IV fluid induced hyponatremia

Hospitalized patients are frequently prescribed parenteral fluids and in most instances these are hypotonic (e.g. 0.18 % NaCl in 5 % dextrose). Controversy surrounds the routine use of hypotonic parenteral fluids because they can cause hyponatremia (reduced plasma sodium concentration), which if sufficiently severe can lead to permanent brain damage or even death. 

The controversy is the subject of a recent review in which the authors argue that routine use of hypotonic fluids should now be abandoned in favor of isotonic fluid (0.9 % NaCl) for most patients. Among the topics discussed is the pathogenesis of hyponatremia, including a description of the mechanism by which hypotonic fluid can cause hyponatremia. 

There follows a review of the extensive clinical evidence linking hyponatremic-induced brain injury and deaths with administration of hypotonic fluids, as well as evidence of the safety and effectiveness of 0.9 % NaCl (there is not a single report of hyponatremic-induced brain damage resulting from administration of 0.9% saline).