBSTITUENTS
Main function is to carry oxygen, as does natural hemoglobin.
The use of oxygen-carrying blood substitutes is often called Oxygen therapeutics to
differentiate from true blood substitutes.
The initial goal of oxygen carrying blood substitutes is merely to mimic blood's oxygen
transport capacity.
13. There are two basic approaches to constructing an oxygen therapeutics:
The first is perfluorocarbons (PFC), chemical compounds which can carry and
release oxygen. The specific PFC usually used is either perfluorodecalin or
dodecafluoropentane emulsion (DDFPe).
The second approach is haemoglobin derived from humans, animals, or artificially
via recombinant technology, or via stem cell production of red blood cells in vitro
RED BLOOD CELL
SUBSTITUENTS
14. PFC blood substitutes
PFC are biologically inert
materials that can dissolve
about 50 times more oxygen
than blood plasma.
They are relatively inexpensive
to produce and can be made
devoid of any biological
materials.
Emulsion particles are 0.2
micron in diameter → Can
perfuse smallest capillaries,
where no RBC flow.
15. Not soluble in water, which means to get them to work
they must be combined with emulsions.
Now a day’s most of the PFBOCs are mixtures of
perfluorocarbons with emulsifying agent
PFC blood substitutes
16. They have the ability to carry much less oxygen than
haemoglobin based products.
This means that significantly more PFC must be used.
One product of this type has been approved for use by
FDA, but it has not been commercially successful because
the amount needed to provide a benefit is too high.
PFC blood substitutes
18. Advantages of Perfluorochemicals:-
Do not react with oxygen
Inexpensive
Allow easy transportation of the oxygen to the body
They allow increased solubility of oxygen in plasma
minimize the effects of factors like pH and temperature in blood circulation.
19. Disadvantages of Perflurochemicals:-
Often causes flu-like symptoms
Unable to remain mixed as aqueous solutions
Adecrease in blood platelet count.
PFC products cannot be used by the human body, and must be discarded.
PFCs absorb oxygen passively, patients must breathe at a linear rate to ensure
oxygenation of tissues.
The problem with Fluosal-DAwas that they dissolve less oxygen than pure liquids
20. REFERENCES
L. Kresie, Artificial blood: an update on current red cell and platelet substitutes,
Proc (Bayl Univ Med Cent). 2001 Apr; 14(2): 158–161; PMCID: PMC1291332
S. Sarkar, Artificial blood, Indian J Crit Care Med. 2008 Jul- Sep; 12(3):140-144;
PMCID: PMC2738310.
