[Perioperative fluid therapy in the pediatric patient. Recommendations].

Caloric and water requirements for basal metabolism in the hospitalized, not anesthetized children were calculated by Holliday and Segar in 1957 [1]. They developed an empirical equation estimating maintenance requirements: 100 mL/kg/day for the first 10 kg, 50 mL/kg /day for the second 10 kg and 20 ml/kg/day for the remaining kg with hypotonic solutions (saline 0.2%) containing 2-3 mEq/100 kcal/day and 3 mEq/100 kcal/day of sodium and potassium respectively (protocol 4/2/1). This requirements became a standard that made hypotonic solutions the maintenance solutions for most of the hospitalized children (also of anesthetized). However, in sick children, there are many non-osmotic stimuli that increase levels of antidiuretic hormone (ADH) that determine the loss of renal ability to remove free water and thus an increased risk of dilutional hyponatremia mainly if associated with perfusions with hypotonics fluids.