Blood products and plasma substitutes –

Blood is a connective tissue which makes 7-9% part of total body weight of adult human. The
total volume of blood is 4.5 to 5.5 liter in an adult. The functions of blood include – maintenance
of pH (7.35 – 7.45), transportation of gases (O2 and CO2), Transportation of different
metabolites, nutritious substances, hormones, drugs and nitrogenous waste products of body like
urea, ammonia etc., regulation of immune defence and body temperature. Blood is a natural
buffer that regulates acid- base balance in body.

Different blood products –The various types of products that are obtain from blood and useful
in different blood related threats are known as blood products-

1. Whole human blood – Whole human blood is red coloured opaque concentrated solution which
include total blood composition with extra anticoagulants in it. On standing state of 24 to 48
hours it’s corpuscles are readily settled in bottom part and clear supernatant layer is seen.
Collection – Always blood should be collected from healthy human with no infectious disease
state under rigid aseptic environment. The blood is collected from median cubital vein in front
of elbow in a sterile container. Blood is collected with adequate mixing of the anticoagulants in
the container (plastic bag or glass bottle). Not more than 420 ml is collected in one attendance.
Storage – After withdrawal of the blood from healthy human, it should be cooled immediately at
4℃ to 6℃ and regularly maintain this temperature throughout it’s shelf life of 21 days.
Anticoagulants- For prevention of fibrin clots anticoagulants are added in blood. The
anticoagulants generally added are citrates, heparin and Disodium edentate. Acid citrate dextrose
(ACD) is used as blood anticoagulant solution. The dextrose delays haemolysis of erythrocytes
in vitro and prolongs their life after transfusion and citrate prevents clotting by binding with
calcium ions as unionized calcium citrate. Heparin is expensive, it is used when large volumes of
blood is transfused to one patient, where high amount of citrate is harmful, for example in
cardiac surgery.
Testing- At the time the blood is taken, two small additional amounts are collected one for
testing of compatibility of blood and other one for testing of Rh grouping and blood groups.
Use – The volume of blood can be reduced to dangerously low level by haemorrhage, burn,
shock, diarrhea and vomiting. Whole human blood is transfused to replace total blood or part of
blood either cellular or plasma and also useful in total restore of blood volume in acute
haemorrhagic condition in stroke and trauma patient.

2. Concentrated human red blood corpuscles - It is prepared from whole human blood which is
not more than 14 days old according pharmacopoeial regulations. The upper supernatant fluid is
siphoned off and cellular layer of whole human blood after centrifugation is collected to prepare
concentrated human red blood corpuscles.
Storage – Storage temperature of concentrated human red blood corpuscles is 4℃ to 6℃ as it
prepared from whole human blood. It should be used within 12 hours of preparation to avoid risk
of bacterial contamination.
 Use - Concentrated human red blood corpuscles are transfused to treat various types of anaemia.

3. Plasma – Plasma is also prepared from whole human blood that is collected as the supernatant
layer after centrifugation ( as mentioned in concentrated RBCs).
Storage – Storage temperature for Plasma is also 4℃ to 6℃ but it should be used immediately
after preparation due to its unstability in liquid state.
Use – In haemorrhage and shock, plasma is used as replacing agent of blood volume as it has
similar osmotic properties and nutritional values of whole human blood. Whole blood is ideal for
this purpose but it is not readily available so plasma can be used as substitute of whole human
blood in haemorrhagic or shock patients.

4. Dried human plasma - As whole human blood requires refrigerated storage and need to be used
within three weeks, dried human plasma is prepared by plasma with the help of freeze drying
after sterility testing. Dried plasma is usually prepared from time expired citrated blood. The
supernatant fluid is separated and batches of 10 bottles are pooled, correct ratio of blood groups
is chosen to neutralize the agglutinins. The pools are kept at 4 to 6 ℃. After sterility testing
they are subjected to freeze drying. It is a light deep cream sterile powder which is
reconstituted with the help of water for injection at room temperature. It can be given to patients
of any blood group.
Dried human serum is prepared in same way as dried plasma except that the blood is collected in
dry bottles and allowed to clot, supernatant serum is separated after the clot formation.
Storage - Dried human plasma should be stored at room temperature but temperature should not
exceed 45℃. If properly stored dried plasma can be kept for five years. Dried plasma kept below
20℃ and protected from light, moisture and oxygen remain usable. It is reconstituted in
water for injections, sodium chloride injections or 2.5 percent dextrose. After
reconstitution it should be used immediately.
Use – It is used as restoration agent of blood volume in hemorrhage, severe burns and shock
condition. Reconstituted plasma is a satisfactory alternative to whole blood if there is no loss of
red blood cells. Due to its long shelf life it can be kept in reserved stock.

