BLOOD FOR BLOOD

5. BLOOD TRANSFUSION

The varieties of hemorrhages have been dealt with in detail in chapter on Shock(Chap3).
We need to discuss here some clinical methods for assessing the
amount of blood loss so as to start treatment.

To estimate blood loss in the ward or emergency room:

* Swabs can be counted and weighed to estimate blood loss
* The clots can also be weighed to calculate blood lost
* In closed wounds, a moderate swelling in the leg may indicate
a loss of 1000-1500 cc of blood
* A similar swelling in the thigh (fracture femur) may
indicate a loss of 1000-2000cc
* Fracture pelvis may indicate a loss of >2000cc

Blood loss of <20% need not be replaced with whole blood.
-Immediate circulating fluid needs are provided by the transfer of fluid from the extra-vascular compartments.
-Protein lost in the blood is replaced by the body protiens in days
-RBC are replaced in weeks.

-Blood loss of 20-25% can be replaced by saline,
-loss of 30-35% may require replacement with plasma substitutes.
-When loss of 50% or more occurs replacement with whole stored blood is
required.

BLOOD is required in all cases of acute blood loss:

* Trauma + haemorrhage-(fracture)
* Intra-operative
* Post-operative
* In cases of deep burns
* In cases of bleeding disorders

5.1 HOMOLOGUS BLOOD

Stored blood is obtained from donors and kept in bags of 300cc.
Each donor needs to be carefully screened to limit the risk of
transmission of disease to the recipient.

5.2 AUTOLOGOUS BLOOD

Patient can donate his own blood within 5 weeks prior to the
surgery.
This blood can then be used at the time of surgery.
Blood lost during surgery can also be collected at that time
Washed, filtered and re-infused.

5.3 Blood Grouping and Cross Matching
Transfusion of blood require arrangements with the blood
bank
-to group patient's blood and
-cross match sample of blood
with sample of the same group in the blood bank.

-For this purpose a sample of blood has to be obtained from the
patient.
-All red cells contain agglutinogens (A and B).
-The serum contains Agglutinins (Anti A and Anti B).

5.4 Rh Factors
This is an antigen found in Red Cells and human red cells can be
either Rh+ or-.
Antibodies in the serum develop if Rh positive cells are
injected in Rh negative.
At the 1st repeat transfusion no problem may arise but subsequently
transfusion may produce Haemolysis.
Approximately 85% of the population is Rh positive.

Before transfusion the red cells of the donor (stored blood) are
matched against the serum of the recipient (the patient)
Any questions be sent to drmmkapur@gmail.com