Effect of betamethasone, surfactant, and positive end-expiratory pressures on lung aeration at birth in preterm rabbits

Crawshaw, Jessica R.; Hooper, Stuart B.; Pas, Arjan B. te; Allison, Beth J.; Wallace, Megan Jane; Kerr, Lauren T.; Lewis, Robert A.; Morley, C J; Leong, Andrew; Kitchen, Marcus John

doi:10.1152/japplphysiol.01043.2015

Cited by 4 publications

(4 citation statements)

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“…While intratracheal surfactant application improves lung aeration as well as ventilation homogeneity,34 35 we did not see a meaningful effect of prophylactic SN on physiological outcomes. Any effects towards a different ventilation distribution were marginal and vanished after correction for multiple testing.…”

Section: Discussioncontrasting

confidence: 62%

Prophylactic surfactant nebulisation for the early aeration of the preterm lung: a randomised clinical trial

Gaertner

Minocchieri

Waldmann

et al. 2022

Arch Dis Child Fetal Neonatal Ed

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ObjectiveThe effect of prophylactic surfactant nebulisation (SN) is unclear. We aimed to determine whether prophylactic SN improves early lung aeration.DesignParallel, randomised clinical trial, conducted between March 2021 and January 2022.SettingDelivery room (DR) of a tertiary neonatal centre in Zurich, Switzerland.PatientsPreterm infants between 260/7and 316/7weeks gestationInterventionsInfants were randomised to receive positive distending pressure alone or positive distending pressure and additional SN (200 mg/kg; poractant alfa) using a customised vibrating membrane nebuliser. SN commenced with the first application of a face mask immediately after birth.Main outcome measuresPrimary outcome was the difference in end-expiratory lung impedance from birth to 30 min after birth (∆EELI30min). EELI correlates well with functional residual capacity. Secondary outcomes included physiological and clinical outcomes.ResultsData from 35 infants were collected, and primary outcome data were analysed from 32 infants (n=16/group). Primary outcome was not different between intervention and control group (median (IQR): 25 (7–62) vs 10 (0–26) AU/kg, p=0.21). ∆EELI was slightly higher in the intervention group at 6 and 12 hours after birth, particularly in the central areas of the lung. There were no differences in cardiorespiratory and clinical parameters. Two adverse events were noted in the intervention group.ConclusionsProphylactic SN in the DR did not significantly affect ∆EELI30minand showed only minimal effects on lung physiology. Prophylactic SN in the DR was feasible. There were no differences in clinical outcomes.Trial registration numberNCT04315636.

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Section: Discussioncontrasting

confidence: 62%

Prophylactic surfactant nebulisation for the early aeration of the preterm lung: a randomised clinical trial

Gaertner

Minocchieri

Waldmann

et al. 2022

Arch Dis Child Fetal Neonatal Ed

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“…Kittens were mechanically ventilated to avoid the variability associated with spontaneous breathing and to assess the effect of elevated airway liquid volumes on respiratory mechanics. Following imaging onset, ventilation commenced with intermittent positive pressure ventilation, commencing with a peak inflation pressure (PIP) of 25 cmH 2O, a positive end-expiratory pressure (PEEP) of 5 cmH2O, and inspiratory and expiratory times of 0.5 s. The PIP was increased to achieve a Vt of 8 ml/kg, which was measured directly from the plethysmograph, as previously described (5). During the ventilation period, following the initial 5-cmH 2O PEEP stage (5PEEP-I), the PEEP was decreased to 3 cmH2O (3PEEP) and then to 0 cmH2O (0PEEP) before it was returned to 5 cmH2O (5PEEP-F; Fig.…”

Section: Ventilation Protocolmentioning

confidence: 99%

Elevated airway liquid volumes at birth: a potential cause of transient tachypnea of the newborn

