Microprocessor controlled apparatus for the noninvasive determination of peripheral outflow and flow disturbances

摘要

A measuring apparatus for the noninvasive determination of peripheral outflow and flow disturbances in the extremities of human beings includes at least one light transmitter for directing light onto the skin of a human subject and at least one light receiver for receiving reflected light as well as an evaluation and read-out circuit to ascertain the temporal course of blood outflow or inflow in the veins by measuring the changes in the reflected light. The evaluation and read-out circuit calibrates itself prior to measuring by raising the current flowing through the light transmitter or transmitters until the signal-to-noise ratio of the receiver has attained a specific value.