Prolonged mechanical ventilation induces pulmonary inflammation in preterm infants.

Lung inflammation plays an important role in the pathogenesis of chronic lung disease in preterm infants. To test the hypothesis that prolonged mechanical ventilation induces pulmonary inflammation, we analyzed pro- and anti-inflammatory mediators in bronchoalveolar lavage fluid obtained from ventilated preterm infants having respiratory distress syndrome. Our results show a strong correlation between the duration of mechanical ventilation and the amount of proinflammatory mediators. However, the anti-inflammatory cytokine interleukin 10 remained stable during the whole period of mechanical ventilation. These data support the hypothesis that prolonged mechanical ventilation contributes to the development of chronic lung disease by the induction of lung inflammation without adequate stimulation of the counterregulatory cytokine interleukin 10 in preterm infants with respiratory distress syndrome.