McGillick

Lee

Yamaoka

et al. 2017

Journal of Applied Physiology

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Excessive liquid in airways and/or distal lung tissue may underpin the respiratory morbidity associated with transient tachypnea of the newborn (TTN). However, its effects on lung aeration and respiratory function following birth are unknown. We investigated the effect of elevated airway liquid volumes on newborn respiratory function. Near-term rabbit kittens (30 days gestation; term ~32 days) were delivered, had their lung liquid-drained, and either had no liquid replaced (control; = 7) or 30 ml/kg of liquid re-added to the airways [liquid added (LA); = 7]. Kittens were mechanically ventilated in a plethysmograph. Measures of chest and lung parameters, uniformity of lung aeration, and airway size were analyzed using phase contrast X-ray imaging. The maximum peak inflation pressure required to recruit a tidal volume of 8 ml/kg was significantly greater in LA compared with control kittens (35.0 ± 0.7 vs. 26.8 ± 0.4 cmHO, < 0.001). LA kittens required greater time to achieve lung aeration (106 ± 14 vs. 60 ± 6 inflations, = 0.03) and had expanded chest walls, as evidenced by an increased total chest area (32 ± 9%, < 0.0001), lung height (17 ± 6%, = 0.02), and curvature of the diaphragm (19 ± 8%, = 0.04). LA kittens had lower functional residual capacity during stepwise changes in positive end-expiratory pressures (5, 3, 0, and 5 cmH0). Elevated lung liquid volumes had marked adverse effects on lung structure and function in the immediate neonatal period and reduced the ability of the lung to aerate efficiently. We speculate that elevated airway liquid volumes may underlie the initial morbidity in near-term babies with TTN after birth. Transient tachypnea of the newborn reduces respiratory function in newborns and is thought to result due to elevated airway liquid volumes following birth. However, the effect of elevated airway liquid volumes on neonatal respiratory function is unknown. Using phase contrast X-ray imaging, we show that elevated airway liquid volumes have adverse effects on lung structure and function in the immediate newborn period, which may underlie the pathology of TTN in near-term babies after birth.

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“…Aeration of the gasless fluid-filled lung is the critical event at birth, triggering the rapid changes in the respiratory and vascular systems necessary to adapt to extrauterine life. Aeration is a complex process dependent on several factors, including developmental and disease state of the lung (15), spontaneous breathing activity (24), expiratory braking (24), effective lung fluid reabsorption (1), effectiveness of positive pressure ventilatory support (15, 25b, 25c, 27, 28, 32), and/or pharma-cological treatments (2,30,33,34). Phase contrast X-ray imaging has shown that this process is initially driven by the transpulmonary pressure that first moves the fluid from the central airways to the lung periphery (10).…”

Section: Introductionmentioning

confidence: 99%

Respiratory mechanics during initial lung aeration at birth in the preterm lamb

Veneroni

Tingay

McCall

et al. 2020

American Journal of Physiology-Lung Cellular and Molecular Phys

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Despite recent insights into the dynamic processes during lung aeration at birth, several aspects remain poorly understood. We aimed to characterize changes in lung mechanics during the first inflation at birth and their relationship to changes in lung volume. Intubated preterm lambs (gestational age, 124–127 days; n = 17) were studied at birth. Lung volume changes were measured by electrical impedance tomography (VL EIT). Respiratory system resistance (R5) and oscillatory compliance (Cx5) were monitored with the forced oscillation technique at 5 Hz. Lambs received 3–7 s of 8 cmH2O of continuous distending pressure (CDP) before delivery of a sustained inflation (SI) of 40 cmH2O. The SI was then applied until either Cx5 or the VL EIT or the airway opening volume was stable. CDP was resumed for 3–7 s before commencement of mechanical ventilation. The exponential increases with time of Cx5 and VL EIT from commencement of the SI were characterized by estimating their time constants (τCx5 and τVL EIT, respectively). During SI, a fast decrease in R5 and an exponential increase in Cx5 and VL EIT were observed. Cx5 and VL EIT provided comparable information on the dynamics of lung aeration in all lambs, with τCx5 and τVL EIT being highly linearly correlated ( r2 = 0.87, P < 0.001). Cx5 and VL EIT decreased immediately after SI. Despite the standardization of the animal model, changes in Cx5 and R5 both during and after SI were highly variable. Lung aeration at birth is characterized by a fast reduction in resistance and a slower increase in oscillatory compliance, the latter being a direct reflection of the amount of lung aeration.

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Effect of betamethasone, surfactant, and positive end-expiratory pressures on lung aeration at birth in preterm rabbits

Cited by 4 publications

References 53 publications

Prophylactic surfactant nebulisation for the early aeration of the preterm lung: a randomised clinical trial

Prophylactic surfactant nebulisation for the early aeration of the preterm lung: a randomised clinical trial

Elevated airway liquid volumes at birth: a potential cause of transient tachypnea of the newborn

Respiratory mechanics during initial lung aeration at birth in the preterm lamb

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