Dysnatremia in extremely low birth weight infants is associated with multiple adverse outcomes.

OBJECTIVE

The objective of this study is to discern patterns of serum sodium in a broad cohort of extremely low birth weight (ELBW) infants and associate those patterns with hospital outcomes.

STUDY

DESIGN

Retrospective cohort study of ELBW infants from 323 neonatal intensive care units (NICUs) discharged from 2004 to 2014. We included patients who survived at least 7 days and had daily sodium levels available, and categorized infants by their minimum and maximum sodium levels.

RESULTS

We identified 26,871 infants of whom 12,428 met inclusion criteria. Only 1964 (15.8%) maintained eunatremia for the first week. We found most dysnatremias to be associated with increased overall mortality compared with eunatremic patients including moderate hyponatremia (12.9% vs. 8.6%, p < 0.05) and severe hypernatremia (34.8% vs. 8.6%, p < 0.001). Most of these associations were maintained after regression modeling for mortality.

CONCLUSION

Sodium fluctuations occurring within the first week of life are associated with increased mortality.