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Abstract Neonatal respiratory distress syndrome is mainly treated with the intratracheal delivery of pulmonary surfactants. The success of the therapy depends on the uniformity of distribution and efficiency of delivery of the instilled surfactant solution to the respiratory zone of the lungs. Direct imaging of the surfactant distribution and quantifying the efficiency of delivery is not feasible in neonates. To address this major limitation, we designed an eight-generation computational model of neonate lung airway tree using morphometric and geometric data of human lungs and fabricated it using additive manufacturing. Using this model, we performed systematic studies of delivery of a clinical surfactant either at a single aliquot or at two aliquots under different orientations of the airway tree in the gravitational space to mimic rolling a neonate on their side during the procedure. Our study offers novel insights into effects of the orientation of the lung airways and presence of a pre-existing surfactant film on how the instilled surfactant solution distributes in airways.
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Microscale distribution and dynamic surface tension of pulmonary surfactant normalize the recruitment of asymmetric bifurcating airways
We investigate the influence of bifurcation geometry, asymmetry of daughter airways, surfactant distribution, and physicochemical properties on the uniformity of airway recruitment of asymmetric bifurcating airways. To do so, we developed microfluidic idealized in vitro models of bifurcating airways, through which we can independently evaluate the impact of carina location and daughter airway width and length. We explore the uniformity of recruitment and its relationship to the dynamic surface tension of the lining fluid and relate this behavior to the hydraulic (P Hyd ) and capillary (P Cap ) pressure drops. These studies demonstrate the extraordinary importance of P Cap in stabilizing reopening, even in highly asymmetric systems. The dynamic surface tension of pulmonary surfactant is integral to this stability because it modulates P Cap in a velocity-dependent manner. Furthermore, the surfactant distribution at the propagating interface can have a very large influence on recruitment stability by focusing surfactant preferentially to specific daughter airways. This implies that modification of the surfactant distribution through novel modes of ventilation could be useful in inducing uniformly recruited lungs, aiding in gas exchange, and reducing ventilator-induced lung injury. NEW & NOTEWORTHY The dynamic surface tension of pulmonary surfactant is integral to the uniformity of asymmetric bifurcation airway recruitments because it modulates capillary pressure drop in a velocity-dependent manner. Also, the surfactant distribution at the propagating interface can have a very large influence on recruitment stability by focusing surfactant preferentially to specific daughter airways. This implies that modification of the surfactant distribution through novel modes of ventilation could be useful in inducing uniformly recruited lungs, reducing ventilator-induced lung injury.
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- Award ID(s):
- 1706801
- PAR ID:
- 10124640
- Date Published:
- Journal Name:
- Journal of Applied Physiology
- Volume:
- 122
- Issue:
- 5
- ISSN:
- 8750-7587
- Page Range / eLocation ID:
- 1167 to 1178
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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- Free Publicly Accessible Full Text
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Accepted Manuscript1.0
- Journal Article:
- https://doi.org/10.1152/japplphysiol.00543.2016
