Measuring apparatus for the non-invasive detection of venous and arterial blood flow and drainage disorders

Claim 1

A measuring apparatus for the non-invasive detection of peripheral drainage and blood flow disorders in human extremities, the emptying or filling of blood in the veins or arteries of an extremity being detectable in its timely progress, comprising: (a) a measuring head adapted to be affixed to the skin of the extremity; (b) a plurality of radiation sources adapted to emit radiation of the same wave length and mounted in said measuring head spaced from each other for directly contacting the skin, each of said radiation sources being adapted to direct radiation onto a respective area of the skin along a path perpendicular to the skin; (c) means connected to said radiation sources for modulating said radiation sources; (d) a radiation receiver mounted in said measuring head spaced from said plurality of radiation sources for directly contacting the skin and adapted for measuring the amount of radiation reflected or dispersed back by the cutaneous vascular plexus at an area of the skin different from said areas of the skin subjected to radiation from said radiation sources; (e) a temperature sensor mounted in said measuring head for directly contacting the skin and measuring the skin temperature simultaneously with the measurement by said radiation receiver of said reflected or dispersed back radiation; and (f) an electronic evaluation circuit connected to said radiation receiver and to said temperature sensor for selectively detecting and recording the progress of the reflected or dispersed amount of radiation and the skin temperature as functions of time, said electronic evaluation circuit including a low-pass filter with a limit frequency for suppressing interference resulting from modulation of the measured signal from said radiation receiver due to the pulse of blood in the blood vessels of the skin.