BACKGROUND:Thoracic CO2 insufflation with positive intrathoracic pressure is usually effective during thoracoscopic surgery, however, lung collapse is sometimes insufficient. We hypothesized that inappropriate bronchial collapse might cause this unsuccessful lung collapse. OBJECTIVE:The objective of this study was to construct a computational mechanical model of bronchi for practical simulation to discover the optimal conditions of positive intrathoracic pressure during thoracoscopic surgery. METHODS:Micro-focus high-resolution X-ray computed tomography measurements of lungs from just-slaughtered swine were extracted, and the three-dimensional geometries of the bronchi under pressurized and depressurized conditions were measured accurately. The mechanical properties of the bronchus were also measured. Computational fluid dynamics (CFD) and computational structural mechanics (CSM) analyses were conducted. RESULTS:The CSM results indicated that the present structural model could simulate bronchial occlusion. The CFD results showed that airflows from pressed lung alveoli might cause low-internal-pressure regions when suddenly or heterogeneously pushed airflow was injected from a small branching bronchus to a large bronchus. A preliminary computational mechanical model of bronchi was constructed. CONCLUSIONS:We demonstrated the performance of the mechanical model of bronchi in rough simulations of bronchial occlusions. However, this model should be verified further using human data to facilitate its introduction to clinical use.

中文翻译：

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支气管计算力学模型的构建，用于实际模拟普通胸外科手术中最佳胸内正压条件

背景：胸腔镜手术中胸腔内正压CO2吹入通常有效，但有时肺塌陷不足。我们假设不适当的支气管塌陷可能导致这种不成功的肺塌陷。目的：本研究的目的是构建用于实际模拟的支气管计算力学模型，以发现胸腔镜手术中胸内正压的最佳条件。方法：提取刚屠宰猪肺的微焦点高分辨率X射线计算机断层扫描测量值，准确测量加压和减压条件下支气管的三维几何形状。还测量了支气管的机械性能。进行了计算流体动力学 (CFD) 和计算结构力学 (CSM) 分析。结果：CSM 结果表明，本结构模型可以模拟支气管闭塞。CFD 结果表明，当突然或不均匀地推动气流从小支支气管注入大支气管时，来自受压肺泡的气流可能会导致低内压区域。建立了支气管的初步计算力学模型。结论：我们证明了支气管机械模型在支气管闭塞的粗略模拟中的性能。但是，应该使用人类数据进一步验证该模型，以促进其引入临床使用。CSM 结果表明本结构模型可以模拟支气管闭塞。CFD 结果表明，当突然或不均匀地推动气流从小支支气管注入大支气管时，来自受压肺泡的气流可能会导致低内压区域。建立了支气管的初步计算力学模型。结论：我们证明了支气管机械模型在支气管闭塞的粗略模拟中的性能。但是，应该使用人类数据进一步验证该模型，以促进其引入临床使用。CSM 结果表明本结构模型可以模拟支气管闭塞。CFD 结果表明，当突然或不均匀地推动气流从小支支气管注入大支气管时，来自受压肺泡的气流可能会导致低内压区域。建立了支气管的初步计算力学模型。结论：我们证明了支气管机械模型在支气管闭塞的粗略模拟中的性能。但是，应该使用人类数据进一步验证该模型，以促进其引入临床使用。CFD 结果表明，当突然或不均匀地推动气流从小支支气管注入大支气管时，来自受压肺泡的气流可能会导致低内压区域。建立了支气管的初步计算力学模型。结论：我们证明了支气管机械模型在支气管闭塞的粗略模拟中的性能。但是，应该使用人类数据进一步验证该模型，以促进其引入临床使用。CFD 结果表明，当突然或不均匀地推动气流从小支支气管注入大支气管时，来自受压肺泡的气流可能会导致低内压区域。建立了支气管的初步计算力学模型。结论：我们证明了支气管机械模型在支气管闭塞的粗略模拟中的性能。但是，应该使用人类数据进一步验证该模型，以促进其引入临床使用。