Final answer:
Normal Saline is used in blood transfusions because it is isotonic with blood, prevents hemolysis of red blood cells, and maintains the balance of fluids and electrolytes, which is crucial in emergency situations when immediate blood type matching is not possible.
Step-by-step explanation:
Normal Saline (NS) is the solution of choice when preparing to administer a blood transfusion for several reasons. First, NS is isotonic with blood, meaning it has the same osmolarity, which helps to prevent the hemolysis of red blood cells that could otherwise occur if a solution with a different osmolarity were used. This is crucial as hemolysis can lead to severe complications for the patient. Additionally, NS contains fluids and electrolytes in proportions equivalent to those of normal blood plasma, supporting the patient's circulatory system during the transfusion process.
This is especially important when the patient requires an immediate transfusion, and there is no time to determine their blood type, making the use of type O blood or a blood substitute necessary. Also, in emergency settings, such as at a scene of an accident or a battlefield, where type O blood may not be available, NS can be used to stabilize patients by replacing lost blood volume temporarily.