RESUMO
Tracheal epithelial damage, was evaluated in prematures that where intubated and with mechanical ventilation; biopsies were taken in seven preterm neonates; weight was 1100 to 2350; five were by cesarean section, y one via vaginal. Bronchial culture was negative in five, in one Lysteria monocitogena, and in another one Pseudomonas spiralis; biopsy was taken at different times o intubation. Five died because of pneumonia associated to other diseases. In optical and ultrastructural study it was found that with one day of intubation there was cilia loss; with three days of ventilation there was ciliary cells loss, and not ciliary cellular death and there were no cellular unions. In one case with three days of ventilation and 17 days of post-extubation with infection by Pseudomonas, ulcerated zones and edema were found. At 14 days there necrosis zones, increase in collagene. At 17 days there were ulcerated zones to the muscular layer with fibrosis and cellular rests at tracheal path. So, mechanical ventilation and the presence of a catheter, damage bronchial epithelium since the first 24 hours.