What does the term "isotonic" refer to?

The term "isotonic" refers to a solution that has an equal concentration of solutes or particles compared to another solution, typically a reference solution in the human body, such as blood plasma. This balance means that when isotonic fluids are introduced to the bloodstream, there is no net movement of water into or out of the cells, helping to maintain cell volume and homeostasis.

In practical terms, when an isotonic solution is administered, as in intravenous therapies, it ensures that the osmotic pressure is maintained, preventing cells from swelling (which would occur in a hypotonic solution) or shrinking (which would occur in a hypertonic solution). This property is crucial in various medical contexts, especially in fluid resuscitation and electrolyte balance.

The understanding of isotonic solutions is important in oral and maxillofacial surgery, as maintaining proper fluid balance is vital during and after surgical procedures.