Isotonic Versus Hypotonic Fluid for Maintenance IV Therapy

Hyponatremia associated with administration of hypotonic intravenous (IV) fluids may have serious complications. It has recently been suggested that isotonic saline may be a more appropriate choice of maintenance IV fluid. This pilot and feasibility study aims to compare isotonic saline to 0.45% saline in hospitalized children requiring parenteral fluid support in order to: Aim 1: To determine the feasibility of conducting a double-blind, randomized controlled trial comparing these solutions. Aim 2a: To compare the rate of change in serum Na (mmol/L/hr) and the incidence of hyponatremia (Na \<136 mmol/L) between patients receiving isotonic and hypotonic intravenous fluids at at least 50% of the traditional maintenance rate for an interval of at least 8 hours. Aim 2b: To compare the incidence of adverse events between the two IV fluid treatment groups.