What would happen if someone was given saline that was not isotonic
The correct answer and explanation is:
If someone is given saline that is not isotonic, the balance of water and electrolytes between their blood and body cells can be disrupted, potentially causing cellular swelling or shrinking, depending on whether the solution is hypotonic or hypertonic.
Correct Answer:
If non-isotonic saline is administered, it can cause serious physiological disturbances. Hypotonic saline can lead to cell swelling and possibly lysis, while hypertonic saline can cause cell shrinkage and dehydration.
300-Word Explanation:
Isotonic saline, typically 0.9% sodium chloride, has the same osmolarity (~308 mOsm/L) as human blood plasma. This means that when it is administered intravenously, it does not cause a net movement of water into or out of cells. It maintains fluid balance and is commonly used for hydration or during surgery.
However, non-isotonic saline solutions can be hypotonic (lower concentration of solutes than blood) or hypertonic (higher concentration of solutes).
- Hypotonic Saline (e.g., 0.45% NaCl):
- Has a lower osmolarity than blood plasma.
- Causes water to move into cells by osmosis.
- This can lead to cellular swelling, and in severe cases, cell lysis (bursting).
- In the brain, this can be particularly dangerous, potentially leading to cerebral edema and increased intracranial pressure, which may result in confusion, seizures, or coma.
- Hypertonic Saline (e.g., 3% NaCl):
- Has a higher osmolarity than plasma.
- Causes water to move out of cells into the bloodstream.
- This leads to cellular shrinkage, which can impair cellular function.
- In the brain, it can be used carefully to reduce cerebral edema, but if misused, it can cause neuronal dehydration, confusion, or demyelination (osmotic demyelination syndrome).
In summary, giving a patient non-isotonic saline without proper indication or monitoring can be dangerous. The choice of solution must be guided by the patient’s condition, electrolyte levels, and volume status to avoid serious complications.