Noninvasive Oscillometry to Measure Pulmonary Mechanics in Preterm Infants

Travers, Colm P.; Klinger, Andrew; Aban, Inmaculada; Hoover, Wynton; Carlo, Waldemar A.; Ambalavanan, Namasivayam

doi:10.1164/rccm.202101-0226le

Cited by 4 publications

(5 citation statements)

References 9 publications

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“…Even though preterm infants are expected to have lower Xrs values than their term peers, in the referenced studies, measurements were performed in the first 3 days of life, when the transition to postuterine life may still affect lung mechanics. Moreover, our Rrs values were similar, and our Xrs values were higher than those reported by Travers et al in preterm infants off respiratory support 13 . By contrast, our Xrs values were similar to those found by Lavizzari et al in the first hours after birth in a population of infants below 35 weeks gestation using the same device used in the present study at the same distending pressure 7 .…”

Section: Discussionsupporting

confidence: 88%

“…We studied clinically stable nonintubated subjects who did not develop respiratory complications. Preterm infants have higher respiratory system impedance than term infants, even if they are off respiratory support 13 . Therefore, the identified values are not intended as normative ranges from a healthy population but as reference values that allow comparing Rrs and Xrs in patients of different ages or examining the progression of lung function within the same patient over time.…”

Section: Discussionmentioning

confidence: 99%

“…We acknowledge that the device is not available in all countries yet, which limits the applicability of the methodology. Custom‐made systems 16,17 and customized versions of systems for children and adults 13 , 14 have also been used to assess oscillatory mechanics in infants. Future studies are warranted to demonstrate the reproducibility of results using different systems.…”

Section: Discussionmentioning

confidence: 99%

“…For each measurement, we selected a minimum of three consecutive breaths free from artifacts; we then computed the median Rrs and Xrs value and the Rrs coefficient of variation of the selected breath. We used a CVr threshold of 25% for the validity of the measurement based on previous studies 13,14 …”

Section: Methodsmentioning

confidence: 99%

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Oscillatory mechanics in very preterm infants on continuous positive airway pressure support: Reference values

Zannin

Rigotti

Neumann

et al. 2022

Pediatric Pulmonology

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Objective To create reference values for respiratory system resistance (Rrs) and reactance (Xrs) measured by the forced oscillation technique (FOT) in nonintubated very preterm infants. Design Retrospective analysis of data collected as part of prospective observational studies in two centers. Setting Tertiary neonatal intensive care units. Patients Non‐intubated infants below 32 weeks' gestation age who did not develop bronchopulmonary dysplasia. Interventions We applied FOT using a mechanical ventilator (Fabian HFOi; Vyaire) that superimposed small‐amplitude oscillations (10 Hz) on a continuous positive airway pressure of 3 and 5 cmH2O. Measurements were performed during regular tidal breathing using a face mask. Main outcome measures We analyzed 198 measurements performed between 7 postnatal days and 40 weeks postmenstrual age (PMA) in 85 infants, with a median (Q1, Q3) gestational age of 30.43 (29.14, 31.18) weeks. Logarithmic transformations were applied to Rrs and Xrs, and the relationship between transformed impedance values and demographic factors was examined by backwards stepwise linear regression. Results In univariable analysis, transformed Xrs was significantly associated with PMA, postnatal age, weight, and length, while Rrs was not. The best multivariable regression model estimating transformed Xrs (cmH2O*s/L) at continuous positive airway pressure (CPAP) = 5 cmH2O was: Ln(50 − Xrs) = 4.536 − 0.009 x PMA − 0.014 x weight z‐score. SEE = 0.053, R2 = 0.36. The mean (SD) Rrs at CPAP = 5 cmH2O was 33.63 (5.28) cmH2O*s/L. Conclusion We have established reference values for Rrs and Xrs at 10 Hz in nonintubated preterm neonates on continuous positive airway pressure support.

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Section: Discussionsupporting

confidence: 88%

Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

See 2 more Smart Citations

Oscillatory mechanics in very preterm infants on continuous positive airway pressure support: Reference values

Zannin

Rigotti

Neumann

et al. 2022

Pediatric Pulmonology

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“…The wave-tube principle ( 29 ) employed in the present work is particularly advantageous in the measurements of high Zrs, and it was considered as the gold standard technique in the comparison of commercially available oscillometry devices ( 30 ). Device dependence might have been the primary reason for the large differences in the Rrs and Xrs values reported recently ( 13 , 31 ), compared with that from the present and previous measurements with the wave-tube technique ( 2 , 4 , 5 , 7 ).…”

Section: Discussioncontrasting

confidence: 54%

Respiratory Oscillometry in Newborn Infants: Conventional and Intra-Breath Approaches

et al. 2022

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BackgroundOscillometry has been employed widely as a non-invasive and standardized measurement of respiratory function in children and adults; however, limited information is available on infants.AimsTo establish the within-session variability of respiratory impedance (Zrs), to characterize the degree and profile of intra-breath changes in Zrs and to assess their impact on conventional oscillometry in newborns.Methods109 healthy newborns were enrolled in the study conducted in the first 5 postpartum days during natural sleep. A custom-made wave-tube oscillometry setup was used, with an 8–48 Hz pseudorandom and a 16 Hz sinusoidal signal used for spectral and intra-breath oscillometry, respectively. A resistance-compliance-inertance (R-C-L) model was fitted to average Zrs spectra obtained from successive 30-s recordings. Intra-breath measures, such as resistance (Rrs) and reactance (Xrs) at the end-expiratory, end-inspiratory and maximum-flow points were estimated from three 90-s recordings. All natural and artifact-free breaths were included in the analysis.ResultsWithin-session changes in the mean R, C and L values, respectively, were large (mean coefficients of variation: 10.3, 20.3, and 26.6%); the fluctuations of the intra-breath measures were of similar degree (20–24%). Intra-breath analysis also revealed large swings in Rrs and Xrs within the breathing cycle: the peak-to-peak changes amounted to 93% (range: 32–218%) and 41% (9–212%), respectively, of the zero-flow Zrs magnitude.DiscussionIntra-breath tracking of Zrs provides new insight into the determinants of the dynamics of respiratory system, and highlights the biasing effects of mechanical non-linearities on the average Zrs data obtained from the conventional spectral oscillometry.

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