Stored blood is one of the commonest transfused volume replacements. Blood is stored in the cold part of refrigerator at 4°C (never in the freezer). Since blood from donors it taken long before it has to be given to a patient, it is stored in the meantime in refrigerator to preserve it from getting spoiled.
It can be stored for 21 days if acid citrate dextrose is used.
It can be stored for 35 days if the preservative anticoagulant solution used is CDPA.
- C for Citrate as anticoagulant.
- D for Dextrose as energy source for red cells.
- P for Phosphate as buffer.
- A for Adenine to increase the red cell survival.
CDPA is most commonly used anticoagulant in India.
It can be stored for 42 days if anticoagulant preservative solution used is ADSOL (Adenine, glucose, mannitol and sodium chloride) or NUTRICE (Adenine, glucose, citrate, phosphate and NaCl).
Changes in Stored Blood
- pH: It decreases to about 6.98 at 35th day of storage.
- Hemoglobin concentration: Decreases (70% at 35th day) i.e., 12 g%
- Hematocrit : Decreases (40% at 35th day)
- Potassium : It increases in the stored blood as the potassium from RBCs enter the plasma.
- 2,3 DPG level: Decreases (< 1 microm/mI at 35th day; normal is 13.2 microm/ml)
- Platelets : – Decreases (only 5% at 48 hours)
- Clotting factors : Factor V only 15% at 21 days, Factor VIII only 50% at 21 days. Rest all factors are comparatively stable in stored blood.