Which type of IV fluid is preferred for patients experiencing severe hyponatremia?

When addressing severe hyponatremia, hypertonic saline is commonly the preferred choice of intravenous fluid. This condition, characterized by a low concentration of sodium in the blood, can lead to serious neurological complications, and managing it requires careful correction of sodium levels.

Hypertonic saline (often a 3% solution) contains a higher concentration of sodium compared to normal blood plasma. When administered, it effectively increases the osmolality of the blood, which helps to shift fluid out of swollen cells into the bloodstream. This process is crucial, especially in acute cases, as it can aid in alleviating brain edema and reducing the risk of seizures and other complications associated with low sodium levels.

In contrast, isotonic saline, although useful in many situations, does not provide the necessary sodium concentration to effectively treat severe hyponatremia. Hypotonic saline, which would further dilute serum sodium levels, is also not suitable. Dextran is a volume-expanding agent but lacks any sodium content and would not address the underlying electrolyte imbalance. Hence, hypertonic saline emerges as the most effective option for treating severe hyponatremia, allowing for a controlled and monitored increase in serum sodium levels.