Sutton D W, Schmid-Schönbein G W
Department of Applied Mechanics and Engineering Sciences, Bioengineering, University of California, San Diego, La Jolla 92093.
Am J Physiol. 1989 Nov;257(5 Pt 2):H1419-27. doi: 10.1152/ajpheart.1989.257.5.H1419.
The low flow arterial pressure-flow relationship and zero-flow pressure (ZFP) are investigated in the hemodynamically isolated gracilis muscle using a high precision pump. The muscle is kept in situ with dilated vasculature. During steady-state perfusion, using a plasma-like medium, the pressure-flow curve is nonlinear with positive arterial ZFP of 3.5-12 mm Hg when normal central circulation pressure is present. When the central circulation is stopped the ZFP reduces to zero. Addition of nonaggregated red blood cells (RBCs) results in no significant increase in the ZFP; however, introduction of aggregated RBCs (with dextran, 77 kDa) causes a 9.4 +/- 1.2 mmHg elevation. The positive ZFPs observed using plasma-like and dispersed RBC perfusions are found to be caused by a back pressure from the central circulation via collateral arterioles. A single-step reduction of the arterial flow rate from a finite value to zero results in a ZFP, which decreases for more than a minute before steady state is reached. During harmonic flow inputs with oscillations down to zero flow, an increase in the ZFP is detected near 0.09 Hz and continues to rise up to the test limit of 10 Hz. Our results suggests that in vasodilated skeletal muscle three independent mechanisms exist, collateral flow, cell aggregation, and unsteady perfusion, which may cause a positive arterial ZFP.
使用高精度泵在血流动力学隔离的股薄肌中研究低流量动脉压-流量关系和零流量压力（ZFP）。该肌肉在血管扩张的情况下保持原位。在使用类血浆介质进行稳态灌注期间，当存在正常的中心循环压力时，压力-流量曲线呈非线性，动脉ZFP为3.5-12 mmHg且为正值。当中心循环停止时，ZFP降至零。添加未聚集的红细胞（RBC）不会导致ZFP显著增加；然而，引入聚集的红细胞（与77 kDa右旋糖酐一起）会导致ZFP升高9.4±1.2 mmHg。发现使用类血浆和分散红细胞灌注观察到的正ZFP是由中心循环通过侧支小动脉产生的背压引起的。将动脉流速从有限值单步降至零会导致ZFP出现，在达到稳态之前，ZFP会下降超过一分钟。在谐波流量输入且振荡直至零流量的过程中，在接近0.09 Hz时检测到ZFP增加，并持续上升至10 Hz的测试极限。我们的结果表明，在血管扩张的骨骼肌中存在三种独立的机制，即侧支血流、细胞聚集和不稳定灌注，它们可能导致动脉ZFP为正。
