Measurement device for intracardial acquisition of blood oxygen saturation
First Claim
1. A probe for acquiring signals for intracardial measurement of blood oxygen saturation for use with an evaluation circuit having two outputs for charging said probe with a constant electrical operating parameter, said probe comprising:
- two input terminals connectable to evaluation circuit output terminals;
a light transmitter means for transmitting light at blood connected across said input terminals;
a light receiver means for receiving light from said light transmitter reflected by said blood connected across said input terminals; and
a transistor means connected in parallel with said light transmitter for shunting current around said transmitter means and said receiver means; and
means for decreasing the current conductability of said transistor means in response to any increase of current through said light receiver means.
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Accused Products
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.
19 Citations
12 Claims
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1. A probe for acquiring signals for intracardial measurement of blood oxygen saturation for use with an evaluation circuit having two outputs for charging said probe with a constant electrical operating parameter, said probe comprising:
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two input terminals connectable to evaluation circuit output terminals; a light transmitter means for transmitting light at blood connected across said input terminals; a light receiver means for receiving light from said light transmitter reflected by said blood connected across said input terminals; and a transistor means connected in parallel with said light transmitter for shunting current around said transmitter means and said receiver means; and means for decreasing the current conductability of said transistor means in response to any increase of current through said light receiver means. - View Dependent Claims (2, 3, 4, 5, 6)
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7. A measuring probe for acquiring signals for intracardial measurement of blood oxygen saturation for use with an evaluation circuit having two outputs for charging said probe with a constant electrical operating parameter, said probe comprising:
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two input terminals connectable to evaluation circuit output terminals, a light transmitter means for transmitting light at blood connected across said input terminals; a light receiver means for receiving light from said light transmitter reflected by said blood connected across said input terminals; a resistor connected in series with said light transmitter means across said input terminals; and means connected across said resistor for conducting current in parallel to said resistor; and means for reducing the resistance of said means for conducting in response to any increase in current flow through said light receiver means. - View Dependent Claims (8, 9, 10, 11, 12)
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Specification