A Quantitative Study of Transport of Surfactant Boli in a Three-Dimensional Lung Model of Neonates.

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 its side during the procedure. Our study offers both a novel lung airway model and new 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.