It totally depends on the age of the transfused blood. You are bound to observe varying degrees of pathophysiological changes following transfusion of very old blood.

Dear Jerricho

Infusion of very old blood can cause significant pathophysiological effects largely due to the ex-vivo changes/injuries to the blood cells that happen during storage. This is precisely the reason why there is a maximum limit to the storage time. Storage conditions (temperature, storage medium, contamination..) cause damage to the red cells. Red cell membrane undergoes changes (most reversible but some are not) resulting in impaired deformability, increased fragility and leakage of intracellular cations such potassium. Potassium levels in the storage medium goes up exponentially during storage. Hence, infusion of very old blood (in large quantities) can be potentially dangerous due to the effect of hyperkalaemia on the heart. Other products of metabolism also can cause pathophysiological effects. If red cells start to lyse in the storage medium, the cytoplasmic contents including free haemoglobin can cause deleterious effects. The other problem with transfusing very old blood is that the survival of the red cells post-infusion may be significantly reduced. Another serious problem with infusing very old blood is the risk of INFECTIONS. Some reports suggest that the cell fragments/microparticles released during storage may have immunolomodulatory effect.

Hope I have addressed your query.

Best wishes

Siva