PULMONARY MICROCIRCULATORY HEMODYNAMICS

血液在肺毛细血管中停留的时间是重要的 肺的气体交换效率的决定因素。 因此， 改变接触时间的生理机制可能具有重要意义 监管职能。 例如，在运动过程中，某些因素会降低 接触时间使每单位有更多的红细胞穿过毛细血管 时间，从而增强气体交换。 然而，如果运输时间变成 太快，可能导致动脉低氧血症。 显而易见的重要性 了解肺微循环血流动力学如何调节 引发了大量研究，但之前的研究人员被迫 使用间接技术，就红细胞毛细血管而言 通过时间，将肺视为一个单一的、同质的实体。 在 事实上，内部压力和流量的区域差异很可能是存在的。 肺部引起毛细血管运输的区域差异。 使用于 我们最近开发的活体视频荧光显微镜技术，我们 建议直接确定红血需要的时间长度 细胞穿过肺毛细血管并评估通过时间 作为生理变量（肺动脉和 静脉压、心输出量和肺毛细血管募集）。 特别强调研究减少运输时间的机制 以增加气体交换。 最后我们将确定站点 荧光素标记的中性粒细胞的隔离和转运时间 细胞正常且激活。

The time that blood spends in the pulmonary capillaries is a major determinant of the gas exchange effectiveness of the lungs. Consequently, physiologic mechanisms which alter this contact time may serve important regulatory functions. For example, during exercise some factors reduce contact time so that more red blood cells traverse the capillaries per unit time, thereby enhancing gas exchange. If, however, transit times become too rapid, arterial hypoxemia can result. The obvious importance of understanding how pulmonary microcirculatory hemodynamics are regulated have prompted numerous studies, but previous investigators have been forced to use indirect techniques and, in terms of red blood cell capillary transit time, to consider the lung as a single, homogeneous entity. In fact, it is likely that regional differences in pressure and flow within the lung give rise to regional differences in capillary transit. Using in vivo video fluorescence microscopy techniques recently developed by us, we propose to determine directly the length of time required for red blood cells to traverse pulmonary capillaries and to evaluate how transit time changes as a function of physiologic variables (pulmonary arterial and venous pressures, cardiac output, and pulmonary capillary recruitment). Specific emphasis is placed on studying mechanisms that reduce transit time in order to increase gas exchange. Finally, we will determine the site of sequestration and transit time of fluorescein labeled neutrophils when the cells are normal and activated.