Investigation of arterial obstruction using a mercury-in-rubber strain gauge

Abstract

The use of the mercury-in-rubber strain gauge to measure the circulation to the limbs is described. The instrument is quickly applied to the limb and can be used to make measurements of the circulation at many points on the limb. It has been used to measure blood flow, volume pulse, and systolic pressure at different levels on the limbs of normal subjects under various conditions and of patients with arterial disease. The range of these measurements in the legs of normal subjects is defined. The measurement of the systolic pressure gradient down the limb also gives a good indication of the location and degree of arterial obstruction or obstructions. The amplitude of volume pulse has been found to be a better indication of the location and severity of chronic arterial obstruction than are measurements of blood flow. This finding led to a consideration of the relationship between blood flow and amplitude of the volume pulse. An argument is put forward for considering the volume pulse as an indication of the degree of reserve of the peripheral circulation. The clinical application of the results in the selection of patients for arterial surgery is considered, and means are suggested by which an oscillometer could be used to provide information on the location and severity of obstruction of the larger arteries.