Francis T J, McCaig R H
Eur J Appl Physiol Occup Physiol. 1985;54(4):404-12. doi: 10.1007/BF02337185.
Blood flow in the right foot of 11 subjects was measured simultaneously by a strain gauge placed around the mid metatarsal circumference of the foot and a water displacement plethysmograph in which the foot was resting. A close linear correlation (r = 0.88) between the results of the two methods existed over a wide range of blood flows. It was apparent however that blood flow at the mid metatarsal region of the foot was only about 30% of the total foot blood flow measured by the plethysmograph. The likely cause of this finding is the varying proportion of bone to soft tissue along the length of the foot. It was observed that the strain gauge estimates of blood flow increased two to three fold when the plethysmograph was emptied, an effect that was abolished by refilling the plethysmograph. These changes were highly statistically significant (P less than 0.01) in all ten subjects in whom this comparison was made. The application of progressively increasing hydrostatic pressure in a further 4 subjects demonstrated that the reduction in blood flow was proportional to the pressure applied. Explanations for this effect based upon small temperature and pressure changes altering strain gauge performance are excluded. Three mechanisms are proposed, based upon an increase in venous leakage, a reduction in arterial inflow and the consequence of increased capillary filling occurring as a result of hydrostatic pressure within the plethysmograph.
通过放置在足部跖骨中部周围的应变仪和足部处于静止状态的排水体积描记器，同时测量了11名受试者右足的血流情况。在广泛的血流范围内，两种方法的结果之间存在密切的线性相关性（r = 0.88）。然而，很明显，足部跖骨中部区域的血流仅约为体积描记器测量的足部总血流的30%。这一发现的可能原因是沿足部长度方向骨骼与软组织的比例不同。观察到当体积描记器排空时，应变仪对血流的估计增加了两到三倍，重新填充体积描记器后这种效应消失。在进行此比较的所有10名受试者中，这些变化具有高度统计学意义（P小于0.01）。在另外4名受试者中逐渐增加静水压力的应用表明，血流减少与施加的压力成正比。基于小的温度和压力变化改变应变仪性能的这种效应的解释被排除。提出了三种机制，基于静脉渗漏增加、动脉流入减少以及体积描记器内静水压力导致的毛细血管充盈增加的结果。
