What do hypertonic saline solutions generally do to body osmolarity?

Hypertonic saline solutions are characterized by having a higher concentration of solutes compared to the body's own fluids. When hypertonic saline is administered, it introduces additional solutes into the extracellular space. This increase in solute concentration creates a gradient that draws water out of the cells and into the extracellular fluid in an attempt to equilibrate osmolarity across the membranes.

As a result, the overall osmolarity of the body fluids increases. This effect can be critical in certain medical situations, such as managing conditions like hyponatremia, where raising serum sodium levels is necessary. The administration of hypertonic saline can lead to a significant alteration in fluid distribution within the body, promoting fluid shifts that elevate osmolarity.

In summary, hypertonic saline solutions increase body osmolarity by contributing to a higher concentration of solutes in the extracellular compartment, which affects the distribution of water and solutes within the body.