Pulse oximeter
First Claim
1. A pulse oximeter for obtaining an oxygen saturation in a blood, comprising:
- a light emitter, adapted to irradiate a living tissue with light beams having five different wavelengths;
a light receiver, adapted to receive respective light beams reflected from or transmitted through the living tissue, and to convert the received light beams to electric signals;
a first calculator, which calculates five attenuation changes of the living tissue based on fluctuations of the respective electric signals;
a second calculator, which calculates at least four attenuation change ratios from the five attenuation changes, each of the attenuation change ratios being defined by a ratio between any two of the five attenuation changes; and
a third calculator, which calculates the oxygen saturation based on the attenuation change ratios, while taking an oxygen saturation of arterial blood, an oxygen saturation of venous blood, a ratio between changes in arterial blood and venous blood, and a tissue term as four unknown values.
2 Assignments
0 Petitions
Accused Products
Abstract
In a pulse oximeter for obtaining an oxygen saturation in a blood, a light emitter irradiates a living tissue with light beams having five different wavelengths. A light receiver receives respective light beams reflected from or transmitted through the living tissue, and converts the received light beams to electric signals. A first calculator calculates five attenuation changes of the living tissue based on fluctuations of the respective electric signals. A second calculator calculates at least four attenuation change ratios from the five attenuation changes. Each of the attenuation change ratios is defined by a ratio between any two of the five attenuation changes. A third calculator calculates the oxygen saturation based on the attenuation change ratios, while taking an oxygen saturation of arterial blood, an oxygen saturation of venous blood, a ratio between changes in arterial blood and venous blood, and a tissue term as four unknown values.
-
Citations
2 Claims
-
1. A pulse oximeter for obtaining an oxygen saturation in a blood, comprising:
-
a light emitter, adapted to irradiate a living tissue with light beams having five different wavelengths;
a light receiver, adapted to receive respective light beams reflected from or transmitted through the living tissue, and to convert the received light beams to electric signals;
a first calculator, which calculates five attenuation changes of the living tissue based on fluctuations of the respective electric signals;
a second calculator, which calculates at least four attenuation change ratios from the five attenuation changes, each of the attenuation change ratios being defined by a ratio between any two of the five attenuation changes; and
a third calculator, which calculates the oxygen saturation based on the attenuation change ratios, while taking an oxygen saturation of arterial blood, an oxygen saturation of venous blood, a ratio between changes in arterial blood and venous blood, and a tissue term as four unknown values.
-
-
2. A method of obtaining an oxygen saturation in a blood, comprising steps of:
-
irradiating a living tissue with light beams having five different wavelengths;
receiving respective light beams reflected from or transmitted through the living tissue;
converting the received light beams to electric signals;
calculating five attenuation changes of the living tissue based on fluctuations of the respective electric signals;
calculating at least four attenuation change ratios from the five attenuation changes, each of the attenuation change ratios being defined by a ratio between any two of the five attenuation changes; and
calculating the oxygen saturation based on the attenuation change ratios, while taking an oxygen saturation of arterial blood, an oxygen saturation of venous blood, a ratio between changes in arterial blood and venous blood, and a tissue term as four unknown values.
-
Specification