Beck K C, Lai-Fook S J
J Appl Physiol (1985). 1985 Jun;58(6):2004-10. doi: 10.1152/jappl.1985.58.6.2004.
To obtain a detailed description of the dependence of pulmonary blood flow on changes in lung volume, we perfused isolated rabbit lungs with homologous blood at 37 degrees C while controlling vascular pressures during lung deflation. We set pulmonary arterial pressure (Ppa) and pulmonary venous pressure (Ppv) to constant values relative to alveolar pressure (Palv) to keep the effective driving pressure for flow constant during lung deflation from total lung capacity (TLC) to 25% TLC. The shapes of the flow vs. lung volume curves were dependent on the levels of Ppa-Palv and Ppv-Palv at which they were obtained. When Ppv greater than Palv throughout the lung (zone 3 conditions), flow increased as the lungs were deflated from TLC, independent of the level of Ppa-Palv. When Ppv less than Palv (zone 2 conditions) and Ppa-Palv was moderately high, flow increased as the lungs were deflated from 100 to approximately 50% TLC, then decreased at lower lung volumes. When Ppa - Palv was less than 10 cmH2O in zone 2 conditions, flow decreased monotonically during deflation from TLC. We concluded that the dependence of blood flow on lung volume is complex, which may be a reflection of the nonlinear pressure-diameter properties of pulmonary vessels.
为了详细描述肺血流量对肺容积变化的依赖性，我们在37℃下用同源血液灌注离体兔肺，同时在肺萎陷过程中控制血管压力。我们将肺动脉压（Ppa）和肺静脉压（Ppv）相对于肺泡压（Palv）设定为恒定值，以便在肺从肺总量（TLC）萎陷到25%TLC的过程中，使血流的有效驱动压力保持恒定。血流与肺容积曲线的形状取决于获取这些曲线时Ppa - Palv和Ppv - Palv的水平。当整个肺内Ppv大于Palv（区域3条件）时，随着肺从TLC萎陷，血流增加，与Ppa - Palv的水平无关。当Ppv小于Palv（区域2条件）且Ppa - Palv适度较高时，随着肺从100%萎陷到约50%TLC，血流增加，然后在更低的肺容积时血流减少。当在区域2条件下Ppa - Palv小于10 cmH₂O时，在从TLC萎陷过程中血流单调减少。我们得出结论，血流对肺容积的依赖性很复杂，这可能反映了肺血管非线性的压力 - 直径特性。
