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.