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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
Symptoms in tracheal stenosis include dyspnoea in 80 per cent of cases, cough in 45 per cent, wheezing, and stridor. Haemoptysis may be associated to cough in less than 10 per cent of the cases.18 Diagnosis may be confused with asthma. The history of recent endotracheal and/or endobronchial intervention together with the characteristic pattern of flow/volume curve will support the diagnosis, which is confirmed by fibre-optic bronchoscopy. Fibre-optic bronchoscopy will report the length of the stenosis, its distance from the vocal cords and carina, and its form.19 This information is important for accurate treatment.
Scaffolds for tracheal regeneration
Published in Gilson Khang, Handbook of Intelligent Scaffolds for Tissue Engineering and Regenerative Medicine, 2017
Doh Young Lee, Seong Keun Kwon
There are more than 40 conditions that affect the airway and impact a person’s ability to breathe. The airway can be damaged due to stenosis, infection, cancer, congenital anomalies, trauma, and foreign-body aspiration. Tracheal stenosis, a condition in which the windpipe narrows, affects 4%–13% of adults and 1%–8% of neonates. It is classified on the basis of the onset of stenosis (congenital—from birth; acquired—develops later in life).
Design of 4D printed shape-changing tracheal stent and remote controlling actuation
Published in International Journal of Smart and Nano Materials, 2021
Fenghua Zhang, Nan Wen, Linlin Wang, Yunqi Bai, Jinsong Leng
The trachea can keep the respiratory tract unobstructed [32], but the trachea is very fragile and vulnerable to various diseases [33–35]. As a common critical disease, airway stenosis is the main airway restriction caused by airway obstruction, which can cause dyspnea and even endanger the life of patients. However, due to the fragility and special structure of the trachea, it is difficult to repair the injured trachea [36–39]. Till now, endotracheal stent intervention is the most common and effective treatment of tracheal stenosis. In this process, the stent is implanted into the narrow trachea to reshape the diameter of the trachea, quickly relieve the airway stenosis and relieve the symptoms of dyspnea. NiTi shape memory alloy tracheal stent are commonly used in clinic. The main disadvantages of NiTi stents are difficult reduction, easy to cause tracheal obstruction if collapse occurs. In addition, it is difficult to remove after implantation. Moreover, tumor or granulation growth is easy to pass through the mesh. In view of the shortcomings of the above shape memory alloy tracheal stent, the shape memory PLA composite tracheal stent was designed with SMP as material, and the collapse of the stent was repaired with SMP of the stent. The degradability of SMP makes it unnecessary to remove the stent. Combined with 4D printing, the shape memory tracheal stent with complex and optimized structure can be customized.
Evaluating the biomechanical characteristics of cuffed-tracheostomy tubes using finite element analysis
Published in Computer Methods in Biomechanics and Biomedical Engineering, 2021
Dhananjay Radhakrishnan Subramaniam, Liran Oren, J. Paul Willging, Ephraim J. Gutmark
While our previously published study described the cuff inflation for a rigid airway (Subramaniam et al. 2019), the present study included the mechanical properties of soft and cartilaginous trachea tissue, which improved the accuracy of the cuff-airway interaction. Besides, the in-vivo profile of the cuff could possibly influence the airflow velocity and wall shear stress distribution during natural and ventilator-assisted breathing, as outlined in our aforementioned CFD study. The results from our CFD study and the FE analysis described in the present study indicate that while some tube designs have favourable flow characteristics, the biomechanical characteristics are less desirable. For instance, the CFD study showed that the Portex tube generated lower wall shear stresses (WSS) at the carina, whereas the FE analysis indicated high von Mises stresses in the cartilage rings and smooth muscle. In contrast, the Shiley tubes were characterized by lower mechanical stresses and higher WSS at the same locations. This emphasizes the importance of designing an ideal tracheostomy tube, which combines the flow features of curved tubes (i.e., Portex and Tracoe) and biomechanical features of angled tubes (i.e., Shiley). Tracheal stenosis is a potential post-surgical complication of tracheostomy, which could possibly occur at the cuff-airway interface as a result of the pressure forces exerted by the cuff on the posterior-wall mucosa (Epstein 2005). While the high-volume, low-pressure cuffs analyzed in our study exert lower pressure forces on the airway wall, when compared to low-volume, high-pressure cuffs, over-inflation of the cuff could possibly exceed the capillary pressure and subsequently cause ischemic injury. Although the magnitude and distribution of von Mises stresses in the smooth muscle resulting from the cuff inflation were lower than the experimentally evaluated tensile strength (Trabelsi et al. 2010), the model-predicted stresses could be used to develop injury criteria for different cuff designs, similar to other computational studies (Cotton et al. 2016), which could potentially assist clinicians in selecting a suitable cuff design that minimizes the probability of airway injury. Conversely, for a selected cuff design, the proposed FE model could assist in optimizing the cuff pressure that reduces the mechanical stresses while retaining the sealing efficacy and subsequently minimizes the probability of over inflation of the cuff. Additionally, the signed distance between the cuff and the airway wall (Figure 5), which represents the difference between the cuff and tracheal diameters, could be used by clinicians to identify and correct air leaks and subsequently minimize the possibility of life-threatening ventilatory failure (El-Orbany and Salem 2013). Furthermore, our FE model could potentially minimize the need for extensive instrumentation and the time required to evaluate the biomechanical responses using experimental models of cuff sealing.