Goal: Alveolar compliance is a main determinant of lung airflow. The compliance of the alveoli is a function of their tissue fiber elasticity, fiber volume, and surface tension. The compliance varies during respiration because of the nonlinear nature of fiber elasticity and the time-varying surface tension coating the alveoli. Respiratory conditions, like acute respiratory distress syndrome (ARDS) and idiopathic pulmonary fibrosis (IPF) affect fiber elasticity, fiber volume and surface tension. In this paper, we study the alveolar tissue fibers and surface tension effects on lung mechanics. Methods: To better understand the lungs, we developed a physiology-based mathematical model to 1) describe the effect of tissue fiber elasticity, fiber volume and surface tension on alveolar compliance, and 2) the effect of time-varying alveolar compliance on lung mechanics for healthy, ARDS and IPF conditions. Results: We first present the model sensitivity analysis to show the effects of model parameters on the lung mechanics variables. Then, we perform model simulation and validate on healthy non-ventilated subjects and ventilated ARDS or IPF patients. Finally, we assess the robustness and stability of this dynamic system. Conclusions: We developed a mathematical model of the lung mechanics comprising alveolar tissue and surfactant properties that generates reasonable lung pressures and volumes compared to healthy, ARDS, and IPF patient data.

中文翻译：

---

肺泡组织纤维和表面活性剂对肺力学的影响——ARDS 和 IPF 患者的模型开发和验证

目标：肺泡顺应性是肺气流的主要决定因素。肺泡的顺应性是其组织纤维弹性、纤维体积和表面张力的函数。由于纤维弹性的非线性性质和覆盖肺泡的随时间变化的表面张力，在呼吸过程中顺应性会发生变化。呼吸系统疾病，如急性呼吸窘迫综合征 (ARDS) 和特发性肺纤维化 (IPF) 会影响纤维弹性、纤维体积和表面张力。在本文中，我们研究了肺泡组织纤维和表面张力对肺力学的影响。方法：为了更好地了解肺部，我们开发了一个基于生理学的数学模型，以 1) 描述组织纤维弹性、纤维体积和表面张力对肺泡顺应性的影响，以及 2) 时变肺泡顺应性对健康肺力学的影响, ARDS 和 IPF 条件。结果：我们首先提出模型敏感性分析，以显示模型参数对肺力学变量的影响。然后，我们对健康的非通气受试者和通气的 ARDS 或 IPF 患者进行模型模拟和验证。最后，我们评估了这个动态系统的鲁棒性和稳定性。结论：我们开发了一个包含肺泡组织和表面活性剂特性的肺力学数学模型，与健康、ARDS 和 IPF 患者数据相比，该模型可产生合理的肺压和肺容量。