Why is normal saline (NS) the solution of choice for administering a blood transfusion?

Normal saline (NS) is the solution of choice for administering a blood transfusion primarily because it is isotonic, meaning it has a similar osmotic pressure to that of the body's cells and plasma. This characteristic helps maintain fluid balance and prevents the risk of hemolysis, which can occur if a hypotonic solution is used. When blood products are transfused, it's essential to use a solution that does not disrupt the red blood cells’ integrity and maintains the stability of the blood components.

Isotonic solutions like normal saline ensure that fluid shifts do not occur inappropriately between the bloodstream and the cells, which could lead to complications. Using an isotonic solution facilitates the infusion of blood products without causing adverse reactions related to osmolarity, such as swelling or burst red blood cells.

While normal saline does not prevent allergic reactions or enhance blood clotting, and although other fluids may be used under certain circumstances, its compatibility with blood products during transfusions is primarily due to its isotonic nature. This ensures that the administered blood products function as intended without introducing additional risks associated with the fluid used.