How can blood transfusion help in :-?

Decreased oxygen lev. This is a clinical decision since patients with symptoms of hypoxemia(low oxygen) most likely will not improve until their oxygen carryin capacity (red blood cells and hemoglobin) are increased to support the normal function of the body. In cases of acute bleeding of 2 or more liters of blood, the patient most likely will need a transfusion (our body has 4-6 liters of blood or 10 pints).