scholarly journals Structural and functional alterations of the tracheobronchial tree after left upper pulmonary lobectomy for lung cancer

2019 ◽  
Vol 18 (1) ◽  
Author(s):  
Qingtao Gu ◽  
Shouliang Qi ◽  
Yong Yue ◽  
Jing Shen ◽  
Baihua Zhang ◽  
...  
Keyword(s):  
Flow Rate ◽  
Main Bronchus ◽  
Tracheobronchial Tree ◽  
Sectional Area ◽  
Pulmonary Lobectomy ◽  
Airflow Velocity ◽  
Cross Sectional ◽  
Lobar Bronchus ◽  
Cfd Method ◽  
The Right

Abstract Background Pulmonary lobectomy has been a well-established curative treatment method for localized lung cancer. After left upper pulmonary lobectomy, the upward displacement of remaining lower lobe causes the distortion or kink of bronchus, which is associated with intractable cough and breathless. However, the quantitative study on structural and functional alterations of the tracheobronchial tree after lobectomy has not been reported. We sought to investigate these alterations using CT imaging analysis and computational fluid dynamics (CFD) method. Methods Both preoperative and postoperative CT images of 18 patients who underwent left upper pulmonary lobectomy are collected. After the tracheobronchial tree models are extracted, the angles between trachea and bronchi, the surface area and volume of the tree, and the cross-sectional area of left lower lobar bronchus are investigated. CFD method is further used to describe the airflow characteristics by the wall pressure, airflow velocity, lobar flow rate, etc. Results It is found that the angle between the trachea and the right main bronchus increases after operation, but the angle with the left main bronchus decreases. No significant alteration is observed for the surface area or volume of the tree between pre-operation and post-operation. After left upper pulmonary lobectomy, the cross-sectional area of left lower lobar bronchus is reduced for most of the patients (15/18) by 15–75%, especially for 4 patients by more than 50%. The wall pressure, airflow velocity and pressure drop significantly increase after the operation. The flow rate to the right lung increases significantly by 2–30% (but there is no significant difference between each lobe), and the flow rate to the left lung drops accordingly. Many vortices are found in various places with severe distortions. Conclusions The favorable and unfavorable adaptive alterations of tracheobronchial tree will occur after left upper pulmonary lobectomy, and these alterations can be clarified through CT imaging and CFD analysis. The severe distortions at left lower lobar bronchus might exacerbate postoperative shortness of breath.

scholarly journals Sonographic Measurement of Cross-sectional Area of the Median Nerve in Academic Dentists Without Symptoms or Signs of Carpal Tunnel Syndrome

2018 ◽  
Vol 35 (2) ◽  
pp. 105-111
Author(s):  
Akram Asbeutah ◽  
Mohsen Dashti ◽  
Abdullah AlMajran ◽  
Aref Ghayyath
Keyword(s):  
Median Nerve ◽  
Statistical Significance ◽  
Working Hours ◽  
Cross Sectional Area ◽  
Dominant Hand ◽  
Sectional Area ◽  
Cross Sectional ◽  
Increased Risk ◽  
Bone Level ◽  
The Right

The objective was to evaluate the distribution of the cross-sectional area (CSA) and flattening ratio (FR) of the median nerve (MN) in asymptomatic academic dentists using ultrasonography (US). Fifty academic dentists underwent US of the MN in transverse section at the pisiform bone level and the CSA (mm2) and FR were measured bilaterally. A CSA of <10 mm2 was considered normal. Paired t-test showed no statistical significance between either hand for CSA and FR ( P> .05). Two independent t-tests showed significant statistical differences ( P= .023) between males and females in the right dominant hand for CSA. Linear correlation analysis showed no significant correlation between CSA and FR for number of years of experience or number of working hours per day in either hand ( P>.05). The CSA was abnormal in the right dominant hand in 20 (40%) of the subjects. These male academic dentists were at increased risk of having an enlarged MN without symptoms.

scholarly journals Broken metallic tracheostomy tube migrating into the tracheobronchial tree

