Physiological Approach to Sodium Supplementation in Preterm Infants

Abstract

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 260/7 to 296/7 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.

Conflict of interest statement

None.

Thieme Medical Publishers 333 Seventh Avenue, New York, NY 10001, USA.

Figures

Fig. 1

(A) Estimated urine sodium concentration in infants 23 to 29 weeks of gestational age at postnatal ages of 2 to 8 weeks. Estimates based on the methodology outlined in text. (B) Estimated total urine sodium losses in infants 23 to 29 weeks of gestational age at postnatal ages of 2 to 8 weeks. Estimates based on the methodology outlined in text.

Fig. 2

Serum sodium versus urine sodium concentrations measured at 2 weeks (A), 4 weeks (B), 6 weeks (C), and 8 weeks (D) of postnatal age in infants born at 260/7 to 296/7 weeks’ gestation.

Fig. 3

Respiratory outcomes at 28 days of age for infants born at 260/7 to 29 6/7 weeks’ gestation in the 2014–2015 and 2016 cohorts. CPAP, continuous positive airway pressure; MV, mechanical ventilation; NC, nasal cannula; RA, room air.