Physiological approach to sodium supplementation in preterm infants
Gregory Sokol, MD
BACKGROUND: Postnatal growth failure is a significant morbidity affecting up to 50% of very low birth weight (<1500 gram) infants. The need for adequate sodium intake to optimize growth is apparent from studies in animals and humans. Because premature infants have high sodium requirements, unrecognized total body sodium depletion likely contributes to postnatal growth failure
GAP: Serum sodium concentrations are used currently to guide the initiation of sodium supplementation, however they may remain normal despite a state of sodium deficiency. An algorithm utilizing urine sodium concentration (more reflective of total body sodium homeostasis) may be a better guide to maintain sodium adequacy.
HYPOTHESIS: Compared to current treatment practices, use of an algorithm based on urinary sodium concentrations to guide sodium supplementation will result in improved growth (weight, length and head circumference) from birth to hospital discharge in preterm infants.
METHODS: A pragmatic randomized trial with a sample size of 41 patients in each arm (use of urine sodium algorithm vs. conventional management). Infants randomized to the algorithm will have a spot urine sodium concentration determined every 2 weeks with sodium supplementation provided according to the algorithm.
IMPACT: Reducing postnatal sodium deficiency in very low birth weight infants will enhance growth and promote further study on the impact of this algorithm on neurodevelopmental outcome.