Medical Applications of Isotonic Solutions
1. Intravenous Fluids
- Intravenous (IV) fluids are used to rehydrate patients, deliver medications, or maintain blood pressure.
- The most common isotonic IV fluid is normal saline, which contains 0.9% sodium chloride (NaCl).
Normal saline is isotonic to human blood, making it safe for direct infusion into the bloodstream.
Why Isotonicity Is Critical
- Prevents cell damage: Ensures red blood cells and other cells maintain their normal shape and function.
- Maintains blood volume: Helps stabilize blood pressure and circulation during medical procedures or dehydration.
- A common mistake is assuming that any sterile solution can be used for IV fluids.
- Only isotonic solutions like normal saline are safe for direct infusion into the bloodstream.
2. Organ Transplantation
- During organ transplantation, organs must be preserved outside the body.
- Isotonic solutions are used to bathe the organs, preventing cellular damage.
How It Works
- Prevents swelling or shrinking: Maintains the organ's cellular integrity.
- Provides cooling: Isotonic solutions can be cooled to slow metabolic processes, extending the organ's viability.
A donor liver may be bathed in an isotonic solution containing nutrients and then packed in isotonic saline slush to keep it cool during transport.
