Which intravenous fluid is classified as a hypertonic solution?

The classification of intravenous fluids as hypertonic, isotonic, or hypotonic is based on their osmolarity compared to the osmolarity of blood plasma. A hypertonic solution has a higher osmolarity than blood plasma, which means it draws water out of cells into the extracellular space.

In this case, 5% dextrose in normal saline can be considered a hypertonic solution. The combination of dextrose and sodium chloride increases the osmolarity significantly above that of normal blood plasma. While the dextrose initially provides isotonic properties, the presence of sodium chloride elevates the total osmolarity, thus drawing water out of cells, making it hypertonic in nature once metabolized.

This understanding helps clarify the effects this solution would have when administered. It is often utilized in clinical settings for patients who need not only hydration but also a source of calories, along with sodium supplementation.

In contrast, 0.9% sodium chloride is isotonic and does not exert the same osmotic effect, while 0.45% sodium chloride and Ringer's lactate are considered hypotonic and isotonic solutions, respectively, leading to different physiologic outcomes when administered to patients.