Compliance of the Human Pulmonary Arterial System in Disease
Compliance of the Human Pulmonary Arterial System in Disease
复制标题
人类肺动脉系统在疾病中的顺应性
作者：
S. Reuben
对35例心导管术患者进行了肺动脉和肺动脉“楔形”压的测量。根据舒张期肺动脉压力曲线、左房压力和肺血管阻力(R)计算肺动脉顺应性(C)。在肺正常血压组，顺应性平均为2.87毫升/毫米汞柱；在重度肺动脉高压患者中，顺应性低至0.7毫升/毫米汞柱。其中16例患者用N2O体体积描记仪测定肺毛细血管血流量。在肺血压正常的患者中，毛细血管血流的搏动性，即峰值与平均流速的比率为2：1；进展性肺动脉高压与低至1.2：1的值有关，表明血流脉冲明显减弱。搏动指数与肺动脉系统的Rc时间常数有很好的相关性，因此肺毛细血管血流脉冲的衰减与时间常数的延长有关。提示重度肺动脉高压时，肺动脉壁僵硬，不能扩张。提出了一种从肺毛细血管血流脉搏估算平均肺动脉压和左房压的方法，以及顺应性与压力、搏动指数和Rc时间常数之间的关系。因此，N2O体积描记术为肺血管床的研究提供了一种可靠的、可重复的、无创的方法。
Pulmonary arterial and pulmonary arterial “wedge” pressures were measured in 35 patients during cardiac catheterization. Pulmonary arterial compliance (C) was calculated from the diastolic pulmonary arterial pressure profile, left atrial pressure, and pulmonary vascular resistance (R). In the pulmonary normotensive group, compliance averaged 2.87 ml/mm Hg; in patients with severe pulmonary hypertension, values as low as 0.7 ml/mm Hg were found. In 16 of these patients, pulmonary capillary blood flow was measured by N2O body plethysmography. In pulmonary normotensive patients the pulsatility of capillary flow, i.e., the ratio of peak-to-mean flow rates, was 2:1; advanced pulmonary hypertension was associated with values as low as 1.2:1, suggesting marked damping of the flow pulse. The pulsatility index correlated well with the RC time constant of the pulmonary arterial system, so that damping of the pulmonary capillary flow pulse was associated with a prolonged time constant. This suggested that in severe pulmonary hypertension the pulmonary arterial walls are stiff and indistensible. A method was developed for estimating mean pulmonary arterial and left atrial pressure from the pulmonary capillary flow pulse, and the relationships between compliance and pressure and pulsatility index and RC time constant. N2O-plethysmography can thus provide a reliable and repeatable, noninvasive method for investigation of the pulmonary vascular bed.