Forced oscillation measurements in the first week of life and pulmonary outcome in very preterm infants on noninvasive respiratory support

Background We aimed at investigating whether early lung mechanics in non-intubated infants below 32 weeks of gestational age (GA) are associated with respiratory outcome. Methods Lung mechanics were assessed by the forced oscillation technique using a mechanical ventilator (Fabian HFOi, ACUTRONIC Medical Systems AG, Hirzel, Switzerland) that superimposed small-amplitude oscillations (10 Hz) on a continuous positive airway pressure. Measurements were performed during regular tidal breathing using a face mask on days 2, 4, and 7 of life. Respiratory system resistance (Rrs) and reactance (Xrs) were computed from flow and pressure. Results One hundred and seventy-seven measurements were successfully performed in 68 infants. Infants had a mean (range) GA of 29.3 (24.1–31.7) weeks and a birth weight of 1257 (670–2350)g. Xrs was associated with the duration of respiratory support ( R 2 = 0.39, p < 0.001). A multilevel regression model, including Xrs and GA, explained the duration of respiratory support better than GA alone ( R 2 = 0.51 vs. 0.45, p = 0.005, likelihood ratio test). Conclusion Assessment of Xrs in the first week of life is feasible and improves prognostication of respiratory outcome in very preterm infants on noninvasive respiratory support.