Measurement device for intracardial acquisition of blood oxygen saturation

Abstract

A measurement device for frequency control of a heart pacemaker based on the level of blood oxygen saturation contains a measuring probe which includes a light transmitter and a light receiver. The light receiver receives the light emitted by the light transmitter and reflected by the blood. The light transmitter and the light receiver are connected in parallel to an evaluation circuit via two common lines, this evaluation circuit charging the measuring probe with a constant current or with a constant voltage. A resistor is arranged in series with the light receiver. A transistor is arranged parallel to this series circuit, the base thereof being connected to the junction of the resistor and the light receiver. By means of this arrangement, the measurement sensitivity given deposits on the probe is maintained at a higher level. In an alternative embodiment, this can also be achieved using a resistor in series with the light transmitter with a transistor controlled by the light receiver connected in parallel therewith.

Dependencies are inferred from the claim text.