title: Flow transport and gas mixing during invasive high frequency oscillatory ventilation.
abstract: 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. Simulations were conducted with and without endotracheal tube to understand the effect of invasive management device. Variation of pressure-controlled waveform and frequency exhibits significant differences on counter flow pattern, which could lead to a significant impact on the gas mixing efficiency. Pendelluft-like flow was present for the sinusoidal waveform at all frequencies but occurred only at early inspiration for the square waveform at highest frequency. The square waveform was most efficient for gas mixing, resulting in the least wall shear stress on the lung epithelium layer thereby reducing the risk of barotrauma to both airways and the alveoli for patients undergoing therapy.
authors.affiliation: Department of Mechanical Engineering & Mechanics, Lehigh University, Bethlehem, PA 18015, United States.
authors.forename: Mohammed
authors.initials: M
authors.lastname: Alzahrany
authors.affiliation: Department of Mechanical Engineering & Mechanics, Lehigh University, Bethlehem, PA 18015, United States. Electronic address: arb612@Lehigh.edu.
authors.forename: Arindam
authors.initials: A
authors.lastname: Banerjee
authors.affiliation: Respiratory and Critical Care Medicine, University of Missouri-Kansas City School of Medicine, Kansas City, MO 64108, United States.
authors.forename: Gary
authors.initials: G
authors.lastname: Salzman
mesh_terms: D000465:Algorithms; D003198:Computer Simulation; D045853:Exhalation / Q000502:physiology; D005260:Female; D006612:High-Frequency Ventilation / Q000295:instrumentation / Q000379:methods; D006801:Humans; D057446:Hydrodynamics; D021621:Imaging, Three-Dimensional; D001239:Inhalation / Q000502:physiology; D007442:Intubation, Intratracheal; D008168:Lung / Q000000981:diagnostic imaging / Q000502:physiology; D008875:Middle Aged; D008954:Models, Biological; D009038:Motion; D011312:Pressure; D011659:Pulmonary Gas Exchange; D012123:Pulmonary Ventilation / Q000502:physiology; D014057:Tomography, X-Ray Computed
keywords: Endotracheal tube; High frequency oscillatory ventilation; Pulmonary flow