Oscillatory mechanics trajectory in very preterm infants: a cohort study

The aim of this study was to describe the trajectory of oscillatory mechanics from the first week of life to term equivalent and evaluate whether oscillatory mechanics are associated with simultaneous lung disease in infants ≤32 weeks gestation.

In this observational, longitudinal study, we enrolled 66 infants. Forced oscillations were applied using a neonatal mechanical ventilator (Fabian HFOi) that superimposed oscillations (10 Hz, amplitude 2.5 cmH₂O) on a positive end-expiratory pressure (PEEP). Measurements were performed at 5-7-9 cmH₂O of PEEP or the clinical pressure ±2 cmH₂O; they were repeated at 7, 14, 28 post-natal days, and 36 and 40 weeks post-menstrual age (PMA).

The mean (range) gestational age of study participants was 29.2 (22.9-31.9) weeks. Nineteen infants (29%) developed bronchopulmonary dysplasia (BPD). Respiratory system reactance was significantly lower (lower compliance), and respiratory system resistance was significantly higher in infants with developing BPD from 7 post-natal days to 36 weeks PMA. All oscillatory mechanics parameters were significantly associated with the simultaneous respiratory severity score (p < 0.001 for all).

Serial measurements of oscillatory mechanics allow differentiating lung function trajectory in infants with and without evolving BPD. Oscillatory mechanics significantly correlate with the severity of simultaneous lung disease.

The results of the present study suggest that respiratory system reactance, as assessed by respiratory oscillometry, allows the longitudinal monitoring of the progression of lung disease in very premature infants. This paper describes for the first time the trajectory of oscillatory mechanics in very preterm infants with and without evolving bronchopulmonary dysplasia from the first week of life to term equivalent. Serial respiratory oscillometry measurements allow the identification of early markers of evolving bronchopulmonary dysplasia and may help personalizing the respiratory management strategy.