DETERMINANTS OF PULMONARY ARTERY BLOOD VELOCITY PROFILE

目前用于1)非侵入性肺血流定量的方法 使用超声和2)估计肺输入阻抗 腔内速度导管在很大程度上依赖于 主肺动脉血流速度曲线平坦。然而，最近 对人类和动物的研究表明，沿长轴方向的平均轮廓 轴线可能偏向前壁。这种歪曲被归因于 在舒张期和收缩晚期靠近后壁的血流倒置 它们变得更加突出，并延伸到十字架的更大部分 在存在肺动脉高压的情况下的截面积。虽然尝试 血流逆转的幅度和/或持续时间与肺功能的相关性 已经产生了动脉压，但对动脉血压的来源知之甚少 表观回流，2)上升流对速度剖面的影响， 或3)在阻抗相关参数中可能出现的偏差 特性阻抗和第一模极小值的频率 腔内导管放置的结果。这项研究将解决这些问题 通过评估速度剖面和速度分布之间的关系来解决问题 腔内注射20%阿司匹林的动物模型肺血流动力学异常 MHz脉冲多普勒仪。纵断面将沿长线和 用于创建将被关联的二维轮廓的短轴 通过电磁测量的血流量。在以下方面进行的研究 主肺动脉将复制在右肺动脉上，以 确定流动反转现象的程度以及 用右端输入阻抗代替主端输入阻抗的可行性 以评估肺血管损害。慢性 会造成肺动脉高压和/或肺血流量升高 在狗和羔羊身上。一旦获得控制剖面，100%的效果 将对吸氧和肼丙嗪进行评估。我们会作出努力 减少腔内探头改进现有测量方法 完成配置文件所需的大小和时间。在动物模型中的发现 将与患者数据进行比较。主要肺脏的光谱 动脉，目前是通过术中使用电磁获得的 流动探头，将与通过测量速度获得的频谱进行比较 在主肺动脉和右肺动脉使用手持式腔外脉搏 多普勒探头。最后，将努力获得光谱中的 吸氧对右肺动脉影响的研究 在导尿术实验室进行，以评估血管张力 肺血流动力学异常的患者。

Current methodologies for 1) quantifying pulmonary blood flow noninvasively with ultrasound and 2) estimating pulmonary input impedance with intraluminal velocity catheters rely heavily on the assumption that the velocity profile in the main pulmonary artery is flat. However, recent studies in humans and animals indicate that the mean profile along the long axis may be skewed toward the anterior wall. This skew has been attributed to flow reversals near the posterior wall during diastole and late systole which become accentuated and extend over a larger portion of the cross sectional area in the presence of pulmonary hypertension. Though attempts to correlate the magnitude and/or duration of flow reversal with pulmonary artery pressure have been made, little is known about 1) the source of the apparent backflow, 2) the effects of elevated flow on the velocity profile, or 3) discrepancies which may occur in impedance related parameters such as characteristic impedance and frequency of the first modulus minimum as a result of intraluminal catheter position. This study will address these issues by evaluating the relationships between velocity profiles and abnormal pulmonary hemodynamics in animal models using an intraluminal 20 MHz pulsed Doppler device. Profiles will be obtained along the long and short axes to create a two-dimensional profile which will be correlated with electromagnetically measured blood flow. Studies performed on the main pulmonary artery will be duplicated on the right pulmonary artery to determine the extent of the flow reversal phenomena as well as the feasibility of using the input impedance of the right rather than the main pulmonary artery to assess pulmonary vascular impairment. Chronic pulmonary hypertension and/or elevated pulmonary blood flow will be created in dogs and lambs. Once control profiles are obtained, the effects of 100% oxygen inhalation and hydralazine will be evaluated. Efforts will be made to improve current methods of measurement by reducing intraluminal probe size and time needed to complete a profile. Findings in the animal models will be compared to patient data. The spectra in the main pulmonary artery, currently being obtained intraoperatively using electromagnetic flow probes, will be compared to the spectra obtained by measuring velocity in the main and right pulmonary artery with a hand-held extraluminal pulsed Doppler probe. Finally, efforts will be made to obtain spectra in the right pulmonary artery whenever studies of the effects of oxygen inhalation are done in the catheterization laboratory to assess vascular tone in patients with abnormal pulmonary hemodynamics.