THE DIGITAL BLOOD FLOW, ARTERIAL PRESSURE, AND VASCULAR RESISTANCE IN ARTERIAL HYPERTENSION AND IN CORONARY THROMBOSIS

Open Access
Publisher Website
Google Scholar
Abstract
Methods for calculating the digital blood flow from calorimetric observations were modified by adding the hydrothermic equivalent of the finger tip (vol. in cc. multiplied by 0.8) to the other hydro-thermic equivalents of the calorimeter and by substituting 0.9 for 1.0 as the specific heat of the blood. Digital vascular resistance was calculated in arbitrary units from the formula, R=P/FK, in which P is the effective digital blood pressure in mm. Hg, F is the blood flow in cc. per sq. cm. per min., and K is a constant (0.3). After vasodilatation produced by warming the body, normal digital blood pressure, blood flow, and vascular resistance were found in patients with neurogenic elevations of blood pressure. A consistent increase in digital vascular resistance and a normal digital blood flow were demonstrated in established essential or renal hypertension. In acute and in malignant hypertension, the digital blood flow may be decreased, and the vascular resistance increased out of proportion to the elevation in blood pressure. Decrease in digital blood flow and blood pressure and unchanged vascular resistance were demonstrated in cases of acute coronary occlusion, whether the antecedent blood pressure was normal or elevated.