DISCUSSION
The current study noted that 24% of the extreme preterm infants failed their first elective extubation.  These results are comparable to previous studies of extremely preterm infants, which have demonstrated extubation failure of approximately 23 to 40%. 7-11.The time taken to achieve comparable pre-extubation respiratory support (RSS: 4 days with IQR of 2-7 days; VI: 7 days with IQR of 3-14 days) is concerning and provides an estimate of the significant respiratory setback among infants who fail extubation. All respiratory and blood gas parameters were significantly worse at both 24 and 72 hours post re-intubation when compared with pre-extubation levels.
There could be multiple potential reasons for respiratory setback among these infants after failed extubation. It is possible that some infants develop atelectasis and loss of functional residual capacity due to lack of adequate respiratory support post extubation or during the intubation attempt.20 Extubation failure requiring reintubation is not a benign process and may be associated with multiple complications. Endotracheal intubation is associated with discomfort to the patient, and wrong position of endotracheal tube can cause airway trauma along with hemodynamic instability.21-24 There is also a risk of introduction of infectious micro-organisms every time a new endotracheal tube is inserted.25 Reported rates of successful intubations for preterm neonates are between 50% and 73% with a long time (51 ± 28 seconds) needed for intubation.26,27 Endotracheal intubations have also been associated with alterations in brain function as monitored by electroencephalography.28 The current study provides more insight into the pathophysiology of failed extubation and outcomes of preterm infants related to respiratory setback.
This study has some limitations. Endotracheal intubation, extubation, and reintubation were at the discretion of the clinical team. We did not have data on occurrence of other complications during peri-extubation period such as sepsis, and NEC. We did not explore the reasons for extubation failure in this study. Also, there was no sub-group
analysis done based on the timing of reintubation, other than the predefined criteria of 5 days. All infants were born in a single center, which reduces generalizability of the study. Strengths of the study were inclusion of all eligible infants using pre-defined criteria with no selection bias, and use of objective criteria to compare the respiratory status of these infants in relation to extubation failure.