Stored blood as compared to fresh blood has: September 2012

Ans. B i.e. High extracellular K+ Changes in whole blood during storage RBC As storage time increase, some RBC becomes spherical due to metabolic changes Associated increase in cell rigidity RBC transfused at maximum storage time -40-20% may be destoryed within 24 hours WBC Granulocytes lose phagocytic and bactericidal propeies within 4-6 hours Maintains their antigenic propeies Platelets Platelets becomes non-functional within 36-48 hours in blood stored at 4C Factor 5 and 8 Factors 5 and 8 are also called labile factors Decreases with storage of whole blood Following massive transfusion, coagulopathy due to dilutional thrombocytopaenia usually occurs before coagulopathy due to coagulation factor deficiency ATP ATP falls slowly to 75% at 28 days 2, 3-DPG In CPD-A blood, 2, 3-DPG decreases to 50% at 14 days and 5% at 28 days Low pH increases rate of 2, 3-DPG los Decrease in 2, 3-DPG is mainly due to reduction in Glycolysis Clinically, changes in p50 due to changes in 2, 3-DPG do not usually exceed 3.8mmHg Potassium level After the first 48 hours - Progressive loss of K+ from RBC into plasma - Plasma increase to about 12mmol/L at 7 days and 30mmol/L at 28 days Other changes Rise in RBC Fall in pH Loss of Ca2+ Formation of microaggregates Small amount of haemolysis