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Physical and Biochemical Effects of Blood Storage

You are here : Home/ Blood Bank Zone/ Preservation Storage Transportation of Blood / 3. Physical and Biochemical Effects of Blood Storage

3. Physical and Biochemical Effects of Storage

The conditions of storage will invariably produce changes in the physical and chemical properties of blood and blood components and in turn effect red cell recovery. The medical officers must be aware of these in order to consider the clinical efficacy of transfusion.
Abnormalities resulting from storage of blood are collectively known as storage lesions. These can be discussed as:
Storage lesions
1. Effect of collection on red cell recovery
2. Effect on red cell function and survival
3. Effect of anticoagulant used
4. Effect on pH
5. Effect of temperature
6. Effect on electrolytes & coagulation factors
7. Effect on cellular elements
1. Effect of collection on red cell recovery
The cell drawn at the start of donor bleeding are subjected to��n acidic and hypotonic anticoagulant solution which results in irreversible damage to some of the cells. These cells, in contrast to those drawn towards the end, of phlebotomy, deteriorate more rapidly on storage.
2. Effect on red cell funciton and survival
A) Storage effect on red cell metabolism : The red cell is dependent on anaerobic glycolytic pathway for the formation of ATP, which plays a central role in determining its viability and maintaining its shape. during preservation the metabolic cycle must continue in vitro for red cells to remain viable with adequate post transfusion survival and function.
B) Effect on 02 release and 2,3 Diphosphoglycerate (DPG): 2,3 DPG is known to profoundly lower the affinity of Hb for 02 at concentration found in red cells. Depletion of 2,3 DPG in stored blood temporarily adversely affects oxygen release by Hb.
C) Effect on survival In almost all cases cells that survive 24 hrs will remain viable and circulate for the remainder�of their expected life span.
Maximum allowable storage time, referred to as shelf life is defined by requirement of 70% recovery at 24 hrs i.e. at least 70% of the transfused red cells remain in the recipient�s circulation 24 hrs after transfusion.
3. Effect of anticoagulant-preservative
One of the most important factor influencing red cell recovery afterblood storage is the anticoagulant solution used.
1. Trisodium citrate Rapid deterioration, only 50% cells viable after 1 week.
2. Heparin- Rapidly deterioration. Added disadvantage of beinq progressively neutralized by plasma therefore, most unsuitable for storage.
3. ACD -Storage/viability for 28 days, 24 hrs survival 77%, DPG level better maintained at 1 week because of the favourable effect of higher p1-I.
4. CPD -Storage/viability for 28 days. 24 hrs survival 77%, DPG level better maintained at 1 week because of the favourable effect of higher pH.
5. CPDA-1/2 -Storage/viability 35 days - improved storae due to adenine which maintains high ATP level in the RBC.
4. Effect on pH
There is a gradual fall in pH during storage due to accumulation of lactic acid.
5. Effect of temperature
Optimum storage temperature for whole blood and red cells is between 2�-6� with occasional elevation to 10�C (e.g. during transportation) being acceptable.
Delaying refrigeration increases the loss of 2,3 DPG over this period. Platelets and granulocyte retain better function when stored at room temperature. Labile coagulation factors in plasma are best maintained at temperature of -20�C or lower.
Refrigeration and freezing additionally minimize proliferation of bacteria that might have entered the unit during venepuncture.
Biochemical changes of stored CPD and CPDA - 1 blood

	CPD				CPDA-1
	Days of storage				Days of storage
	0	7	14	21	0	35
% of viable cells (24 hr.post transfusion)	100	98	85	80	100	79
Plasma pH (measured at 37�C)	7.20	7.00	6.89	6.84	7.6	6.98
ATP (%initial value)	100	96	83	86	100.0	56.0
2,3 DPG (% initial value)	100	99	80	44	100.0	<10.0
p50	23.5	23	20	17
Plasma Na meqll	168	166	163	156	169.0	155.0
Plasma K meq/l	4.2	11.9	17.2	21.0	4.2	27.3

6. Effect on electrolytes & coagulation factors
A. Electrolytes The only important electrolyte change in stored blood is that of K. During blood storage there is a slow but constant leakage of K+ from cells into the surrounding plasma. In severe kidney diesease even small amount of K+ fluctuations can be dangerous and relatively fresh or washed red cells are indicated. Due to a higher K+ content of stored blood, blood < 5 days old is recommended for neonatal exchange and top-up transfusion.
B. Coagulation factors : Labile coagulation factors, Factors V and�VIll lose their activity by 50% within 48-72 hrs of storage.
7. Effect on cellular elements
White cells lose their phagocytic and bactericidal property within 4-6 hrs of collection and become non-functional after 24 hrs of storage. It is important to remember that they do not lose their antigenic property and are capable of sensitizin the recipient to produce non-haernolytic febrile transfusion reactions.
Few lymphocytes may remain viable even after 3 weeks of storage.
Platelets lose their haemostatic function within 48 hrs in whole blood stored at 4�C.

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