2016 ◽  
Vol 6 (1) ◽  
Author(s):  
Nilam U. Sathe ◽  
Ratna Priya ◽  
Sheetal Shelke ◽  
Kartik Krishnan
Keyword(s):  
Foreign Body ◽  
Tracheostomy Tube ◽  
Main Bronchus ◽  
Tracheobronchial Tree ◽  
Life Saving ◽  
Wear And Tear ◽  
Life Threatening ◽  
History Of ◽  
The Right ◽  
Periodic Replacement

Foreign body aspiration can be a life-threatening emergency. Broken tracheostomy tube in tracheobronchial tree is one of the rarest types of foreign body reported. Here we report two cases of fracture of metallic tracheostomy tube, leading to foreign body in tracheobronchial tree. A 14-year-old girl presented to our Emergency Department with history of respiratory distress and violent bouts of cough since 2 days. Chest X-ray showed that the broken part of the tube was lodged in the right main bronchus. The presence of Parkinson’s disease in the patient and restricted neck flexion offered a challenge both for the anaesthetist and the surgeon. We were successful in removing the broken tube in 13 small pieces. Check bronchoscopy was clear and the procedure went uneventful. We would like to conclude that broken tracheostomy tube presenting as foreign body bronchus is infrequent but it is a preventable complication of tarcheostomy. The patient must be kept on regular follow up to check for signs of wear and tear. Timely and periodic replacement of tracehostomy tube should also be done, otherwise such life-saving surgery can become lifethreatening.

Accuracy and precision of MR velocity mapping in measurement of stenotic cross-sectional area, flow rate, and pressure gradient

1993 ◽  
Vol 3 (2) ◽  
pp. 433-437 ◽  
Author(s):  
Lars Søndergaard ◽  
Freddy Ståhlberg ◽  
Carsten Thomsen ◽  
Anders Stensgaard ◽  
Knud Lindvig ◽  
...  
Keyword(s):  
Pressure Gradient ◽  
Flow Rate ◽  
Cross Sectional Area ◽  
Sectional Area ◽  
Velocity Mapping ◽  
Cross Sectional ◽  
Accuracy And Precision

scholarly journals Influence of malformation of right coronary artery originating from the left sinus on the hemodynamic environment

2020 ◽  
Author(s):  
Mengyang Cong ◽  
Xingming Xu ◽  
Jianfeng Qiu ◽  
Shun Dai ◽  
Chuanzhi Chen ◽  
...  
Keyword(s):  
Coronary Artery ◽  
Coronary Arteries ◽  
Right Coronary Artery ◽  
Clinical Symptoms ◽  
Element Model ◽  
Cross Sectional Area ◽  
Sectional Area ◽  
Cross Sectional ◽  
The Cross ◽  
The Right

Abstract Background: The Anomalous origin of the Right Coronary Artery (RCA) from the Left Coronary artery sinus(AORL) is one of the abnormal origins of the coronary arteries. Most of these issues seldom have effects on human health, but some individuals may have symptoms such as myocardial ischaemia or even sudden death. Recently, researchers are studying AORL through clinical cases, but study based on computational fluid dynamics (CFD) is rarely seen. In this study, haemodynamic changes between normal origin of the RCA and AORL are compared according to numerical simulation results.Methods: Realistic three-dimensional models of 16 normal right coronary arteries and 26 abnormal origins of the right coronary arteries were reconstructed, respectively. The blood flow was numerically simulated using software ANSYS. This study involves one-way fluid-solid coupling finite element model in which the blood is assumed to be incompressible Newtonian fluid, and the vessel is assumed to be isotropic, linear elastic material.Results: The differences of the cross-sectional area at the inlet between the normal group and the abnormal group was significant ( P <0.0001). There were significant differences in the volumetric flow ( P <0.0001) and the pressure ( P =0.0001). There were positive correlations with the ratio of the cross-sectional area of the RCA to the inlet area of the ascending aorta (AAO) and the ratio of the inlet volumetric flow of the RCA to the volumetric flow of the AAO, in both the normal ( P =0.0001, r=0.8198) and abnormal ( P =0.0199, r=0.4925) group.Conclusion: This study shows that the cross-sectional area of the inlet of AORL may cause ischaemia symptoms, and the results may contribute to the further understanding of the clinical symptoms of AORL based on the haemodynamics.

