Hypertonic Solution Examples

Seawater has a high amount of salt particles compared to freshwater, making it a hypertonic solution. Freshwater fish can't live in seawater because the water would rush from their cells into the surrounding saltwater. They would soon die from dehydration. Saltwater fish, on the other hand, have adapted to their hypertonic solutions and rely on saltwater to regulate their cells. The same works for saltwater plants; while typical plants need water to flow into their cells, saltwater plants like mangroves and seaweed contain salt from their environments.

Have you ever tasted a sugary drink that was so sweet it made your mouth pucker? That's because there was more sugar in the drink than water, making it a hypertonic solution. Your lips puckered because the water from your mouth rushed into the drink, which dehydrated your mouth. Sugary drinks can also draw water from your intestinal cells, preventing you from absorbing nutrients. That's why sports drinks are less sugary than other drinks.

Healthy blood cells have the same amount of water as the fluid around them. But if you sweat a lot or lose more water than sodium in other ways, your extracellular fluid is now hypertonic and you are dehydrated. Osmosis occurs between the fluid and the red blood cells, which depletes your blood cells and prevents them from carrying oxygen. Hypertonic dehydration can be mild (thirst, dry mouth, tiredness) to severe (low blood pressure, poor kidney function, muscle cramping).

Hypertonic solutions are often administered in injections and hospital IV drips. They are given to patients with a buildup of fluid in their body issues (known as edema) to draw water away from the bloated tissues and back into the bloodstream. They are also used to replace electrolytes in the body of a sick and injured person who cannot consume food or liquids themselves. Here are a few IV solutions that are considered hypertonic.

Hypertonic saline describes any saline preparation with over 0.9% sodium chloride (which is known as normal saline). Doctors often prescribe 2% or 3% hypertonic saline to patients who need help diluting thick mucus. These patients include those with cystic fibrosis and severe bronchitis.

Hypertonic saline, particularly 7% or 23% hypertonic saline, is used to treat patients with traumatic brain injuries. It draws fluid out of cells to prevent cerebral edema. Typically, hypertonic saline over 3% is administered in a central line rather than in a standard IV drip.

Water with a large amount of dextrose can be an effective way to replace fluids and calories in an IV drip. This hypertonic solution is helpful for babies who are at risk for hypoglycemia (low blood sugar).

There can be some confusion over the terms hypertonic, hypotonic and isotonic. They all relate to the concept of tonicity, which is the concentration of a solution compared to another solution. The three types of tonicity are:

• hypertonic - more solutes than water (water flows from the cell into the solution; the cell shrinks)
• hypotonic - more water than solutes (water flows into the cell from the solution; the cell swells)
• isotonic - water levels between the cell and solution are stable (no water movement)

Most healthy body systems are isotonic, meaning that they work in equilibrium without much water movement. Another example of an isotonic solution is saline solution, various forms of which are used to replenish lost fluids in the body and clean contact lenses. Hypotonic solutions include solutions with a lot of water, including sports drinks, very diluted saltwater and tap water.

If you'd like to see a hypertonic solution in your own home, add a slice of carrot to a cup of saltwater. You'll find that it soon shrivels up as the water leaves the carrot cells for the hypertonic saltwater. Check out more examples of everyday solutions that you can find in your home, workplace or classroom. Or, if you're interested in more medical terms, take a look at these common medical abbreviations.