Baker C H, Davis D L, Sutton E T
Circ Shock. 1979;6(1):61-74.
The effects of stepwise hemorrhages on plasma flow velocity and indicator (FITC-Dextran) dispersion in series and parallel coupled microvascular vessels has been studied. The mesentery of cats (0.6 kg) anesthetized with Dial-Urethane was exposed and studied with a microscope equipped for fluorescense microscopy. Indicator was injected as a bolus (0.1 ml in 0.5 seconds) in a small branch of the mesenteric artery. Indicator curves were recorded from a video tape recording of the passage of the indicator by a video sampler with intensity sensitive windows. The mean transit time (t), appearance time (t(a)), peak time (t(p)), curve duration (t(E)), plasma velocity and vessel diameter changes were determined. Arterioles 68 +/- 8 micron and 35 +/- 3 micron and venules 55 +/- 6 micron constricted gradually with hemorrhage. Arterioles 20 +/- 2 micron constricted with mild hemorrhage and remained constricted with further hemorrhage. Arteriolar and venular plasma velocities decreased abruptly with mild hemorrhage and then continued to decrease gradually with further hemorrhage. Capillary flow ceased after moderate hemorrhage and was not reestablished until at least an hour after reinfusion. Arteriole t increased with hemorrhage but t increased much more in capillaries and venules. t(E) changes paralled t changes. The ratio t(a)/t was lower for venules than arterioles and both decreased with hemorrhage but the venular ratio decreased significantly more. Venular t(p)-t(a) and t(E)-t(p) increased more than arteriolar values. Hemorrhage increased indicator dispersion with the greatest effect occurring between the arteriolar and venular vessels.
研究了逐步出血对串联和并联耦合微血管中血浆流速及指示剂（异硫氰酸荧光素 - 葡聚糖）弥散的影响。暴露并用配备荧光显微镜的显微镜研究用二溴乙烷麻醉的猫（0.6千克）的肠系膜。指示剂以团注形式（0.5秒内注入0.1毫升）注入肠系膜动脉的一个小分支。通过具有强度敏感窗口的视频采样器从指示剂通过的录像带记录中记录指示剂曲线。测定平均通过时间（t）、出现时间（t(a)）、峰值时间（t(p)）、曲线持续时间（t(E)）、血浆流速和血管直径变化。直径为68±8微米和35±3微米的小动脉以及直径为55±6微米的小静脉随着出血逐渐收缩。直径为20±2微米的小动脉在轻度出血时收缩，并在进一步出血时持续收缩。小动脉和小静脉的血浆流速在轻度出血时突然下降，然后随着进一步出血继续逐渐下降。中度出血后毛细血管血流停止，直到再灌注后至少一小时才重新建立。小动脉的t随着出血增加，但毛细血管和小静脉中的t增加得更多。t(E)的变化与t的变化平行。小静脉的t(a)/t比值低于小动脉，两者都随着出血而降低，但小静脉的比值下降得更显著。小静脉的t(p)-t(a)和t(E)-t(p)比小动脉的值增加得更多。出血增加了指示剂的弥散，在小动脉和小静脉之间产生的影响最大。
