Objective and study design: Successful adaptation to air breathing at birth depends on rapid absorption of fetal lung liquid that is mediated by activation of amiloride-sensitive sodium ion channels. To test the relationship between respiratory epithelial Na+ transport and development of respiratory distress syndrome (RDS), we measured nasal transepithelial potential difference (PD) in 31 very premature (≤30 weeks of gestation) newborn infants. Infants were retrospectively assigned to RDS (22 infants) and non-RDS (9 infants) groups on the basis of clinical and chest x-ray criteria. Results: Maximal nasal epithelial PD increased with birth weight (- 1.2 mV/100 gm) and was lower in infants with RDS (-16.5 ± 0.6 mV) than in those without RDS (-22.0 ± 1.3 mV). Infants without RDS had PD values similar to normal fullterm infants. Amiloride inhibition of PD, an index of Na+ absorption, was significantly lower, within the first 24 hours of life, in infants in whom RDS developed (3.8 ± 0.2 mV; 29.5% ± 0.8% inhibition) than in those without RD5 (6.1 ± 0.6 mV; 38.6% ± 0.5% inhibition). Maximal and amiloride-sensitive PD returned to normal during the recovery phase of RDS. Conclusions: We conclude that Na+ absorption across nasal epithelium increases with increasing birth weight and that impairment of Na+ absorption across the respiratory epithelia of very premature infants may contribute to the pathogenesis of RDS.
ASJC Scopus subject areas
- Pediatrics, Perinatology, and Child Health