scholarly journals EFFECT OF OPERATING PARAMETERS UPON PERFORMANCE OF FUNCTIONAL SPECIMENS OF HIGH EXPANSION FOAM GENERATORS

2020 ◽  
Vol 1 (2) ◽  
pp. 14-21
Author(s):  
V Chuian ◽  
O Тymoshenko ◽  
A Hrachov
Keyword(s):  
Flow Rate ◽  
Cross Sectional Area ◽  
Solution Flow Rate ◽  
Operating Parameters ◽  
Spray Nozzle ◽  
Sectional Area ◽  
Solution Flow ◽  
Cross Sectional ◽  
Foam Expansion ◽  
Expansion Foam

The issues related to application of high expansion foam as flooding fire extinguishing agent as well as necessity of the development of high expansion foam generators in Ukraine are considered. Patent search concerning appropriate devices for generation of high expansion foam from foam solutions was conducted and it showed specific features of the components when generating high expansion foam. The results of the research of operating parameters of prototypes of high expansion foam generators of fan and ejection types are presented. For high expansion foam generators of fan type dependence of foam expansion, foam solution flow rate and amount of spent foam solution on the performance of the spray nozzle at different pressures and ratio of fan performance to the spray nozzle performance was established; the ratio of the cross-sectional area of the fan to the total area of the perforated holes in the foaming grid was studied, too. For high-expansion foam generators of the ejection type dependence of foam expansion, foam solution flow rate and amount of spent foam solution on the capacity of the spray nozzle unit at different pressures, foam solution flow rate to the total area of the holes in the foaming grid, and ratio of the cross-sectional area of the generator to the total area of the perforated holes of the foaming grid were studied. Functional models of the mentioned types of generators (both ejection (aspiration) one and generator equipped with fan (air blowing unit)) were developed, created and tested for the purpose of derivation of appropriate relations between their conditions of use and performance. At the same time, high expansion foam generators of fan type by their weight and size parameters are intended for use in the divisions of the Operative and Rescue Service of Civil Protection of the State Emergency Service of Ukraine as portable firefighting units. Such firefighting units are intended to be installed first of all on any state-of-the-art municipal fire engines equipped with autonomous AC generators. High expansion foam generators of ejection type are intended for use as firefighting units in foam firefighting systems of various facilities with fire hazard.

scholarly journals Analysis of Liquid Flow and Mixing in an Oscillatory Flow Reactor Provided with 2D Smooth Periodic Constrictions

2018 ◽  
Vol 4 (2) ◽  
pp. 1-15 ◽  
Author(s):  
F. Almeida ◽  
F. Rocha ◽  
A. Ferreira
Keyword(s):  
Flow Rate ◽  
Oscillatory Flow ◽  
Flow Reactor ◽  
Cross Sectional Area ◽  
Axial Dispersion ◽  
Mixing Efficiency ◽  
Sectional Area ◽  
Cross Sectional ◽  
Liquid Dispersion ◽  
Fluid Oscillation

In this research paper the residence time distribution (RTD) was monitored for a range of fluid oscillation, frequency, amplitude and flow rate in two oscillatory flow reactors (OFR) provided with 2D smooth periodic constrictions (2D-SPC) with different designs. It was studied the axial liquid dispersion using axial dispersion model and the mixing efficiency using tank-in-series model for continuous mode. Two cases, with and without fluid oscillation, were studied and determined the optimum conditions to ensure a close plug flow, an efficient mixing and a low axial liquid dispersion. The optimum operation conditions for the two 2D-SPC designs were found. Moreover, the effect of open cross-sectional area (a) on mixing and axial dispersion was also investigated. For low cross-sectional area values the mixing is higher. It was observed that fluid oscillation increases the mixing intensity even at lower flow rates, and the axial dispersion increases as the flow rate increases.

scholarly journals Analysis of Flame Propagation in Small Adiabatic Tubes Characterized by Different Degrees of the End Opening

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Artur N. Gutkowski ◽  
Zbigniew Cebulski
Keyword(s):  
Thermal Expansion ◽  
Pressure Gradient ◽  
Flame Propagation ◽  
Propagation Speed ◽  
Flame Speed ◽  
Exponential Dependence ◽  
Sectional Area ◽  
Cross Sectional ◽  
Frictional Forces ◽  
The Right

