Tracheal colonization in preterm infants supported with nasal continuous positive airway pressure

The aim of this study was to examine endotracheal bacteriological status in premature infants who are supported by nasal continuous positive airway pressure (CPAP) without any history of tracheal intubation.

In this prospective study, we enrolled 60 premature infants with respiratory distress; of these, 30 were supported by CPAP without tracheal intubation, and 30 were intubated and mechanically ventilated. Infants were enrolled at a postnatal age of < 24 h. Endotracheal (ET) cultures were taken at 24 h and at the 5th day of life. In the CPAP group, a suction catheter was sterilely inserted into the trachea while directly visualizing the vocal cords using a laryngoscope.

ET cultures taken on the 1st day of life showed colonization in 7/30 (23%) in the CPAP group versus 19/30 (63%) in the mechanically ventilated group (P= 0.002). Tracheal cultures on day 5 were positive in 5/30 (17%) and 11/30 (37%), respectively (P= 0.093). Klebsiella ssp. represented the most frequently isolated organism in both groups. A positive tracheal culture at 5 days was associated with a longer duration of respiratory support in the CPAP group (P= 0.05) but not in the ventilation group. Endotracheal culture at 5 days was associated with mortality in the ventilation group (8/11 vs 5/19, P= 0.02), but not in the CPAP group (1/5 vs 2/25, P= 0.45). Early endotracheal cultures did not relate with mortality in either of the groups.

The trachea of premature infants supported with CPAP is at risk for bacterial colonization. Predisposing factors, mechanisms and clinical implications of these novel findings need to be studied.