REGIONAL VENTILATION IN THE NON-HOMOGENEOUS LUNG

本研究项目是关于区域分布的研究。 在非均质肺中的肺通气性。它是 旨在检验呼吸频率和呼吸频率 潮气量应影响肺泡的区域分布 通风方式不同，视情况而定 实质和呼吸道。这项研究的目的是研究在 活着的狗，呼吸频率和潮气量的影响， 区域平均肺体积和区域间混合 肺泡通气量在三种不同状态下的分布 非均质性肺机制：1)大气道阻塞 用支气管镜插入的已知横断面 面积开口；2)单侧支气管壁收缩 气雾剂中的组胺，以及3)由以下因素引起的单侧低依从性 肺灌洗。 将通过测量局部肺泡通气量来评估肺泡通气量 从肺部空气中，放射性氮的周转率- 13在使用2D正电子相机或 固定式正电子发射环形层析相机。这 独特的环形摄像机创建了 肺部具有极佳的空间分辨率。的地区分布 使用几种常规设置和 高频小潮气量机械通气法 量过了。同时，区域力学特征 和振荡流速将被测量或估计，使用 结合新开发的呼吸道内气体测定仪， 正电子相机和计算机模型的新技术 肺力学的研究。理论模型结合了 老年患者肺的机械和气体传输特性 将根据数据开发和测试区域级别 是通过实验获得的。预计这些结果将会 实验将提高我们对基本知识的理解 气体在肺内和肺内转运的生理机制 最终有助于形成选择 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 开发改进的区域肺功能诊断工具。

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.