Hypotonic versus isotonic maintenance fluids in critically ill pediatric patients: a randomized controlled trial

Abstract

Introduction: Hypotonic fluids have been associated with the development of iatrogenic hyponatremia.

Objectives: To assess variations in serum sodium (sNa) following the intravenous administration of isotonic maintenance fluids (0.9% NaCl/5% dextrose) compared to hypotonic maintenance fluids (0.45% NaCl/5% dextrose).

Material and methods: Randomized, controlled, double-blind clinical trial. Pediatric patients with an expected length of stay in the intensive care unit of more than 24 hours were enrolled, with normal serum Na, and IV fluids >80% of total maintenance fluids. Serum Na level was measured before administering maintenance fluids and when reducing the administration to <80% of total fluids.

Results: The study included 63 patients who were randomly assigned to receive hypotonic (n= 32) or isotonic (n= 31) maintenance fluids. Baseline characteristics were similar in both groups. There were no differences in terms of volume of fluid administered (hypotonic group: 865 ± 853 mL; isotonic group: 778 ± 649 mL; p= 0.654) or infusion duration (hypotonic group: 24 ± 10.8 hours; isotonic group: 27.6 ± 12.8 hours; p= 0.231). A difference was found in the serum Na following the administration of maintenance fluids (hypotonic group: 137.8 ± 4.3 mmol/L; isotonic group: 140.0 ± 4.1 mmol/L, p= 0.04). None of these two maintenance fluids increased the risk of hyponatremia (Na 145 mmol/L).

Conclusions: Neither hypotonic nor isotonic maintenance fluids increased the risk of developing iatrogenic hyponatremia with the 24 hour infusion.

Trial registration: ClinicalTrials.gov NCT01301274.