PULSE PHOTOMETER AND METHOD FOR CALCULATING CONCENTRATION OF LIGHT ABSORBER IN BLOOD

• US 20160256089A1
• Filed: 03/03/2016
• Published: 09/08/2016
• Est. Priority Date: 03/04/2015
• Status: Active Grant

• Current Assignee: Nihon Kohden Corporation
• Original Assignee: Nihon Kohden Corporation
• Inventors: UEDA, Yoshinori, UKAWA, Teiji, ITO, Kazumasa, FUJISAKI, Hideki
• Granted Patent: US 10,524,704 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: A61B 5/14551 for measuring blood gases
• CPC Class Codes: A61B 5/72 Signal processing specially adapted for physiological signals or for diagnostic purposes character recognition, recognising digital ink, document-oriented image-based pattern recognition G06V30/00; recognition or understanding of postal images G06V30/424

Abstract

A pulse photometer includes: a first variation acquirer acquiring a first variation corresponding to a light attenuation variation of a first light beam due to pulsation of blood in a subject, based on a first intensity signal corresponding to an intensity of the first light beam that is transmitted through or reflected from a body of the subject, and that has a first wavelength; a second variation acquirer acquiring a second variation; and a concentration calculator calculating a blood light absorber concentration, based on the first and second variations, the second variation containing a first offset which is based on an inverse of the light attenuation variation of the first light beam.

Claims

1. A pulse photometer comprising:

a first light emitter which is configured to emit a first light beam having a first wavelength;

a second light emitter which is configured to emit a second light beam having a second wavelength;

a light detector which is configured to output a first intensity signal in accordance with an intensity of the first light beam that is transmitted through or reflected from a body of a subject, and a second intensity signal in accordance with an intensity of the second light beam that is transmitted through or reflected from the body of the subject;

a first variation acquirer which is configured to acquire a first variation corresponding to a light attenuation variation of the first light beam due to the pulsation of the blood in the subject, based on the first intensity signal;

a second variation acquirer which is configured to acquire a second variation corresponding to a light attenuation variation of the second light beam due to the pulsation of the blood in the subject, based on the second intensity signal; and

a concentration calculator which is configured to calculate a blood light absorber concentration, based on the first variation and the second variation,

the second variation containing a first offset which is based on an inverse of the light attenuation variation of the first light beam.

2. The pulse photometer according to claim 1, wherein

the first offset which is a constant that is previously statistically determined based on a plurality of blood light absorber concentrations acquired from a plurality of subjects.

3. The pulse photometer according to claim 1, wherein

one of the first light beam and the second light beam is a red light beam, and

the other of the first light beam and the second light beam is an infrared light beam.

4. The pulse photometer according to claim 1, further comprising:

a third light emitter; and

a third variation acquirer, wherein

the third light emitter is configured to emit a third light beam having a third wavelength,

the light detector is configured to output a third intensity signal in accordance with an intensity of the third light beam that is transmitted through or reflected from the body of the subject,

the third variation acquirer is configured to acquire a third variation corresponding to a light attenuation variation of the third light beam due to the pulsation of the blood in the subject, based on the third intensity signal,

the concentration calculator is configured to calculate the blood light absorber concentration, based on the first variation, the second variation, and the third variation, and

the third variation contains a second offset which is based on an inverse of the light attenuation variation of the first light beam.

5. The pulse photometer according to claim 4, wherein

the second offset is a constant that is previously statistically determined based on a plurality of blood light absorber concentrations acquired from a plurality of subjects.

6. The pulse photometer according to claim 4, wherein

the first wavelength, the second wavelength, and the third wavelength are selected from 630 nm, 660 nm, 700 nm, 730 nm, 805 nm, 880 nm, and 940 nm.

7. A pulse photometer comprising:

a first variation acquirer which is configured to acquire a first variation corresponding to a light attenuation variation of a first light beam due to pulsation of blood in a subject, based on a first intensity signal corresponding to an intensity of the first light beam that is transmitted through or reflected from a body of the subject, and that has a first wavelength;

a second variation acquirer which is configured to acquire a second variation corresponding to a light attenuation variation of a second light beam due to the pulsation of the blood in the subject, based on a second intensity signal corresponding to an intensity of the second light beam that is transmitted through or reflected from the body of the subject, and that has a second wavelength; and

a concentration calculator which is configured to calculate a blood light absorber concentration, based on the first variation and the second variation,

the second variation containing a first offset which is based on an inverse of the light attenuation variation of the first light beam.

8. A method for calculating a blood light absorber concentration, the method comprising:

causing a pulse photometer to acquire a first variation corresponding to a light attenuation variation of a first light beam due to pulsation of blood in a subject, based on a first intensity signal corresponding to an intensity of the first light beam that is transmitted through or reflected from a body of the subject, and that has a first wavelength;

causing the pulse photometer to acquire a second variation corresponding to a light attenuation variation of a second light beam due to the pulsation of the blood in the subject, based on a second intensity signal corresponding to an intensity of the second light beam that is transmitted through or reflected from the body of the subject, and that has a second wavelength; and

causing the pulse photometer to calculate the blood light to absorber concentration, based on the first variation and the second variation,

the second variation containing a first offset which is based on an inverse of the light attenuation variation of the first light beam.