Effects of Early Phosphorus Intake on Respiratory Distress in Extremely Low-Birth-Weight Infants

Abstract

Purpose This study was aimed to investigate the effect of early phosphorus intake on respiratory distress in extremely low-birth-weight infants (ELBWIs) with a high incidence of hypophosphatemia. Methods We performed a retrospective study to target 164 ELBWIs admitted to the neonatal intensive care unit in Seoul National University Children’s Hospital. Birth characteristics, nutritional intake, and electrolyte levels during the first week were investigated as predictors that would affect the clinical outcomes. The correlations among invasive ventilation at postnatal age of 2 weeks, moderate-to-severe bronchopulmonary dysplasia (BPD), and phosphorous intake were analyzed. Results Hypophosphatemia (phosphorus level <4 mg/dL) was observed in 72.0% of the subjects. The rates of invasive ventilation (P=0.001) and moderate-to-severe BPD (P=0.005) were significantly lower in the high phosphorus intake group (≥0.7 mM/kg/day) than in the low phosphorus intake group (<0.7 mM/kg/day). Phosphorus intake during the first week was a significant factor affecting invasive ventilation at 2 weeks of age (adjusted odds ratio [OR], 8.212; 95% confidence interval [CI], 2.256 to 28.896; P=0.001) and moderate-to-severe BPD (adjusted OR, 3.402; 95% CI, 1.274 to 9.084; P=0.015). Conclusion Early insufficient phosphorus intake confers a significantly higher risk with invasive ventilation at 2 weeks of age and moderate-to-severe BPD. Therefore, early sufficient phosphorus supply may improve respiratory outcomes in ELBWIs.

Keywords

• infant, extremely low birth weight
• phosphorus
• respiratory distress
• bronchopulmonary dysplasia