Jeffrey L Segar1,2, Connie C Grobe3, Justin L Grobe4,5,6,7,8. 1. Division of Neonatology, Department of Pediatrics, Medical College of Wisconsin, 999 North 92nd St, Suite C410, Milwaukee, WI, 53226, USA. jsegar@mcw.edu. 2. Department of Physiology, Medical College of Wisconsin, Milwaukee, WI, USA. jsegar@mcw.edu. 3. Division of Neonatology, Department of Pediatrics, Medical College of Wisconsin, 999 North 92nd St, Suite C410, Milwaukee, WI, 53226, USA. 4. Department of Physiology, Medical College of Wisconsin, Milwaukee, WI, USA. 5. Comprehensive Rodent Metabolic Phenotyping Core, Medical College of Wisconsin, Milwaukee, WI, USA. 6. Dept of Biomedical Engineering, Medical College of Wisconsin, Milwaukee, WI, USA. 7. Cardiovascular Center, Medical College of Wisconsin, Milwaukee, WI, USA. 8. Neuroscience Research Center, Medical College of Wisconsin, Milwaukee, WI, USA.
Abstract
BACKGROUND: Sodium depletion results in impaired somatic growth. The sodium requirements of extremely preterm (periviable) infants early in life are not known. We therefore investigated sodium homeostasis in this population over the first 10 weeks following birth. METHODS: This was a longitudinal, observational study of sodium intake and urine sodium excretion in a convenience cohort of 23 infants born at 22 0/7-23 6/7-week gestation. RESULTS: Sodium intake ranged from 5.2 ± 0.4 to a maximum of 7.9 ± 0.5 mEq/kg/day at 2 and 8 weeks of postnatal age, respectively, while urinary sodium loss was 7.7 ± 1.0 mEq/kg/day and 6.9 ± 0.7 mEq/kg/day at these time points. Sodium balance (sodium intake - urine sodium output) was first positive at 6 weeks of age, though a positive sodium balance exceeding 1.4 mEq/kg/day (i.e., a balance associated with weight gain of 30 g/day) was not observed until 10 weeks. CONCLUSIONS: Infants born at 22-23-week gestational age have a prolonged period of high urinary losses of sodium and negative sodium balance. Sodium intakes greater than those currently recommended by the American Academy of Pediatrics are needed to achieve a significant positive sodium balance in this population.
BACKGROUND: Sodium depletion results in impaired somatic growth. The sodium requirements of extremely preterm (periviable) infants early in life are not known. We therefore investigated sodium homeostasis in this population over the first 10 weeks following birth. METHODS: This was a longitudinal, observational study of sodium intake and urine sodium excretion in a convenience cohort of 23 infants born at 22 0/7-23 6/7-week gestation. RESULTS: Sodium intake ranged from 5.2 ± 0.4 to a maximum of 7.9 ± 0.5 mEq/kg/day at 2 and 8 weeks of postnatal age, respectively, while urinary sodium loss was 7.7 ± 1.0 mEq/kg/day and 6.9 ± 0.7 mEq/kg/day at these time points. Sodium balance (sodium intake - urine sodium output) was first positive at 6 weeks of age, though a positive sodium balance exceeding 1.4 mEq/kg/day (i.e., a balance associated with weight gain of 30 g/day) was not observed until 10 weeks. CONCLUSIONS: Infants born at 22-23-week gestational age have a prolonged period of high urinary losses of sodium and negative sodium balance. Sodium intakes greater than those currently recommended by the American Academy of Pediatrics are needed to achieve a significant positive sodium balance in this population.
Authors: Cornelia Späth; Elisabeth Stoltz Sjöström; Fredrik Ahlsson; Johan Ågren; Magnus Domellöf Journal: Pediatr Res Date: 2016-12-09 Impact factor: 3.756