Apparatus for measuring/determining concentrations of light absorbing materials in blood

• US 20020038078A1
• Filed: 09/24/2001
• Published: 03/28/2002
• Est. Priority Date: 09/22/2000
• Status: Abandoned Application

• Current Assignee: Nihon Kohden Corporation
• Original Assignee: Nihon Kohden Corporation
• Inventors: Ito, Kazumasa
• Application Number:
  US09/960,740
• Publication Number:
  US 20020038078A1
• Time in Patent Office: Days
• US Class Current: 600/309
• CPC Class Codes: A61B 5/14551 for measuring blood gases

Abstract

An apparatus for measuring/determining concentrations of light absorbing materials in blood includes a probe 10 and a measurement device main body 30. A plurality of optical signals of different wavelengths are irradiated onto living tissue, and the concentrations of light absorbing materials in blood is determined by means of a photoplethysmogram detected by means of the light that has transmitted through the tissue. Simulating-signal generating means is provided in the measurement device main body and generates an arbitrary simulating-pulse-wave signal corresponding to the photoplethysmogram detected by the probe.

Claims

1. An apparatus for measuring/determining concentrations of light absorbing materials in blood comprising:

a probe for detecting a photoplethysmogram by irradiating and passing a plurality of optical signals of different wavelengths onto and through a living tissue;

a measurement device main body for determining concentrations of light absorbing materials in blood on the basis of the pulse spectrophotometry;

simulating-signal generating means, for generating an arbitrary simulating-pulse-wave signal corresponding to the photoplethysmogram detected by the probe, provided in the measurement device main body.

2. The apparatus for measuring/determining concentrations of light absorbing materials in blood as claimed in claim 1, wherein the probe irradiate the optical signals in the probe on the basis of the simulating pulse wave signal to detect a simulating-pulse-wave.

3. The apparatus for measuring/determining concentrations of light absorbing materials in blood according to claim 1, further comprising:

means for performing a self checkup function based on a result of processing of the simulating-pulse-wave in the device main body.

4. The apparatus for measuring/determining concentrations of light absorbing materials fin blood according to claim 1, wherein the simulating signal generating means controls a time period for irradiating respective light-emitting diodes in accordance with the simulating-pulse-wave signal through pulse-width modulation (PWM) control to obtain a required simulating-pulse-wave received-light signal.

5. The apparatus for measuring/determining concentrations of light absorbing materials in blood according to claim 1, wherein the simulating signal generating means controls an extraction time required for demodulating a received-light signal stemming from emitting of respective light-emitting diodes being irradiated in accordance with the simulating-pulse-wave signal through pulse width modulation (PWM) control to produce a required simulating-pulse-wave received-light signal.

6. An apparatus for measuring/determining concentrations of light absorbing materials in blood comprising:

a measurement device main body determining concentrations of light absorbing materials in blood on the basis of a photoplethysmogram detected by irradiating and passing a plurality of optical signals of different wavelengths onto and through a living tissue;

simulating-signal generating means, for generating an arbitrary simulating-pulse-wave signal corresponding to the photoplethysmogram detected by a probe, provided in the measurement device main body

a bypass interconnection, arranged in the measurement device main body, routed so as to bypass a probe to be adapted; and

signal switching means for selectively inputting the photoplethysmogram detected by the probe and the simulating-pulse-wave signal which is transmitted through the bypass interconnection into a signal input section of the measurement device main body.

7. The apparatus for measuring/determining concentrations of light absorbing materials in blood according to claim 6, wherein the simulating-pulse-wave signal produced by the simulating signal generating means identifies an anomalous condition of the measurement device main body as a self checkup function in such a manner that the signal switching means selectively inputs, to the signal input section, a signal transmitted through the bypass interconnection and a signal which is detected as a simulating photoplethysmogram by receiving the optical signals having been irradiated corresponding to the simulating-pulse-wave signal in the probe.

8. The apparatus for measuring/determining concentrations of light absorbing materials in blood according to claim 6, wherein the simulating-pulse-wave signal produced by the simulating signal generating means identifies a normal operating state of the apparatus, an anomalous condition of the probe, and an anomalous condition of the measurement device main body, as a self checkup function in such a manner that the signal switching means selectively inputs, to the signal input section, a signal transmitted through the bypass interconnection and a received-light signal corresponding to the simulating-pulse-wave signal which is detected as a result of the optical signals having been irradiated in the probe.

