Discussion
This prospective study of children with a tracheostomy found that the
diagnosis of BPD had a statistically significant impact on time to
ventilator liberation as well as decannulation. Children with BPD
obtaining a tracheostomy required increased duration of ventilation and
took longer to achieve decannulation compared to non-BPD children.
Additionally, BPD was associated with a lower hazard of mortality,
although this effect was influenced by the presence of pulmonary
hypertension. This data can further guide clinicians as they care for
this critical population of tracheostomy patients.
The presence of BPD was associated with an increased time to ventilator
liberation. Prior studies have similarly demonstrated that successful
liberation from the ventilator is likely within the first few years of
life across patients with different classes of BPD
severity.17,20 While these findings are encouraging,
it remains important to note that increased durations of mechanical
ventilation are likely to be required by children with BPD. This
increased duration of mechanical ventilation can have a significant
impact on not only the quality of life of the patient, but also their
caregivers. These impacts manifest as patients and their families
navigate challenges associated with medical equipment, physician visits,
financial responsibilities, and potential complications such as
infections that may necessitate readmission.4,13,25 In
order to improve care for this vulnerable population, physicians should
recognize how social determinants of health can impact outcomes. Further
studies examining these factors will be beneficial when managing BPD
patients with a tracheostomy.
Children with BPD on mechanical ventilation had increased times to
tracheostomy decannulation. Patients who undergo tracheostomy are more
likely to be medicaly complex and thus more likely to experience higher
rates of complications due to the presence of comorbid
conditions.33,34 Moreover, children with a
tracheostomy for respiratory support in the setting of BPD have higher
rates of hospitalization and morbidity.14 These
findings suggest that BPD is associated with an increased duration that
a tracheostomy remains in place. This may be due to higher rates of
complications in pediatric tracheostomy patients such as respiratory
infections and subsequent readmissions that have been examined in prior
studies.25 Of note, the median time to ventilator
liberation and eventual decannulation for our study population was 2.3
and 1.9 years, respectively. This result is likely the consequence of
children who did not require mechanical ventilation undergoing
decannulation earlier than their peers who did require advanced
respiratory support which adds to the overall time that the tracheostomy
is in place.35 At present there are no studies that
have directly examined the relationship between the presence of BPD,
pulmonary hypertension, and time to decannulation. However, existing
literature does suggest that decannulation within the first few years of
life is likely across a spectrum of BPD severity with excellent survival
rates.17, 28 The addition of BPD to a complex patient
profile may also contribute to the development of other exacerbating
pathologies such as pulmonary hypertension that worsen overall clinical
status.5,16,18 It is likely that the added complexity
of BPD and its sequelae contributed to the increased time to
decannulation amongst BPD patients when compared to non-BPD patients
within this study. Further studies directed at intervention strategies
to reduce complications associated with BPD may provide further insight
into these findings and allow for better care of this vulnerable patient
population.
While the presence of BPD was associated with a decreased mortality
hazard ratio, the additional diagnosis of pulmonary hypertension was
associated with an increased mortality hazard ratio. Prior studies have
found an increased risk of mortality amongst patients with moderate to
severe BPD and comorbid pulmonary hypertension.36,37This increase in mortality has previously been hypothesized as being
related to prolonged hypoxemic events that are associated with
BPD-associated pulmonary hypertension.38 These
recurrent episodes of hypoxemia may also offer insight into the
increased prevalence of disability identified amongst patients within
the present sample. While adequate oxygenation and pulmonary function is
of well-understood importance in premature newborns, it may play an even
more significant role in long term outcomes than previously anticipated
in those with BPD and pulmonary hypertension. Thus, the increased
prevalence of disability identified by this study as well as
others8,39 suggests that neurodevelopmental follow up
to evaluate for additional care needs may be warranted to optimize
outcomes for this vulnerable patient population, even after eventual
ventilator liberation and decannulation.
There are multiple limitations to this study. First, this study was
conducted using data with unidentified factors influencing the outcomes
of this study not controlled for during analysis. Additionally, given
the variance of criteria for diagnosis of BPD across institutions, these
findings may not be generalizable to all populations based on
non-homogenous standards of diagnosis as previously discussed. To
minimize misclassification bias, multiple authors of this study verified
diagnoses and other key datapoints collected from patient charts. The
risk of misclassification is also mitigated by the fact that this data
is from a single institution and is thus not as susceptible to
variations in diagnostic criteria. Finally, children who have undergone
tracheostomy are more likely to present with multiple medical
comorbidities that may complicate the respiratory-related outcomes
examined within this sample. Though variables of interest like BPD and
pulmonary hypertension were directly examined, it is possible that there
are other unidentified factors that influenced the outcomes of this
study. Despite these limitations, this study allows for the exploration
of the relationship between BPD and comorbidities like pulmonary
hypertension and their associations with key respiratory outcome
measures. This study was also conducted utilizing data from patients who
were cared for at a tertiary care children’s hospital with a Level I
pediatric trauma center and Level IV neonatal intensive care unit
(NICU). As a result, this study was able to capture important data on a
high number of clinically complex patients, thus offering further
information on a particularly vulnerable population with a stable
incidence across the United States.
Overall, this information can generalize and inform individuals caring
for pediatric tracheostomy patients with BPD and pulmonary hypertension.
The presence of these two comorbid diseases did impact
respiratory-related outcomes, particularly time to decannulation, as
anticipated. Thus, this data may inform teams caring for this vulnerable
patient population as they seek to provide high-quality long-term care
for these children with regards to ventilator liberation and
decannulation. Regarding future research opportunities, comorbidities
like subglottic stenosis or reasons for delays in decannulation such as
a failed sleep study thus requiring adenotonsillectomy could be further
explored. These efforts could further guide care efforts for this
patient population and eventually lead to optimization of existing
protocols for these individuals.