Which are common isotonic solutions used in IV therapy?

Isotonic solutions are crucial in IV therapy as they help to maintain fluid balance without causing shifts in body fluids between compartments. The key characteristic of isotonic solutions is that they have the same osmolarity as the blood plasma, which prevents hemolysis or dehydration of cells.

Normal saline, a solution consisting of 0.9% sodium chloride, is one of the most commonly used isotonic fluids. It is used for fluid resuscitation, to replenish lost fluids, and as a vehicle for medications. Lactated Ringer's solution is another widely used isotonic solution; it contains sodium, potassium, calcium, and lactate, and is often administered post-operatively or in cases of dehydration, as it closely resembles the electrolyte composition of human plasma.

Both of these solutions are effective in maintaining intravascular volume without causing fluid shifts that could disrupt cellular homeostasis. This is especially important in medical settings where fluid balance is critical, such as during surgery or in patients with acute illnesses.

In contrast, the other options include solutions that do not maintain isotonicity in various clinical contexts, as they either dilute body fluids or have excessive concentrations of solutes that can lead to fluid shifts. Understanding the properties of these solutions helps healthcare providers make