5. Plasma Protein Fraction – The only official liquid blood product is human plasma protein
fraction. About 60 percent of plasma protein is albumin and it plays major role in maintaining
high osmotic pressure necessary to retain fluid in blood vessels. It is a fraction of plasma in
which selected proportion of albumin and globulin proteins remains protein concentration
45gm/lit. Fractionation process involves the reduction in solubilities of proteins in plasma by
use of organic solvents like ether and ethanol at low temperatures. It is an isotonic solution of
neutral pH and additional microbial and stabilizing agent (sodium caprylate or acetyl tryptophan
added to allow the preparation to be heated for several hours at a low temperature without
denaturation of proteins).
Storage - Plasma Protein Fraction should be stored at 2℃- 10℃ for 5 years.
 Use –Plasma protein fraction used as source of protein and replacing agent in non- haemorrhagic
shock. Human Albumin – It is obtained from pooled human plasma. Heat treated preparation of
human albumin can be used in acute hypoproteinaemia, acute liver failure and dialysis.

Plasma Substitutes –

Due to limited supply of blood, limitation in the quantity of human blood products and risk of
transmission of serum hepatitis lead to find the substitutes from non-human origin. Plasma
substitutes or plasma expanders have relatively high molecular weight substances and capable to
increase plasma volume by increasing osmotic pressure. These agents should be iso-osmotic with
plasma and pharmacodynamically inert and free from toxicity. The uses of plasma substitutes are
commonly as in hypovolemic shock, prevention of thrombosis and also useful as isotonic
solution. The following agents are useful for substitute of plasma –

1. Gum saline- It is a synonym of sodium chloride and acacia injection. It was used in first world
war, it is 6 % Acacia in 0.9 % NaCl solution.
2. Polyvinyl pyrrolidone-In Second World War Germans introduced this synthetic colloid for
treatment of shock. It is a synthetic polymer of average molecular weight 40,000. It is used as
3.5% solution.
3. Dextran- It is the most satisfactory and common example of plasma substitutes with highest use.
Dextran is highly branched polysaccharide that is obtained from fermentation of sucrose using a
strain of leuconostoc mesenteroids. It means dextran is a product of bacterial origin from sucrose
medium. In sugar industry it occurs as slime that clogs pipes and filters. The organism secretes
an enzymethat converts sucrose to dextran. Production of dextran is by process of fermentation
through cultures.This most commonly used plasma expander is available mainly in two forms –
Dextran 40 and Dextran 70.
4. Dextran 40 – Dextran 40 is a polymer of glucose that have average molecular weight 40,000. In
this polymer the monomeric units of glucose are linked together by 1,6-glycosidic linkage.
Dextran 40 is a white, amorphous powder without taste and odour. Also it is freely soluble in
water. It acts more rapidly than dextrose 70. It is given by intravenous infusion of 10%
concentration of normal saline.
Storage – Dextran 40 can be stored at room temperature for 5 years.
5. Dextran 70 – It is the most commonly used preparation of Dextran that expands plasma volume
for nearly 24 hrs. Dextran 70 is a polymer of glucose that have average molecular weight 70,000.
6. Degraded gelatin polymer – It is a synthetic polymer of molecular weight 30,000 that is obtained
from bone and hydrolysed under controlled conditions. It expands plasma volume upto 12 hrs.
7. Hydroxyethyl Starch – It is a complex mixture of amylopectin which has been treated with
ethylene chlorohydrins. It improves hemodynamic status for 24 hours.
8. Absorbable haemostats- These materials are used to control and arrest bleeding when it cannot
be controlled by more conventional means. They are gradually absorbed by the tissues and can
be left in body during surgery. The examples include human fibrin foam, gelatin sponge,
oxidized cellulose and calcium alginate. Human fibrin foam is sponge like mass of human fibrin.
It is prepared by whipping the fibrinogen froth and adding thrombin to it. It is poured into trays
and freeze dried and sterilized. A piece of fibrin foam is dipped into thrombin solution and
applied to bleeding area. Absorbable gelatin sponge is prepared by adding small percentage of
formaldehyde to warm solution of gelatin and whisked into a foam and freeze dried. The porous
product is cut into pieces and sterilized by dry heat. It is marketed as papery white pieces that are
extremely light and spongy. It absorbs many times its own weight of blood. Oxidised cellulose is
an absorbable haemostatic material where cellulose is converted into polyanhydro glucuronic
acid by oxidation with nitrogen dioxide. On contact with blood it turns dark and swell to
gelatinous coagulum. Calcium alginate is derived from alginic acid, a colloidal substance
obtained from seaweeds Laminaria digitata. Alginic acid is a polyuronide built up from d-
manuronic acid units. Its carboxyl groups react with metal ions to form alginate. Calcium
alginate dressing have marked haemostatic effect that is due to mechanical pressure.It is used to
arrest external bleeding from surgical incisions, tooth sockets. A transparent protective film can
be made in situ over a burn, incision or wound by applying a solution of sodium alginate and
then spraying with calcium chloride solution. The film is impervious to water but permeable to
water vapour.