Abstract In the present work, we study numerically freely propagating flame in the stoichiometric propane-air mixture. The adiabatic small tubes with one end fully open and the second one characterized by different degrees of opening are examined. The degree of opening of the tubes was equal to: 0% (completely closed), 25%, 50%, 75% and 100% (fully opened) of the tube cross-sectional area. Several mechanisms, such as thermal expansion of the burned gas that can leave the tube freely (fully opened left end of the tube), frictional forces and movement of the unburned mixture generated by a pressure gradient, occur simultaneously during flame propagation. As a result, a nearly-exponential dependence of flame propagation speed as a function of time is observed. For fully open right end (100%), normalized flame speed reaches about 75–80 at the end of the tubes. By partially closing the right end, this effect is delayed and reduced – for 25% of the opening normalized flame speed is about 20 for all tube diameters.

scholarly journals Novel body positioning maximizes femoral venous size in adults: An ultrasonographic evaluation

2018 ◽  
Vol 25 (6) ◽  
pp. 338-342
Author(s):  
Hong Joon Ahn ◽  
Jun Wan Lee ◽  
Seung Woo Yoo ◽  
Jee Hyun Kim ◽  
Kun Dong Kim ◽  
...  
Keyword(s):  
Body Position ◽  
Femoral Vein ◽  
Cross Sectional Area ◽  
Sectional Area ◽  
Cross Sectional ◽  
Vein Diameter ◽  
The Mean ◽  
The Right ◽  
Ultrasound Scanner ◽  
Leg Position

Introduction: Increased femoral vein size may lead to a higher first pass success rate during central venous cannulation. The aim of this study was to evaluate the effects of body position on femoral vein anatomy for cannulation. Methods: This prospective study examined the femoral vein of healthy volunteers by ultrasound scanner. The changes in cross-sectional area and diameter of the femoral vein were evaluated. Right-sided measurements were taken at four different leg positions: neutral, frog leg, back-up, and back-up/frog leg position. Results: A total of 50 subjects were enrolled in the study. The mean femoral vein cross-sectional area were 0.57 ± 0.29 cm2, 0.90 ± 0.26 cm2, 1.05 ± 0.33 cm2, and 1.47 ± 0.34 cm2, and the mean femoral vein diameter were 0.75 ± 0.20 cm, 1.05 ± 0.28 cm, 1.25 ± 0.21 cm, and 1.46 ± 0.25 cm in order of neutral, back-up, frog leg, and back-up/frog leg position (p < 0.001). Conclusion: Performing the right femoral vein catheterization in back-up and frog leg position is associated with a greater cross-sectional area of the femoral vein.

scholarly journals Phenomenological modeling of diesel spray with varying injection profile

2018 ◽  
Vol 233 (11) ◽  
pp. 2780-2790 ◽  
Author(s):  
Long Liu ◽  
Yan Peng ◽  
Xiuzhen Ma ◽  
Naoto Horibe ◽  
Takuji Ishiyama
Keyword(s):  
Mass Flow Rate ◽  
Flow Rate ◽  
Momentum Flux ◽  
Combustion Process ◽  
Injection Rate ◽  
Diesel Spray ◽  
Sectional Area ◽  
Cross Sectional ◽  
Spray Penetration ◽  
Fuel Mass

Accurate and quick prediction of spray characteristics such as spray penetration is paramount for the understanding and quantitative analysis of the combustion process in diesel engines, in order to perform parametric study on advanced combustion process in diesel engines, zero-dimensional diesel spray model is often used for the prediction of the spray evolution. In this study, a previous zero-dimensional diesel spray model applied for the spray penetration prediction including the part after the end of injection with a constant injection rate was extended to the cases with varying injection rate. The effective injection velocity was introduced into the previous spray model, which is defined as the ratio of the momentum flux and fuel mass flow rate over the spray tip cross-sectional area. Combined with this definition, the analysis of effective injection rate and its response time was performed during and after the end of injection. After that, the fuel mass flow rate and momentum flux over the spray tip cross-sectional area were derived for varying injection rate even after the end of injection based on the momentum and fuel mass conservation along the spray axis, and further the spray penetration. Finally, the developed model was validated by comparing with the experimental data.

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