Endogenous nitric oxide production in the airways of preterm and term infants.

Few studies have measured endogenous nitric oxide exhaled from the respiratory system of newborn infants. We measured exhaled nitric oxide (eNO) in the first 48 h of life in 24 (13 preterm, 11 term) spontaneously breathing (online method) newborns using a chemoluminescence analyzer. There was a significant difference in the eNO concentration between term and preterm healthy infants in the first 2 days of life (repeated measures analysis of variance, p < 0.05). In term infants there is a peak eNO production in the first hours of life, suggesting a potential role in postnatal adaptation, while in preterm infants eNO production is almost absent at birth, and then gradually increases. Copyright 2003 S. Karger AG, Basel