Biological signal measuring system

• US 10,349,897 B2
• Filed: 12/02/2014
• Issued: 07/16/2019
• Est. Priority Date: 12/04/2013
• Status: Active Grant

• Current Assignee: Nihon Kohden Corporation
• Original Assignee: Nihon Kohden Corporation
• Inventors: Kobayashi, Naoki, Ukawa, Teiji, Ito, Kazumasa, Takeuchi, Masahiro, Ueda, Yoshinori, Hagiwara, Hiroko
• Primary Examiner(s): Winakur, Eric F
• Application Number:
  US14/557,806
• Publication Number:
  US 20150150513A1
• Time in Patent Office: 1,687 Days
• CPC Class Codes: A61B 2503/04 Babies, e.g. for SIDS detection
• CPC Class Codes: A61B 5/0205 Simultaneously evaluating both cardiovascular conditions and different types of body conditions, e.g. heart and respiratory condition
• CPC Class Codes: A61B 5/02416 using photoplethysmograph signals, e.g. generated by infrared radiation A61B5/14552 takes precedence
• CPC Class Codes: A61B 5/02427 Details of sensor
• CPC Class Codes: A61B 5/14551 for measuring blood gases
• CPC Class Codes: A61B 5/14552 Details of sensors specially adapted therefor
• CPC Class Codes: A61B 5/6826 Finger
• CPC Class Codes: A61B 5/6829 Foot or ankle
• CPC Class Codes: A61B 5/7203 for noise prevention, reduction or removal
• CPC Class Codes: A61B 5/7246 using correlation, e.g. template matching or determination of similarity
• CPC Class Codes: A61B 5/7278 Artificial waveform generation or derivation, e.g. synthesising signals from measured signals A61B5/327 takes precedence
• CPC Class Codes: A61B 5/7282 Event detection, e.g. detecting unique waveforms indicative of a medical condition A61B5/4094, A61B5/4818, A61B5/349, A61B5/0823 take precedence
• CPC Class Codes: A61B 5/742 using visual displays A61B5/339 takes precedence
• CPC Class Codes: A61B 5/746 Alarms related to a physiological condition, e.g. details of setting alarm thresholds or avoiding false alarms alarms per se G08B

Abstract

A biological signal measuring system includes: first and second optical sensors attached to first and second body portions of a subject; a first average oxygen saturation acquiring section acquiring a first average value corresponding to an average value of the first oxygen saturation corresponding to an arterial oxygen saturation in the first body portion in a predetermined time period starting at a first time; a second average oxygen saturation acquiring section acquiring a second average value corresponding to an average value of the second oxygen saturation corresponding to an arterial oxygen saturation in the second body portion in the predetermined time period starting at a second time that is different from the first time; and a difference value acquiring section acquiring a difference value, to be displayed, between the first average value and the second average value.

Claims

1. A biological signal measuring system comprising:

a first optical sensor which is to be attached to a first body portion of a subject;

a first attenuation ratio acquiring section which is configured to acquire a temporally changing first attenuation ratio corresponding to an attenuation ratio of a plurality of wavelengths in the first body portion, based on a first signal output from the first optical sensor;

a first oxygen saturation acquiring section which is configured to acquire a temporally changing first oxygen saturation corresponding to an arterial oxygen saturation in the first body portion, based on the temporally changing first attenuation ratio;

a second optical sensor which is to be attached to a second body portion of the subject;

a second attenuation ratio acquiring section which is configured to acquire a temporally changing second attenuation ratio corresponding to an attenuation ratio of a plurality of wavelengths in the second body portion, based on a second signal output from the second optical sensor;

a second oxygen saturation acquiring section which is configured to acquire a temporally changing second oxygen saturation corresponding to an arterial oxygen saturation in the second body portion, based on the temporally changing second attenuation ratio;

a first average oxygen saturation acquiring section which is configured to acquire a first average value corresponding to an average value of the first oxygen saturation in a predetermined time period starting at a first time;

a second average oxygen saturation acquiring section which is configured to acquire a second average value corresponding to an average value of the second oxygen saturation in the predetermined time period starting at a second time that is different from the first time;

a difference value acquiring section which is configured to acquire a difference value between the first average value and the second average value; and

a difference value displaying section which is configured to display the difference value.

2. The biological signal measuring system according to claim 1, further comprising:

a cross-correlation function acquiring section which is configured to acquire a cross-correlation function of the temporally changing first attenuation ratio and the temporally changing second attenuation ratio, or a cross-correlation function of the temporally changing first oxygen saturation and the temporally changing second oxygen saturation,

wherein the first time and the second time are determined based on the cross-correlation function.

3. The biological signal measuring system according to claim 1, further comprising:

a notifying section which, when the difference value is equal to or larger than a threshold, is configured to take a given notifying state.

4. The biological signal measuring system according to claim 3, wherein, when the first average value is smaller than a threshold, or when the second average value is smaller than the threshold, the notifying section is configured to take the given notifying state irrespective of the difference value.

5. The biological signal measuring system according to claim 1, further comprising:

a first average value displaying section which is configured to display the first average value; and

a second average value displaying section which is configured to display the second average value.

6. The biological signal measuring system according to claim 5, further comprising:

a first notifying section which, when the first average value is smaller than a threshold, is configured to take a given notifying state;

a second notifying section which, when the second average value is smaller than a threshold, is configured to take a given notifying state; and

a third notifying section which, when the difference value is equal to or larger than a threshold, is configured to take a given notifying state.

7. The biological signal measuring system according to claim 1, further comprising:

a heart rate acquiring section which is configured to acquire a heart rate of the subject based on at least one of the first signal and the second signal; and

a single heart rate displaying section which is configured to display the heart rate.

8. The biological signal measuring system according to claim 7, wherein the heart rate acquiring section is configured to select one of the first signal and the second signal which contains a smaller amount of noises, and acquire the heart rate based on the selected one of the first signal and the second signal.

9. The biological signal measuring system according to claim 7, wherein the heart rate acquiring section is configured to acquire, as the heart rate, and average value of:

the heart rate based on the first signal and the heart rate based on the second signal.