To compare effect of high-frequency oscillation ventilation （HFOV） and conventional mandatory ventilation （CMV） on lung injury development in rabbit with acute respiratory distress syndrome （ ARDS）. Methods Anim...To compare effect of high-frequency oscillation ventilation （HFOV） and conventional mandatory ventilation （CMV） on lung injury development in rabbit with acute respiratory distress syndrome （ ARDS）. Methods Animals that underwent saline lung lavage to produce lung injury were randomized to one of the two treatment groups （ HFOV or CMV, n =6）. PaCO2 was maintained between 35 -45mmHg and arterial oxygen saturation （ SaO2 ） was maintain 〉 88% by adjusting corresponding ventilator parameters. Ventilation period was 6h. Lung fluids were aspirated before and at the end of ventilation for cell analysis. Then the animals were euthanized, lung tissue was removed for wet/dry weight measurement, light and electron microscopic examination. Besults The difference of artery blood gas analyses（pH, PaO2, PaCO2 ） between HFOV and CMV was insignificant. The difference between HFOV and CMV in cytological examination of lung fluids, wet/dry weight measurement was also insignificant. But compared with CMV, HFOV not only reduced the area of lung injury, but also reduced lung injury score in light and electron microscopic examination. Conclusion When same artery blood gas analysis was obtained, HFOV significantly reduced lung injury development in ARDS animal than CMV. As a lung protection strategy, HFOV can be used in the treatment of ARDS.展开更多
As an important life support treatment, mechanical ventilation is usually adopted in clinics. With the development of the res-piratory diagnostic and treatment technologies, air flow dynamics of mechanical ventilation...As an important life support treatment, mechanical ventilation is usually adopted in clinics. With the development of the res-piratory diagnostic and treatment technologies, air flow dynamics of mechanical ventilation is usually referenced in the evaluation of pulmonary status and assessment of respiratory therapy. In order to improve the ventilation efficiency and provide a reference for pulmonary diagnostics, in this paper, a new mathematical model of mechanical ventilation system was set up. Furthermore, a prototype mechanical ventilation system for an artificial simulating lung was designed and experimentally studied. Lastly, in order to improve the ventilation efficiency and provide a reference for pulmonary diagnostics, the air flow dynamics of the mechanical ventilation system was illustrated through simulation and experimental studies. The study can be helpful to the optimization of the mechanical ventilation system.展开更多
This paper presents a numerical study on the turbulent bubbly wakes created by the ventilated partial cavity.A semi-empirical approach is introduced to model the discrete interface of the ventilated cavity and its com...This paper presents a numerical study on the turbulent bubbly wakes created by the ventilated partial cavity.A semi-empirical approach is introduced to model the discrete interface of the ventilated cavity and its complex gas leakage rate induced by the local turbulent shear stress.Based on the Eulerian-Eulerian two-fluid modeling framework,a population balance approach based on MUltiple-SIze-Group (MUSIG) model is incorporated to simulate the size evolution of the sheared off microbubbles and its complex interactions with the two-phase flow structure in the wake region.Numerical predictions at various axial locations downstream of the test body were in satisfactory agreement with the experimental measurements.The captured bubbly wake structure illustrates that the bubbles may disperse as a twin-vortex tube driven by gravity effect.The predicted Sauter mean bubble diameter has confirmed the dominance of the coleascense process in the axial direction.As the bubbles develop downstream,the coleascense and breakup rate gradually reach balance,resulting in the stable bubble diameter.A close examination of the flow structures,gas void fraction distributions and the bubble size evolution provides valuable insights into the complex physical phenomenon induced by ventilated cavity.展开更多
文摘To compare effect of high-frequency oscillation ventilation （HFOV） and conventional mandatory ventilation （CMV） on lung injury development in rabbit with acute respiratory distress syndrome （ ARDS）. Methods Animals that underwent saline lung lavage to produce lung injury were randomized to one of the two treatment groups （ HFOV or CMV, n =6）. PaCO2 was maintained between 35 -45mmHg and arterial oxygen saturation （ SaO2 ） was maintain 〉 88% by adjusting corresponding ventilator parameters. Ventilation period was 6h. Lung fluids were aspirated before and at the end of ventilation for cell analysis. Then the animals were euthanized, lung tissue was removed for wet/dry weight measurement, light and electron microscopic examination. Besults The difference of artery blood gas analyses（pH, PaO2, PaCO2 ） between HFOV and CMV was insignificant. The difference between HFOV and CMV in cytological examination of lung fluids, wet/dry weight measurement was also insignificant. But compared with CMV, HFOV not only reduced the area of lung injury, but also reduced lung injury score in light and electron microscopic examination. Conclusion When same artery blood gas analysis was obtained, HFOV significantly reduced lung injury development in ARDS animal than CMV. As a lung protection strategy, HFOV can be used in the treatment of ARDS.
基金supported by the National Natural Science Foundation of China(Grant No.51575020)
文摘As an important life support treatment, mechanical ventilation is usually adopted in clinics. With the development of the res-piratory diagnostic and treatment technologies, air flow dynamics of mechanical ventilation is usually referenced in the evaluation of pulmonary status and assessment of respiratory therapy. In order to improve the ventilation efficiency and provide a reference for pulmonary diagnostics, in this paper, a new mathematical model of mechanical ventilation system was set up. Furthermore, a prototype mechanical ventilation system for an artificial simulating lung was designed and experimentally studied. Lastly, in order to improve the ventilation efficiency and provide a reference for pulmonary diagnostics, the air flow dynamics of the mechanical ventilation system was illustrated through simulation and experimental studies. The study can be helpful to the optimization of the mechanical ventilation system.
基金supported by the Chinese Council Scholarship (Grant No.2009611040)the Australian Research Council (Grant No.DP0877743)
文摘This paper presents a numerical study on the turbulent bubbly wakes created by the ventilated partial cavity.A semi-empirical approach is introduced to model the discrete interface of the ventilated cavity and its complex gas leakage rate induced by the local turbulent shear stress.Based on the Eulerian-Eulerian two-fluid modeling framework,a population balance approach based on MUltiple-SIze-Group (MUSIG) model is incorporated to simulate the size evolution of the sheared off microbubbles and its complex interactions with the two-phase flow structure in the wake region.Numerical predictions at various axial locations downstream of the test body were in satisfactory agreement with the experimental measurements.The captured bubbly wake structure illustrates that the bubbles may disperse as a twin-vortex tube driven by gravity effect.The predicted Sauter mean bubble diameter has confirmed the dominance of the coleascense process in the axial direction.As the bubbles develop downstream,the coleascense and breakup rate gradually reach balance,resulting in the stable bubble diameter.A close examination of the flow structures,gas void fraction distributions and the bubble size evolution provides valuable insights into the complex physical phenomenon induced by ventilated cavity.
