Finite element model of the tracheal bifurcation during Total Liquid Ventilation: comparison of different ventilation strategies.

Aim of this study was to compare the effects exerted on preterm airways by Total Liquid Ventilation (TLV) performed in different ventilation strategies. A finite element model was developed to investigate the behaviour of preterm lamb airways in the range of pressures applied during TLV when using two different TLV prototypes developed by our research group: a volume controlled piston pump and a newly developed pressure controlled prototype (Pro-Li-Ve). The model allowed the comparison of the effects exerted by the different ventilation settings. Distinct deformation patterns were shown during the respiratory cycle performed with the two devices. Both of them induced a slight increase of the airway lumen during inspiration and a decrease during expiration. However lower expiratory lumen narrowing was recorded with Pro-Li-Ve, with respect to the one induced by the piston pump. In fact, the narrowing induced by Pro-Li-Ve occurred at the beginning of expiration, i.e. when the lungs are totally filled with perfluorocarbon, thus reducing the risk of airway collapse.