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11-13-2009, 01:57 PM
¦Methods of blood transfusion:
1- Direct method ® Using special syrings blood is directly transfused from the donor to the recipient.
· It is not practical and not used nowadays .
2- Indirect method: ® The blood is collected from donors under strict aseptic conditions into sterilized bottles containing Na citrate in saline Dextrose.
¦Certain changes occur in stored blood :
· The blood bottles is stored in 4oC.
· It can be used immediately "Fresh blood" .
· The stored blood shows the following changes:
1- RBCs show hemolysis after 3 weeks . Moreover, If given after 3 weeks the RBCs survive only for short time .
2- Half of the Leucocytes are destroyed within the 1 st week .
3- Plateletes survive for only 1-2 days .
4- Prothrombin content loss ¼ of its amount after 1 week
5- Hemolysis of RBCs ® release its K into the serum ® ­ K content of the stored blood .
¦Blood components:
By utilizing double, triple or quadruple blood collecting sets a single unit of blood can be analyzed for its components.
1) Packed red blood cells.
2) Platelet rich plasma (Fresh frozen plasma).
The first collecting set containing whole blood is centrifuged at a speed which produces packed red cells and supernatant platelet rich plasma.
3) Platelet concentrate: the platelet rich plasma is centrifuged at high speed and the concentrate separated is a platelet concentrate.
¦Routes of transfusion :
1- I.V. Route; the commonest in use .
2- Bone marrow transfusion; the blood is transfused to sternum in adult and tibia of children It is rarely used nowadays.
3- Intra-arterial transfusion. It is seldom used nowadays.
¦ Blood grouping:
l Its done according to the presence of antigens responsible of incompatiblty.
l Tow types of blood groups are encountered:
1- ABO antigens.
2- Rh antigens: 85% of individuals have Rh antigen in blood but antibdies will be formed only in the blood of Rh negative individuals if received Rh positive blood.
¦ Indications of blood transfusion:
(a) Medical indications:
1- RBC'S: Haemolytic anaemia.
2 ­- ­WBCS: Leucopenia and agranulocytosis.
3- Platelets: Thrombocytopenia.
4- Proteins: Hypoproteinaemia.
5- Coagulation factors: Haemophilia.
(b) Surgical Indications:
1- Haemorrhge and shock.
2- Replace blood loss in operation "pre.,intra & post operative."
3- Severe infections causing toxaemia
4- To prime the machine in artificial kidney and heart lung machine.
¦ Precautions of blood transfusion:
× Blood transfusion from healthy person.
× Hb% > 90%.
× Haematocrit value not less than 40.
× Free from active infections or blood transmitted infection.
× Blood stored at 4C for not more than 21 days.
× Blood group should be the same and cross matching before transfusion should be done.
SOURCE: DR. AYMAN SALEM'S BOOK
Copyright: Vascular Society of Egypt (www.vsegypt.org (http://www.vsegypt.org/)) &Medical Educational web (www.meduweb.com (http://www.meduweb.com/))
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