Effect of inhaled gas density on the pendelluft-induced lung injury.

Helium, sulfur hexafluoride-oxygen, and air were modeled to examine the role of the gas density on the pendelluft-induced lung injury (PILI) under high frequency oscillatory ventilation (HFOV). Large eddy simulation coupled with physiological resistance-compliance boundary conditions was applied to capture pendelluft-induced gas entrapment and mechanical stresses in an image-based human lung model. The flow characteristics were strongly dependent on the inspired gas density.

Fluid flow and particle transport in mechanically ventilated airways. Part I. Fluid flow structures.

A large eddy simulation-based computational study of fluid flow and particle transport in upper tracheobronchial airways is carried out to investigate the effect of ventilation parameters on pulmonary fluid flow. Respiratory waveforms commonly used by commercial mechanical ventilators are used to study the effect of ventilation parameters and ventilation circuit on pulmonary fluid dynamics. A companion paper (Alzahrany et al.

Fluid flow and particle transport in mechanically ventilated airways. Part II: particle transport.

The flow mechanisms that play a role on aerosol deposition were identified and presented in a companion paper (Timothy et al. in Med Biol Eng Comput. doi: 10.

A biomechanical model of pendelluft induced lung injury.

Lung ventilation using high frequency oscillatory techniques have been documented to attain adequate gas exchange through various gas transport mechanisms. Among them, the pendelluft flow is considered one of the most crucial mechanisms. In this work, we computationally investigate the induction of abnormal mechanical stresses and a regionally trapped volume of gas due to pendelluft flow.

The role of coupled resistance-compliance in upper tracheobronchial airways under high frequency oscillatory ventilation.

A large eddy simulation (LES) based computational fluid dynamics (CFD) study was conducted to investigate lung lobar ventilation and gas exchange under high frequency oscillatory ventilation conditions. Time-dependent pressure coupled with the airways resistance and compliance (R&C) were imposed as boundary conditions (BCs) in the upper tracheobronchial tree of patient-specific lung geometry. The flow distribution in the left and right lungs demonstrated significant variations compared to the case in which traditional BCs based on mass flow rate fractions was used and is in agreement with the in vivo data available in the literature.

Flow transport and gas mixing during invasive high frequency oscillatory ventilation.

A large Eddy simulation (LES) based computational fluid dynamics study was performed to investigate gas transport and mixing in patient specific human lung models during high frequency oscillatory ventilation. Different pressure-controlled waveforms (sinusoidal, exponential and square) and ventilator frequencies (15, 10 and 6Hz) were used (tidal volume=50mL). The waveforms were created by solving the equation of motion subjected to constant lung wall compliance and flow resistance.