China
Africa
Explore chapters and articles related to this topic
Iatrogenic tracheobronchial and chest injury
Published in Philippe Camus, Edward C Rosenow, Drug-induced and Iatrogenic Respiratory Disease, 2010
Marios Froudarakis, Demosthenes Makris, Demosthenes Bouros
Iatrogenic haemothorax is defined as accumulation of pleural fluid with an haematocrit at least 50 per cent that of peripheral blood, secondary to a medical or surgical procedure. The incidence of iatrogenic haemothorax is lower than that of iatrogenic pneumothorax but it is difficult to estimate precisely since these events are not registered systematically. Most common causes are thoracic surgery, placement of chest tubes or central venous catheters, thoracocentesis, and transthoracic or transbronchial biopsies.67 Sources of bleeding include the thoracic cage, lungs, the diaphragm, blood vessels and mediastinum. Significant bleeding occurs when the intercostal arteries or the internal mammary artery are damaged. Although rarely, anticoagulation (heparin, aspirin, ticlopidine) should be also considered as a potential cause of haemothorax including those massive in size, usually occurring within the first week of therapy for thromboembolism.67 Anticoagulation can be associated with life-threatening haemothorax which complicates chest tube placement.
Elements of Continuum Mechanics
Published in Clement Kleinstreuer, Biofluid Dynamics, 2016
In addition to the upper airways and lungs, the respiratory system also assures for proper breathing in the thorax (or chest) and the abdomen, where the two are separated by a diaphragm. Neural inputs to and feedback from these pulmonary structures are controlled by the nervous system. Specifically, on inspiration the respiratory muscles and chest wall, together with the downward moving diaphragm act like a “pump” creating a negative-pressure field (i.e., a partial vacuum) by enlarging the thoracic space. On expiration, the respiratory muscles relax, the diaphragm moves from its flat position upwards again, and the lung deflates (Pedley, 1977). The rate and depth of ventilation, i.e., air movement in and out of the respiratory tract, is neurologically controlled to maintain the required CO2/O2-levels and, in conjunction with the kidneys, a normal body fluid pH of 7.4. In addition to ventilation and subsequent gas diffusion in the alveolar region, blood perfusion via the bronchial and pulmonary circulation supplies nutrients and oxygen to the lungs. Specifically, the bronchial arteries, branching from the thoracic aorta and intercostal arteries, perfuse the trachea and bronchi as well as the lungs, tissue, nerves, and outer layers of the pulmonary arteries and veins. The pulmonary circulation is a low-pressure system where venous blood is transported from the right ventricle to the right and left lungs (see Fig.1.1.2 and Sect.2.2). In the pulmonary capillary bed the gas exchange takes place and then O2-rich blood is returned through the pulmonary veins to the left atrium.
Numerical study on the injury mechanism of blunt aortic rupture of the occupant in frontal and side-impact
Published in International Journal of Crashworthiness, 2023
Fang Tong, FengChong Lan, JiQing Chen, DongRi Li, Xiong Li
The occupant FE model used in the current study was the 50 percentile Chinese male model established previously based on computerized tomography data [26–31]. The model consists of the head, neck, torso, and limbs as shown in Figure 1. The assembled human model and each part of it were all validated by PMHS tests from published literature [32–35], including frontal thorax impact, lateral thorax impact, head impact, bone bending tests, etc. In the thoracic cavity, the heart is connected with the lungs by the pulmonary artery. The descending aorta was constrained with the spine to simulate the action of the intercostal arteries. The low region of the heart and the distal end of the descending aorta were also constrained to represent the contact with the diaphragm. The whole model contained 1 734 889 elements and 1 006 365 nodes, respectively. In the human model, the property of the skeleton was defined as elastoplastic, and the ultimate strain was set to simulate the rib fracture. Organs like the heart and lungs were represented by viscoelastic materials. Vessels like pulmonary artery, pulmonary vein, and superior vena cava were set as linear elastic to improve the computational efficiency. For more detailed material properties of the human FE model, see the previous studies [26–31].
Fluid–structure interaction simulation of aortic blood flow by ventricular beating: a preliminary model for blunt aortic injuries in vehicle crashes
Published in International Journal of Crashworthiness, 2020
Wei Wei, Cyril J.F. Kahn, Michel Behr
The validated heart-aorta model was integrated with the global human body models consortium (GHMBC) M50 model (V4.4; Elemance, Winston-Salem, USA). The GHBMC model has been widely validated against various impact scenarios and for different body parts [26]. The heart and aorta of GHBMC were simplified while blood flow could not be simulated. The original GHBMC heart-aorta was replaced with current FSI heart-aorta model (displayed in Figure 2A). Superior arteries of the aorta were elongated to attach to the clavicles by sharing common nodes. The descending aorta was connected to the GHBMC abdominal descending aorta by sharing common nodes. Surface-to-surface contacts were defined between the heart-aorta and the surrounding GHBMC components (i.e. lung, diaphragm, and spine). Tied contact was defined between the pulmonary arteries and the lung root to attach both components. Tied contacts were defined between the descending aorta and spine to model the subcostal artery and eight intercostal arteries (corresponding to the boundary constraints in Figure 1A).