ON-LINE STUDIES OF PULSATILE PULMONARY HEMODYNAMICS

我提出了一个结合实验和理论的方法来（1）研究 在各种生理条件下的脉动肺血流动力学 和病理条件和（2）改善和相关的两个现有的 血流动力学的研究方法。 长期目标是 项目是双重的：（1）科学地，了解行为的 在脉动流条件下的肺脉管系统，并限制身体 的信息已经获得了稳定流的结果， 脉动流实验;（2）实际上，建立不同的 在不同条件下的阻抗谱的模式，并使用这种 信息作为在线评估肺疾病状态的手段 血流动力学 实验将在犬中进行，有两种基本制剂：（1） 完整的右心和左肺插管，开胸或闭合 （2）离体左肺下叶，原位或体外灌注 通过一个脉动泵。 在第一次制备中，瞬时压力-流量 将准确记录关系， 将在线计算阻抗。 在第二次制备中，动脉 和静脉闭塞（AVO）将以精确和输入的方式应用 还将进行阻抗测量。 这些数据将被分析， 在线和离线。 由于AVO技术提取了血管的脉冲响应， 系统在时域和输入阻抗表征血管 系统在频域中，将尝试将 从这两种方法得到的结果。 在完整右心实验中，压力-流量关系 在肺血管床放电的短暂时间内 被动地将被特别地检查。 左心房的作用 整个肺血管床中的脉动也将 研究了 本项目研究的病理生理条件包括 肺膨胀、缺氧、对血清素、异丙肾上腺素和 去甲肾上腺素，血液稀释，肺栓塞，急性肺 渗透性水肿、静水性水肿、内毒素休克 失血性休克，IPPB通气和PEEP的影响。

I propose a combined experimental-theoretical approach to (1) study pulsatile pulmonary hemodynamics on-line under a variety of physiological and pathological conditions and (2) to improve and correlate two existing methods of investigation in hemodynamics. The long-term objective of this project is two-fold: (1) scientifically, to understand the behavior of the pulmonary vasculature under pulsatile flow conditions and to limit the body of information which has been obtained with steady flow to the results from the pulsatile flow experiments; (2) practically, to establish distinct patterns of the impedance spectra under different conditions and use such information as a means of online evaluation of the state of pulmonary hemodynamics. Experiments will be performed in dogs with two basic preparations: (1) intact right heart and cannulated left lung, either open chest or closed chest; (2) isolated left lower lobe, either in situ or in vitro, perfused by a pulsatile pump. In the first preparation instantaneous pressure-flow relationships will be recorded accurately and pulmonary vascular input impedance will be computed on-line. In the second preparation, arterial and venous occlusion (AVO) will be applied with precision and input impedance measurements will also be made. These data will be analyzed both on-line and off-line. Since the AVO technique elicits the impulse responses of the vascular system in the time-domain and input impedance characterizes the vascular system in the frequency-domain, an attempt will be made to correlate the results obtained from these two methods. In the intact right heart experiments, the pressure-flow relationship during the brief period when the pulmonary vascular bed discharges passively will be examined in particular. The effect of the left atrium on the pulsatility in the entire pulmonary vascular bed will also be investigated. The pathophysiological conditions to be studied in this project include lung inflation, hypoxia, effects on serotonin, isoproterenol and norepinephrine infusion, hemodilution, pulmonary embolism, acute lung injury with permeability edema, hydrostatic edema, endotoxic shock, hemorrhagic shock, and effects of IPPB ventilation and PEEP.