An individualized approach to sustained inflation duration at birth improves outcomes in newborn preterm lambs

A sustained first inflation (SI) at birth may aid lung liquid clearance and aeration, but the impact of SI duration relative to the volume-response of the lung is poorly understood. We compared three SI strategies: 1) variable duration defined by attaining volume equilibrium using real-time electrical impedance tomography (EIT; SIplat); 2) 30 s beyond equilibrium (SIlong); 3) short 30-s SI (SI30); and 4) positive pressure ventilation without SI (no-SI) on spatiotemporal aeration and ventilation (EIT), gas exchange, lung mechanics, and regional early markers of injury in preterm lambs. Fifty-nine fetal-instrumented lambs were ventilated for 60 min after applying the allocated first inflation strategy. At study completion molecular and histological markers of lung injury were analyzed. The time to SI volume equilibrium, and resultant volume, were highly variable; mean (SD) 55 (34) s, coefficient of variability 59%. SIplat and SIlong resulted in better lung mechanics, gas exchange and lower ventilator settings than both no-SI and SI30. At 60 min, alveolar-arterial difference in oxygen was a mean (95% confidence interval) 130 (13, 249) higher in SI30 vs. SIlong group (two-way ANOVA). These differences were due to better spatiotemporal aeration and tidal ventilation, although all groups showed redistribution of aeration towards the nondependent lung by 60 min. Histological lung injury scores mirrored spatiotemporal change in aeration and were greatest in SI30 group (P < 0.01, Kruskal-Wallis test). An individualized volume-response approach to SI was effective in optimizing aeration, homogeneous tidal ventilation, and respiratory outcomes, while an inadequate SI duration had no benefit over positive pressure ventilation alone

Fixed-Duration versus EIT-determined Volume-Response Defined Sustained Inflation in Preterm Lambs

We compared a standard fixed duration Sustained Inflation (SI) during resuscitation at birth in preterm lambs with two SI guided by real-time volumetric EIT imaging, lasting respectively until volume plateau and until 30s beyond plateau. Global and local end expiratory volume (EEV), lung mechanics and gas exchange were measured. Both the volumetric EIT guided approaches were feasible and resulted in better relative lung aeration

Combining lung ultrasound and oscillatory mechanics for assessing lung disease in very preterm infants

Background: We investigated whether combining lung ultrasound scores (LUSs) and respiratory system reactance (Xrs) measured by respiratory oscillometry explains the severity of lung disease better than individual parameters alone.Methods: We performed a prospective observational study in very preterm infants. Forced oscillations (10 Hz) were applied using a neonatal mechanical ventilator (Fabian HFOi, Vyaire). We used the simultaneous respiratory severity score (RSS = mean airway pressure x FIO2) as a primary outcome. We built linear mixed-effect models to assess the relationship between Xrs z-score, LUS and RSS and compared nested models using the likelihood ratio test (LRT).Results: We enrolled 61 infants (median (Q1, Q3) gestational age = 30.00 (26.86, 31.00) weeks) and performed 243 measurements at a postnatal age of 26 (13, 41) days and postmenstrual age of 33.14 (30.46, 35.86) weeks. Xrs z-score and LUS were independently associated with simultaneous RSS (p &lt; 0.001 for both). The model including Xrs and LUS explained the RSS significantly better than Xrs (p value LRT &lt; 0.001) or LUS alone (p value LRT &lt; 0.001).Conclusions: Combining LUS and Xrs z-score explains the severity of lung disease better than each parameter alone and has the potential to improve the understanding of the underlying pathophysiology

Accuracy of oscillatory pressure measured by mechanical ventilators during high frequency oscillatory ventilation in newborns

Oscillatory pressure (ΔP) measurement during high frequency oscillatory ventilation (HFOV) is technically challenging and influenced by all the components of the measurement system

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

We aimed at investigating whether early lung mechanics in non-intubated infants below 32 weeks of gestational age (GA) are associated with respiratory outcome

Within-breath changes in respiratory system impedance in children with cystic fibrosis

The aim of this study was to assess within-breath respiratory system impedance by the forced oscillation technique (FOT) in children with cystic fibrosis (CF) and relate it to the underlying lung disease

Oscillatory mechanics response to inhaled bronchodilators in very preterm infants: a retrospective study

To identify short-term repeatability of forced oscillation technique (FOT) measurement of lung function, assess the lung function response to bronchodilators (BD) by FOT, prove the concept that only some very preterm infants manifest a change in lung mechanics in response to BD