PULMONARY MASS AND HEAT TRANSPORT

肺传质和传热

• 批准号: 6182330
• 负责人: JAMES Bernard GROTBERG
• 金额: $ 20.07万
• 依托单位: UNIVERSITY OF MICHIGAN AT ANN ARBOR
• 依托单位国家: 美国
• 财政年份: 1988
• 资助国家: 美国
• 起止时间: 1988-08-01 至 2003-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6182330
• 关键词: biological fluid transport; computer simulation; fluid flow; laboratory rat; mathematical model; model design /development; nonblood rheology; pulmonary surfactants; respiratory airflow measurement; respiratory airway clearance; respiratory airway pressure; respiratory airway volume; respiratory gas transport; video microscopy

This proposal intends to study two aspects of pulmonary transport, one in the gas phase and one in the airway liquid phase, which are involved in respiratory therapeutic modalities. The distribution of transported material (gas, surfactant, drugs) in both depends upon the interaction of diffusive and convective processes as well as boundary conditions determined by common local lung structure and composition, while techniques to investigate both involve tracking the dispersion of an imposed gas or surfactant bolus or microbolus. Our major objective is to identify the important determinants of contaminant transport within the airstream (on the scale of the entire airway tree), and within the airway liquid lining/tissue (on the scale of spreading surfactant). Two important and different studies of transport are proposed which share many similarities both in detail and in approach. In the first project pulmonary gas transport during intra-tracheal insufflation (ITI), with or without external chest vibrations, will be studied to investigate ITI as a means of enhancing C02 removal and ventilatory efficiency in models of chronic ventilatory failure (e.g. spinal cord injury, neuromuscular disorders). The experimental technique underlying this transport study will be to follow the dispersion of a localized bolus of tracer-gas by intra-lumenal gas sampling, in animal and hardware models of ITI. This new technique will allow us to interpret a local D-eff from the concentration data measured at the point of injection, giving us the unique ability to examine regional and local differences in transport. Predictive models of this transport will be developed in tandem with the experimentation to provide a framework for interpreting data and guiding experimental parameter ranges. In the second project pulmonary liquid transport following the delivery of exogenous surfactants, either in aerosol droplets or large scale slugs which feed a surfactant monolayer, will be studied. This situation is found in surfactant replacement therapy for surfactant-deficient neonates or intra-airway drug delivery. The aim is to understand how far and how fast the surfactant (plus any dissolved species) is transported from where it impacts on the lining to its destination. The technique underlying this investigation will be the introduction of a localized surfactant bolus (microdroplet or slug) onto the air-liquid interface in animal and hardware models, while video-microscopy and laser interferometric methods will be used to track its dispersion along the interface and to investigate film rupture phenomena. In addition to measuring the spreading rates, use of our theoretical modelling will allow us to infer physical properties of the liquid lining (thickness, viscosity, surface tension) in airways and in alveoli. Theoretical modelling will provide a basis for interpreting the data and suggesting how to control the delivery.

该提案旨在研究肺部运输的两个方面， 一种在气相中，一种在气道液相中，它们是 参与呼吸治疗方式。 分布情况 两者中输送的物质（气体、表面活性剂、药物）取决于 以及扩散和对流过程的相互作用 由共同的局部肺结构决定的边界条件 和构图，而研究两者的技术都涉及 跟踪施加的气体或表面活性剂团的分散或 微丸。 我们的主要目标是确定重要的 气流内污染物输送的决定因素（在 整个气道树的规模），以及气道液体内 衬里/组织（按表面活性剂的扩散程度）。 二 提出了重要且不同的运输研究，其中 在细节和方法上都有许多相似之处。 在 第一个项目气管内肺部气体输送 充气（ITI），无论有或没有外部胸部振动，都会 研究 ITI 作为增强 CO2 去除的手段 慢性通气衰竭模型中的通气效率和通气效率 （例如脊髓损伤、神经肌肉疾病）。 这 这项运输研究的实验技术将是 跟踪示踪气体的局部团块的分散 ITI 的动物和硬件模型中的腔内气体采样。 这项新技术将使我们能够解释局部 D-eff 注射点测量的浓度数据，给出 我们具有检查区域和地方差异的独特能力 运输。 将开发这种运输的预测模型 与实验同时提供一个框架 解释数据并指导实验参数范围。 在 继“肺液体转运”项目之后的第二个项目 外源性表面活性剂的输送，无论是气溶胶液滴还是 供给表面活性剂单层的大尺度段塞，将 研究过。 这种情况出现在表面活性剂替代疗法中 用于表面活性剂缺乏的新生儿或气道内药物输送。 目的是了解表面活性剂作用的距离和速度（加上 任何溶解的物种）从其影响的地方运输 衬砌到目的地。 这背后的技术 研究将引入局部表面活性剂 丸剂（微滴或团块）到气液界面上 动物和硬件模型，而视频显微镜和激光 干涉测量方法将用于跟踪其沿着 界面并研究薄膜破裂现象。 在 除了测量铺展率之外，还使用我们的理论 建模将使我们能够推断液体的物理特性 气道和内壁的衬里（厚度、粘度、表面张力） 肺泡。 理论模型将为 解释数据并建议如何控制交付。