Non-invasive measuring method and apparatus of blood constituents
AssigneeOmron Tateisi Electronics Co.
InventorsToshikazu Shiga, Takuji Suzaki
Life of this patent
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Abstract
In order to measure the oxygen saturation in venous blood, a venous blood stream is made time-variant by applying pressure with a peak value of the minimum blood pressure to a proximal portion from a measuring part. Light beams with different wavelengths are transmitted from the measuring part and detected by photodiodes. Photodetected signals are logarithm-converted and venous signal components are separated from logarithm-converted signals with a filter circuit. The oxygen saturation of venous blood is calculated on the basis of separated venous signal components.
Claims8
An apparatus for measuring a blood constituent in a living body, comprising:
- light source means for illuminating a measuring part of said living body by at least two kinds of light beams with different wavelength components;
- photodetecting means for detecting light beams transmitted from said measuring part;
- logarithm-converting means for logarithm-converting photodetected signals outputted from said photodetecting means;
- signal separation means for separating time-variant venous signal components corresponding to respective wavelength components from logarithm-converted signals;
- pressure application means for applying pressure to a proximal portion from said measuring part;
- and
- computing means for controlling said pressure application means so that said pressure may change with a peak value being about the minimum blood pressure and calculating a venous blood constituent characteristic on the basis of said venous signal components separated by said signal processing means.
A method for measuring a blood constituent in a living body, comprising the steps of:
- applying pressure to a proximal portion from a measuring part of said living body so that said pressure may change with a peak value being about the minimum blood pressure;
- illuminating said measuring part by at least two kinds of light beams with different wavelength components;
- detecting light beams transmitted from said measuring part;
- logarithm-converting photodetected signals;
- separating time-variant venous signal components corresponding to respective wavelength components from logarithm-converted signals;
- and
- calculating a venous blood constituent characteristics on the basis of separated venous signal components.
Dependencies are inferred from the claim text.