[Duration of mechanical ventilation and development of bronchopulmonary dysplasia]

Verify the association between duration of mechanical ventilation and development of bronchopulmonary dysplasia in neonates weighting at birth less than 1500 g.

Retrospective study conducted with neonates weighting less than 1500 g at birth submitted to mechanical ventilation. Neonates presenting major birth defects, transferred to other services or died before the 28th day of life were excluded from the study. Three groups were analyzed according to duration of mechanical ventilation: 1 to 7 days, 8 to 14 days and more than 15 days. The chance ratio of developing bronchopulmonary dysplasia was calculated for each group.

From the 216 clinical histories assessed, 121 met the criteria for inclusion in the study. Mean birth weight and gestational age were 1199.8 g and 31.8 weeks. Of all neonates submitted to mechanical ventilation from 1 to 7 days, 15.5% developed bronchopulmonary dysplasia; from 8 to 14 days 60% and from more than 15 days, 88.2%; chance ratios were equal to 0.16; 11.25 and 16.36, respectively.

The chance of a neonate weighting less than 1500 g developing bronchopulmonary dysplasia was 11 times higher in those submitted to mechanical ventilation for up to 14 days. This chance was even higher in those ventilated for more than 15 days. That is why the nursing staff assisting high risk patients should consider the possibility of extubating neonates during their first week of life.