Hypotonic fluids, such as .25% saline or .45% saline, have been used since the 1950's as maintenance fluids in a hospital setting However, for several years, there has been increasing evidence that delivering these fluids can lead to hyponatremia.
Hypotonic fluids, such as .25% saline or .45% saline, have been used since the 1950’s as maintenance fluids in a hospital setting to reflect normal dietary sodium consumption. However, for several years, there has been increasing evidence that delivering these fluids can lead to hyponatremia. For example, a study1 published in 2011 in the journal Archive of Disease in Childhood reported that 60% of pediatric patients receiving hypotonic fluids went on to develop hyponatremia.
However, recent research suggests that this type of hospital-acquired hyponatremia is largely preventable. In a paper published in the journal Pediatric Nephrology in 2010, Michael L. Moritz, MD, Division of Nephrology, Department of Pediatrics, Children’s Hospital of Pittsburgh School of Medicine, described the administration of .9% sodium chloride (Na 154 mEq/L), an isotonic fluid, as a maintenance solution can be effective in managing appropriate patients.
Moritz notes that certain patients should still receive hypotonic fluids for maintenance, particularly patients with renal water losses or hypernatremia. However, in a review published in Renal and Urology News in March, Moritz and Juane Carlos Ayus, MD, of Renal Consultants of Houston in Texas, advocated for the use of isotonic fluids in patients, noting that previous studies had estimated that approximately 30% of patients receiving hypotonic fluids develop hyponatremia, while the incidence is only approximately 5% in patients receiving isotonic fluids.
Likewise, the authors noted that some pediatric and adult patients are dying from symptomatic hyponatremia due to inadequate therapy. For these patients, Mortiz recommends intermittent bolus therapy with 3% sodium chloride, 2 cc/kg with a maximum of 100 cc, to rapidly reverse central nervous system symptoms while preventing the possibility of overcorrection of hyponatremia.
“This simple change in practice would greatly reduce the incidence of hospital-acquired hyponatremia, virtually eliminate acute hospital-acquired encephalopathy, and translate into many saved lives in both children and adults,” the authors wrote.
1 Baker J, Armon K, Playfor S, et al. The use of hypotonic fluids in paediatric practice. Archive of Disease in Childhood. 2011;96:A60-A61.
2 Moritz ML, Ayus JC. New aspects in the pathogenesis, prevention, and treatment of hyponatremic encephalopathy in children. Pediatric Nephrology. 2011;25:1225-1238.