Department of Biomedical Engineering, Science and Research Branch, Islamic Azad University, Tehran, Iran.
Department of Biomedical Engineering, Science and Research Branch, Islamic Azad University, Tehran, Iran.
Comput Methods Programs Biomed. 2019 Aug;177:203-209. doi: 10.1016/j.cmpb.2019.05.031. Epub 2019 May 30.
Sneezing is one of the most critical conditions that can occur in the human upper airway. As some reports confirm the injury to the human upper respiratory airway while sneezing. Therefore, the accurate study of the distribution of pressure and velocity in this case is of great importance.
In the present study, using a real human upper airway model, the pressure and velocity of the airflow generated in the tract during the sneezing have been investigated. Also, considering the results from a spirometer device as a boundary condition in the simulation process, the calculations have become reliable.
According to the results, during sneezing, taking into account that the average outlet flow rate from the mouth is 4.79 L/s, the velocity of outlet airflow from the mouth and nose reaches 5.3 and 8.4 m/s, respectively. These values were 11.5 and 19, respectively, when the desired maximum flow rate was 10.58 L/s. It can be concluded that the increasing of trachea flow rate, leads to higher percentage of the outlet flow rate from the nose . The highest average pressure and velocity have been occurred in the trachea. Among other salient results of this report, increased average static pressure of larynx to approximately 10 kPa can be pointed which indicates that this area is critical so that the thyroid cartilage defect is likely to occur. It is also noteworthy that the increase of speed at nasopharynx is up to 125 m/s so that the cross-section changing in this area leads the fluid acts as a jet flow. Due to the specific geometry of the nasal cavity, some streams similar to poor shocks are formed, these shocks get stronger by increasing of the flow rate. The thyroid cartilage and nasal cavity are exposed to maximum static pressure extremums, respectively.
We introduced a model simulating a normal sneezing for two cases using a healthy 30-year-old male person. We believe that the model should be applied for different persons and an atlas of data could be obtained from different cases. This may help the medical system to have more data about the sneezing process.
打喷嚏是人类上呼吸道最关键的情况之一。因为一些报告证实打喷嚏会对上呼吸道造成损伤。因此，准确研究这种情况下压力和速度的分布非常重要。
在本研究中，使用真实的人类上呼吸道模型，研究了打喷嚏时呼吸道中气流的压力和速度。同时，考虑到呼吸计设备的结果作为模拟过程中的边界条件，计算结果更加可靠。
根据结果，在打喷嚏时，考虑到从口腔平均出口流速为 4.79 L/s，口腔和鼻腔的出口气流速度分别达到 5.3 和 8.4 m/s，当所需的最大流速为 10.58 L/s 时，这两个速度分别为 11.5 和 19。可以得出结论，气管流速的增加导致从鼻腔流出的出口气流比例更高。最高平均压力和速度出现在气管中。本报告的其他突出结果包括，喉的平均静压力增加到约 10 kPa，可以指出该区域非常关键，因此甲状腺软骨缺陷很可能发生。同样值得注意的是，鼻咽速度增加到 125 m/s，使得该区域的横截面变化导致流体表现为射流。由于鼻腔的特殊几何形状，形成了一些类似于不良冲击波的流，随着流速的增加，这些冲击波会变得更强。甲状腺软骨和鼻腔分别承受最大静态压力极值。
我们介绍了一种模拟正常打喷嚏的模型，针对两种情况使用了一名健康的 30 岁男性。我们相信该模型可以应用于不同的人，并从不同的病例中获得数据图谱。这可能有助于医疗系统获得更多关于打喷嚏过程的数据。
