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Rules of blood transfusion
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Rules of blood transfusion

The blood should have the same group and same rhesus. Before, people with I(O) blood group are thought to be universal donors. Their blood was used to transfuse to the recipients of other groups. Now these blood transfusions are not allowed. Why? Erythrocytes of I group do not have antigens A and B and in fact packed red cells of I group can be transfused to the recipients of other group. But plasma of I blood group includes agglutinins ? and ?, that’s why it can cause agglutination in blood, which includes agglutinogens A and B (blood with II, III and IV group). This plasma can be injected to the recipients in limited quantities, so transfused agglutinins will be dissolved and agglutination will not occur.

Blood should not be injected more than 500 ml of blood at once.

Blood should not be transfused from the same donor more than once.

Indication of Blood Transfusion:

 Decreased blood volume (>20% is lost):e.g. in haemorrhage.

Decreased R. B. Cs.in anemia when Hb % is below 40%.

Decreased W. B. Cs. (leucopenia).

Decreased blood platelets (thrombocytopenic purpura).

Decreased coagulation factors VIII, IX, and XI in haemophilia.

In erythroblastosis fetalis: exchange transfusion to replace the infant’s blood with Rh-ve group O blood.

Dangers of blood transfusion:

Dangers of Incompatibility:

agglutination (clamping) of the donor”s R.B.Cs. This:

a) blocks the capillaries and causes severe pain;

b) Blocks the blood vessels, e.g. of the heart causing myocardial infarction or thr brain causing paralysis.

 hemolysis of the donor’s R.B.Cs. leads to jaundice due to excess formation of bilirubin;

 hypotension: fall of arterial blood pressure due to V.D. caused by histamine released from hemolysed R.B.Cs;

decreased urine volume (oliguria) or even anuria and death may occur from renal failure, caused by:

a) hypotension;

b) precipitation of Hb (acid hematin) and blocking of renal tubules causing anuria;

c) fatal hyperkalaemia may result from hemolyssis of R.B.Cs. and failure of K + excretion due to renal failure;

d) fatal hypokalaemia, may occur during recovery, since K filtered from the glomeruli is not reabsorbed by damaged renal tubules.

Transmsssion of Diseases:

As syplilis, malaria, viral hepatitis or AIDS.

Allergic reactions:

Rigors and fever may occur due to presence of pyrogens.

Transmsssion of excessive amount of blood:

This may cause an overload and leads to heart failure.

Tetany:

Increased neuromuscular excitability due to decreased calcium level in plasma. It may occur due to excessive amount of citrate in the transfused blood.



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