Improving intravenous fluid therapy in children with gastroenteritis

Gastroenteritis is one of the most common medical conditions seen by pediatricians. The standard approach to intravenous fluid therapy for these children has been to administer a 0.9% sodium chloride (NaCl) bolus followed by a hypotonic solution ranging from 0.2-0.45% NaCl to replace the remaining deficit plus maintenance. We have questioned the safety of this approach as there have been reports of death or permanent neurologic impairment from hyponatremic encephalopathy. Hanna and Saberi (Pediatr Nephrol. doi: 10.1007/s00467-009-1428-y ) found the incidence of hospital-acquired hyponatremia (sodium < 135 mEq/L) to be 18.5% for patients presenting with isonatremic dehydration from gastroenteritis. This confirms that the current approach of using hypotonic fluids results in a high incidence of hyponatremia. Hypotonic fluids are not appropriate for rehydration in patients with gastroenteritis as it is a state of arginine vasopressin (AVP) excess due to both hemodynamic stimuli from volume depletion and non-hemodynamic stimuli such as nausea and vomiting. Free water will be retained until the volume deficit is corrected and the hemodynamic stimulus for AVP production abates. A safer and more effective approach is the administration of 0.9% NaCl in a continuous infusion following bolus therapy. 0.9% NaCl not only serves as prophylaxis against hyponatremia, but it is superior to hypotonic fluids as an extracellular volume expander and corrects the volume deficit more rapidly.