Physiological Approach to Sodium Supplementation in Preterm Infants.

Objective: To implement and evaluate a clinical practice algorithm to 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 to 29 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 ( < 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;  < 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.