DISCUSSION:
In the current study, we noted a significant association between the presence of a hemodynamically significant PDA and extubation failure, which is in concurrence with previous studies [16, 17] that have reported a similar association.
We speculate that PDA may contribute to extubation failure due to pulmonary edema, leading to increased work of breathing. The PDA may become more hemodynamically significant after reduction of mean airway pressure applied to the lungs after extubation.
It is not known if proactively evaluating for PDA prior to extubation and its treatment would be associated with an improved likelihood of successful extubation. The data from the current study are hypothesis generating and may serve as a basis for future prospective observational and randomized controlled trials to evaluate the role of treatment for PDA prior to extubation to improve the cardiorespiratory outcomes of these infants.
There is no consensus on the definition of extubation success for premature infants. We defined extubation success as need for re intubation within five days of extubation as a significant proportion (25%) of infants might fail extubation beyond 48-72 hours of extubation. [13]
Current study had some limitations. As this was an observational study, we cannot establish a cause-and-effect relationship between presence of PDA and extubation failure. Endotracheal intubation, extubation and reintubation, were at the discretion of the primary clinical team. Strengths of the current study include inclusion of all eligible infants using well defined criteria with no selection bias. All infants were born in a single center that reduced the variability in clinical practice.