Physiological Approach to Sodium Supplementation in Preterm Infants

Objective To implement and evaluate a clinical practice algorithmto identify preterm infants with sodium deficiency and guide sodium supplementation based on urine sodium concentrations. Study Design Urine sodium concentration was measured in infants born at 26(0/7) to 29(6/7) weeks' gestation at 2-week intervals. Sodium supplementation was based on the urine sodium algorithm. Growth and respiratory outcomes in this cohort were compared with a matched cohort cared for in our neonatal intensive care unit prior to algorithm implementation (2014-2015 cohort). Results Data were compared for 50 infants in the 2014-2015 cohort and 40 infants in the 2016 cohort. Urine sodium concentration met criteria for supplementation in 75% of the 2016 cohort infants within the first 4 weeks after birth. Average daily sodium intake was greater in the 2016 cohort compared with the 2014-2015 cohort (p < 0.05). Caloric, protein, and total fluid intakes were similar between cohorts. The change in weight Z-score between 2 and 8 weeks of age was significantly greater in the 2016 versus 2014-2015 cohort (0.32 +/- 0.05 vs. -0.01 +/- 0.08; p < 0.01). No impact on respiratory status at 28 days of age or 36 weeks of postmenstrual age was identified. Conclusion Institution of a clinical practice algorithm to instruct clinicians on sodium supplementation in preterm infants may improve growth outcomes.