Hypotonic versus isotonic intravenous maintenance fluids in critically ill pediatric patients: a randomized clinical 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 <135 mmol/L) or hypernatremia (Na >145 mmol/L). Conclusions. Neither hypotonic nor isotonic maintenance fluids increased the risk of developing iatrogenic hyponatremia with the 24 hour infusion. © 2013 Sociedad Argentina de Pediatría.