REGIONAL VENTILATION IN THE NON-HOMOGENEOUS LUNG

这个研究项目涉及区域分布的研究 在非均匀肺中的肺通气。 是 旨在检验呼吸频率和 潮气量应影响肺泡的区域分布 不同的通风方式取决于状态 软组织和气道。 本研究的目的是研究 活体犬，呼吸频率和潮气量的影响， 平均肺容量和区域间混合，在区域上 在三种不同的条件下， 非均匀性肺机制：1）大气道阻塞 通过支气管镜插入已知的横截面 口面积; 2）单侧支气管收缩 气雾剂中的组胺，以及3）由 肺灌洗。 肺泡通气将通过测量局部 放射性氮从肺气隙的周转率- 13在使用2D正电子照相机进行冲洗操作期间，或 固定正电子发射环形断层摄影机。 这 独特的环形摄像机创建三维重建的 具有出色空间分辨率的肺部。 区域分布 天然气运输创建了几个设置的传统和 高频小潮气量机械通气将 测定了 同时，区域力学特征 和振荡流率将被测量或估计，使用 结合新开发的气道内呼吸速度描记器， 正电子照相机和计算机模型的新技术 肺力学的一部分 理论模型结合了 肺的机械和气体运输特性， 区域一级将制定和测试的数据 通过实验获得的。 预计，这些结果 实验将提高我们对基本的 肺内气体运输的生理机制， 最终有助于制定选择 机械通气患者的呼吸参数。 该项目还将提供所需的背景知识， 开发改进的局部肺功能诊断工具。

This research project deals with the study of regional distribution of pulmonary ventilation in the non-homogeneous lung. It is intended to test the hypothesis that respiratory frequency and tidal volume should affect the regional distribution of alveolar ventilation in different ways depending on the state of parenchyma and airways. The aim of this research is to study in living dogs, the effects of respiratory frequency and tidal volume, mean lung volume and interegional mixing, on the regional distribution alveolar ventilation under three distinct conditions of non-homogeneous lung mechanisms: 1) Large airway obstruction created with a bronchoscopically inserted, known crossectional area orifice; 2) unilateral bronchoconstriction produced by histamine in aerosol, and 3) unilateral low compliance caused by lung lavage. Alveolar ventilation will be assessed by measuring the local turnover rate, from the lung airspaces, of radio-active Nitrogen- 13 during washout maneuvers using a 2D positron camera, or a stationary positron emission ring tomographic camera. This unique ring camera creates 3 dimensional reconstructions of the lungs with excellent spacial resolution. Regional distribution of gas transport created with several settings of conventional and high frequency small-tidal volume mechanical ventilation will be measured. Simultaneously, regional mechanical characteristics and oscillatory flow rates will be measured or estimated, using a combination of newly developed intra-airway pneumotachographs, novel techniques with the positron cameras and computer model of lung mechanics. Theoretical models that incorporate the mechanical and gas transport characteristics of the lung at a regional level will be developed and tested against the data obtained experimentally. It is expected that the results of these experiments will improve our understanding of the basic physiologic mechanisms of gas transport within the lung and ultimately contribute in developing a rationale for selecting the respiratory parameters in the mechanically ventilated patient. This project will also provide the background knowledge needed to develop improved diagnostic tools of regional pulmonary function.