9. The apparatus for measuring/determining concentrations of light absorbing materials in blood according to claim 8, further comprising:

a display section for displaying an checkup status of the apparatus, a normal operating status of the apparatus, an anomalous condition of the probe, and an anomalous condition of the measurement device main body.

10. The apparatus for measuring/determining concentrations of light absorbing materials in blood according to claim 6 further comprising:

signal conversion means, for converting the simulating-pulse-wave signal into a photoplethysmogram signal detected by the probe, provided with the bypass interconnection.

11. The apparatus for measuring/determining concentrations of light absorbing materials in blood according to claim 6, wherein the simulating signal generating means controls a time period for irradiating respective light-emitting diodes in accordance with the simulating-pulse-wave signal through pulse-width modulation (PWM) control to obtain a required simulating-pulse-wave received-light signal.

12. The apparatus for measuring/determining concentrations of light absorbing materials in blood according to claim 11, wherein the shape of a simulating pulse wave is set in accordance with a pulse-width modulation (PWM) pattern and in connection with a relationship between the pulse-width modulation (PWM) and a simulating-pulse-wave received-light signal.

13. The apparatus for measuring/determining concentrations of light absorbing materials in blood according to claim 11, wherein a pulsation component rate (the ratio between an AC component and a DC component) of a simulating pulse wave is set in accordance with a pulse-width modulation (PWM) ratio and in connection with a relationship between the pulse-width modulation (PWM) and a simulating-pulse-wave received-light signal.

14. The apparatus for measuring/determining concentrations of light absorbing materials in blood according to claim 11, wherein a simulating pulse rate is set in accordance with a modulation cycle and in connection with a relationship between the pulse-width modulation and a simulating-pulse-wave (PWM) received-light signal.

15. The apparatus for measuring/determining concentrations of light absorbing materials in blood according to claim 11, wherein a parameter pertaining to an absorption coefficient rate is set on the basis of a modulation ratio proportion between wavelengths and in connection with a relationship between the pulse-width modulation (PWM) and a simulating-pulse-wave received-light signal.

16. The apparatus for measuring/determining concentrations of light absorbing materials in blood according to claim 11, wherein the simulating-pulse-wave signal is formed from integral values obtained by integrating separated light-receiving time by a demodulation circuit section to each wavelength.

17. The apparatus for measuring/determining concentrations of light absorbing materials in blood according to claim 6, wherein the simulating signal generating means controls an extraction time required for demodulating a received-light signal stemming from emitting of respective light-emitting diodes being irradiated in accordance with the simulating-pulse-wave signal through pulse width modulation control to produce a required simulating-pulse-wave (PWM)received-light signal.

18. The apparatus for measuring/determining concentrations of light absorbing materials in blood according to claim 17, wherein the shape of a simulating pulse wave is set in accordance with a pulse-width modulation (PWM) pattern and in connection with a relationship between the pulse-width modulation (PWM) and a simulating-pulse-wave received-light signal.

19. The apparatus for measuring/determining concentrations of light absorbing materials in blood according to claim 17, wherein a pulsation component rate (the ratio between an AC component and a DC component) of a simulating pulse wave is set in accordance with a pulse-width modulation (PWM) ratio and in connection with a relationship between the pulse-width modulation (PWM) and a simulating-pulse-wave received-light signal.

20. The apparatus for measuring/determining concentrations of light absorbing materials in blood according to claim 17, wherein a simulating pulse rate is set in accordance with a modulation cycle and in connection with a relationship between the pulse-width modulation (PWM) and a simulating-pulse-wave received-light signal.

21. The apparatus for measuring/determining concentrations of light absorbing materials in blood according to claim 17, wherein a parameter pertaining to an absorption coefficient rate is set on the basis of a modulation ratio proportion between wavelengths and in connection with a relationship between the pulse-width modulation (PWM) and a simulating-pulse-wave received-light signal.

22. The apparatus for measuring/determining concentrations of light absorbing materials in blood according to claim 17, wherein the simulating-pulse-wave signal is formed from integral values obtained by integrating separated light-receiving time by a demodulation circuit section to each wavelength.