Influence of lung volume on pulmonary microvascular pressure-volume characteristics.
Influence of lung volume on pulmonary microvascular pressure-volume characteristics.
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肺容量对肺微血管压力-容量特性的影响。
DOI：
10.1152/jappl.2000.89.4.1591
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发表时间：
2000
期刊：
影响因子：
--
通讯作者：
Butler,JP
中科院分区：
文献类型：
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作者：
Topulos,GP;Brown,RE;Butler,JP
肺微循环的压力-容积（P-V）特性是肺灌注模式和红、白色细胞通过时间的重要决定因素。使用漫射光散射，我们测量了毛细血管P-V循环在7个切除灌注狗叶在四个肺容量，从功能残气量（FRC），总肺容量（TLC），在广泛的血管跨壁压（Ptm）。在Ptm 5 cmH 2 O时，FRC附近微血管的比顺应性为8.6%/cmH 2 O，随着肺容量增加至TLC，微血管的比顺应性降低至2.7%/cmH 2 O。在低肺容量时，血管显示应变硬化迹象（比顺应性随Ptm升高而下降），但随着肺容量增加，硬化程度降低，TLC时基本不存在。P-V环平滑，无急剧过渡，与血管扩张一致，血管扩张是血管容积变化的主要模式，伴随Ptm变化。在所有肺容积下，滞后都很小（0.013），这表明，尽管表面张力可能会设定基础毛细血管形状，但它不会强烈影响毛细血管顺应性。
The pressure-volume (P-V) characteristics of the lung microcirculation are important determinants of the pattern of pulmonary perfusion and of red and white cell transit times. Using diffuse light scattering, we measured capillary P-V loops in seven excised perfused dog lobes at four lung volumes, from functional residual capacity (FRC) to total lung capacity (TLC), over a wide range of vascular transmural pressures (Ptm). At Ptm 5 cmH2O, specific compliance of the microvasculature was 8.6%/cmH2O near FRC, decreasing to 2.7%/cmH2O as lung volume increased to TLC. At low lung volumes, the vasculature showed signs of strain stiffening (specific compliance fell as Ptm rose), but stiffening decreased as lung volume increased and was essentially absent at TLC. The P-V loops were smooth without sharp transitions, consistent with vascular distension as the primary mode of changes in vascular volume with changes in Ptm. Hysteresis was small (0.013) at all lung volumes, suggesting that, although surface tension may set basal capillary shape, it does not strongly affect capillary compliance.