Changes in respiratory mechanics at birth in preterm infants: A pilot study

Abstract

Objective We aimed to measure lung mechanics at birth by the forced oscillation technique (FOT) for assessment of the initial degree of lung aeration and the short‐term aeration changes after applying different respiratory support strategies. Methods Eighteen preterm infants (gestational age = 29‐36 week) were randomized to receive either continuous positive airway pressure (CPAP) at 5 cmH2O only or combined with a sustained inflation (SI; 15 seconds at 25 cmH2O after 5 seconds of CPAP) at birth. We assessed the respiratory system reactance at 5 Hz (X5; increases with lung volume recruitment at a given distending pressure) at 2, 40, and 150 seconds after initiation of CPAP. k‐Means clustering of the initial X5 value (X5,i) stratified newborn into either infants with lower (lowerX5,i; X5 < −280 cmH2O*s/L) and higher (higherX5,i; X5 > −240 cmH2O*s/L) initial degree of lung volume recruitment. Results Initial values were highly heterogeneous. In the LowerX5,i group, X5 increased with time, with SI‐patients showing significantly higher values at 150 seconds than the non‐SI group (X5 = −89 ± 27 cmH2O vs −274 ± 58 cmH2O). In the higherX5,i group, X5 did not improve with time, regardless of the respiratory strategy, suggesting a lack of lung recruitment. Moreover, 75% of infants receiving SI in the higherX5,i group experienced a transient loss of aeration after the maneuver. Conclusions Preterm newborns present initially with highly heterogeneous lung aeration at birth that significantly impacts the effectiveness of the subsequent lung volume recruitment strategy. FOT may represent a valuable tool for individualizing a respiratory resuscitation at birth as it is noninvasive and may be applied simultaneously to respiratory support.

Oscillatory mechanics at birth for identifying infants requiring surfactant: a prospective, observational trial

“…The technique does not involve estimating the pleural pressure by positioning an oesophagal balloon or evoking the Hering–Breuer inflation reflex for respiratory muscle relaxation. Previous studies demonstrated FOT feasibility in the delivery room [ 31 ] and the NICU, both in intubated patients [ 27 – 29 ] and infants receiving NCPAP [ 30 ]. Moreover, thanks to recent technological advancements, oscillometry can be now integrated into modern mechanical ventilators.…”

“…In particular, studies demonstrated that the total respiratory system reactance (Xrs) measured at frequencies lower than 10 Hz at a given distending pressure is a sensitive and specific indicator of lung volume recruitment [ 19 , 24 ]. FOT measurements are suitable at the bedside in preterm infants during invasive [ 25 – 29 ] and non-invasive respiratory support [ 30 ], and even during respiratory stabilization in the delivery room [ 31 ]. Moreover, oscillometry assessments in the first few days of life can predict respiratory support duration [ 27 , 30 ].…”

2020 year in review: Neonatal pulmonology

“…Their observation that male infants had increased elastance (reduced compliance) may reflect delayed alveolar development, but the variability of the measurements was quite high, and the study sample was quite modest. 1 Veneroni et al 2 tested whether or not sustained inflation at birth (vs. nCPAP) in prematures in mild respiratory distress would durably alter mechanics measured by forced oscillation, finding, as in the study by Kim et al, 1 that the variability of measurements is quite high, with no discernible difference between the two strategies. Given the large changes in lung alveolar fluid that take place at the time of birth, this is to be expected.…”

Pediatric Pulmonology Year in Review 2020: Physiology

“…Veneroni, et al used FO to compare respiratory mechanics in preterm infants treated with continuous positive airway pressure (CPAP) versus CPAP with sustained inflations of 25 cmH2O for 15 seconds [5]. Infants presented with highly heterogeneous degrees of lung aeration at birth, limiting their ability to use FO to assess ventilation strategies.…”