Hillier S C, Godbey P S, Hanger C C, Graham J A, Presson R G, Okada O, Linehan J H, Dawson C A, Wagner W W
Department of Anesthesia, Indiana University School of Medicine, Indianapolis 46202.
J Appl Physiol (1985). 1993 Nov;75(5):2106-11. doi: 10.1152/jappl.1993.75.5.2106.
Pulmonary vascular distensibility has an important influence on pulmonary hemodynamics. Although many measurements of distensibility have been made on large pulmonary vessels, there is less information on microvascular distensibility. We have measured the distensibility of the smallest (< 70-microns-diam) precapillary arterioles and postcapillary venules. Isolated dog lobes, at 2.5 cmH2O transpulmonary pressure, were perfused at low flows, which caused the arteriovenous pressure gradient to be very small and thereby permitted accurate estimation of microvascular pressure. As microvascular pressure was systematically varied between 0 and 30 mmHg, subpleural microvascular diameters were determined from computer-enhanced images obtained by videomicroscopy. Arteriolar and venular distensibilities were not different from each other. The microvascular pressure-diameter relationship was alinear with distensibility coefficients of 1-3% mmHg-1, values that are of the same order of magnitude as previously measured distensibilities of 100- to 1,000-microns-diam canine pulmonary vessels.
肺血管可扩张性对肺血流动力学有重要影响。尽管已经对大的肺血管进行了许多可扩张性测量，但关于微血管可扩张性的信息较少。我们已经测量了最小（直径<70微米）的毛细血管前小动脉和毛细血管后小静脉的可扩张性。在2.5 cmH₂O的跨肺压下，对离体狗肺叶进行低流量灌注，这使得动静脉压力梯度非常小，从而能够准确估计微血管压力。随着微血管压力在0至30 mmHg之间系统地变化，通过视频显微镜获得的计算机增强图像确定胸膜下微血管直径。小动脉和小静脉的可扩张性彼此没有差异。微血管压力-直径关系呈线性，可扩张系数为1-3% mmHg⁻¹，该值与先前测量的直径为100至1000微米的犬肺血管的可扩张性处于同一数量级。
