Conclusions
Mechanically ventilated neonates born at <30 week GA, with
evidence of BPD requiring dexamethasone to facilitate extubation, had a
lower likelihood of successful extubation by day 14 if at the time of
commencing steroids they were less mature at birth, had higher MAPs and
higher oxygen requirements.
INTRODUCTION
Most extremely preterm neonates require mechanical
ventilation.1 Once they are intubated, the aim is to
extubate as soon as possible to minimise time spent mechanically
ventilated. The desired outcome is to reduce the risk of the development
of chronic lung disease, aka bronchopulmonary dysplasia (BPD), and
associated adverse outcomes.2-4
The chronic lung disease, which often requires further prolonged periods
of intubation, involves inflammatory parenchymal change with incremental
increases in inspired oxygen, inflation pressures and tidal volume to
achieve adequate gas exchange.5 BPD is still common;
occurring in 80% of neonates less than 25 weeks gestational age
(GA).6 The risk is higher in very low birthweight
neonates who remain intubated after 1-2 weeks of age.3Systemic dexamethasone facilitates weaning of invasive ventilatory
support by suppressing inflammation, improving lung compliance, and
decreasing airway resistance.5-8 There are well
documented complications of systemic steroids: gastric perforation and
bleeding, hypertension, hyperglycaemia, poor growth and worse
neurodevelopmental outcome.8-11 Therefore, steroids
are often reserved for neonates who are difficult to extubate from
mechanical ventilation, who exhibit clinical evidence of BPD and are
greater than 7 days of age; and where the risk of BPD is
>50%.12 Clinicians should also aim to
give with the lowest cumulative dose of
steroids.9,13,14
Responses to the initial dexamethasone courses are variable, at times
resulting in dexamethasone treatment that does not facilitate
extubation. There may be factors present at the time of considering
treating the neonate with steroids that are associated with a lesser or
greater chance of successful extubation. If factors are identified that
are associated with a reduction in successful extubation, it may well be
worth electing to wait until circumstances are more favourable. Given
the paucity of research investigating these potential factors, the aim
of our study was to identify, in mechanically ventilated neonates less
than 30 weeks GA with clinical evidence of BPD, predictors that are
associated with a first course of systemic dexamethasone leading to
extubation within 14 days and remaining extubated for at least 7 days.