Extremely low-dose dexamethasone to facilitate extubation in mechanically ventilated preterm babies

Bronchopulmonary dysplasia (BPD) is a major respiratory complication of extreme prematurity. Dexamethasone is effective in reducing ventilation requirements in babies with BPD, but follow-up studies have raised concerns about long-term neurological sequelae. Few studies have investigated the lowest dose effective for weaning from mechanical ventilation.

Between January 2004 and December 2008 the practice in a tertiary neonatal unit was to use extremely low doses of dexamethasone for severe BPD, commencing at 0.05 mg/kg/day and decreasing over 9 days, with a cumulative dose of 0.24 mg/kg. The objective of this observational study was to assess the effectiveness of the extremely low-dose course in facilitating extubation.

The babies who had received extremely low-dose dexamethasone to facilitate weaning from mechanical ventilation were identified. Details of treatment and respiratory support were recorded. Serial oxygenation indices (OI) during the dexamethasone course were calculated, and these were analysed to assess the effect of treatment on ventilation requirements.

One hundred and ninety extremely preterm babies were admitted during this 5-year period. Sixteen babies received extremely low-dose dexamethasone. The median gestation was 25 weeks and the median birth weight was 644 g. Before starting dexamethasone, the median OI was 10.6, but by day 7 of treatment it had fallen to 5.4. By the end of the course, 12 of the 16 babies had been successfully extubated.

This short dexamethasone course appears effective in facilitating extubation. Randomised trials with long-term follow-up are needed to determine the role of extremely low-dose dexamethasone in preterm babies with evolving BPD.