Heartbeat synchronous information acquiring apparatus and pulse wave propagation velocity related information acquiring apparatus, blood pressure monitoring apparatus and preejection period measuring apparatus utilizing heartbeat synchronous information

• US 20030032887A1
• Filed: 08/09/2001
• Published: 02/13/2003
• Est. Priority Date: 08/09/2001
• Status: Active Grant

• Current Assignee: Omron Healthcare Company Limited (Omron Corporation)
• Original Assignee: Colin Corporation (Fukuda Denshi Company Limited)
• Inventors: Harada, Chikao, Kawaguchi, Keizoh, Narimatsu, Kiyoyuki, Yokozeki, Akihiro
• Granted Patent: US 6,748,262 B2
• Time in Patent Office: Days
• US Class Current: 600/513
• CPC Class Codes: A61B 5/02125 of pulse wave propagation time
• CPC Class Codes: A61B 5/02225 using the oscillometric method
• CPC Class Codes: A61B 5/02416 using photoplethysmograph signals, e.g. generated by infrared radiation A61B5/14552 takes precedence
• CPC Class Codes: A61B 5/0535 Impedance plethysmography for measuring blood flow A61B5/0295

Abstract

The gate means 73 extracts the partial impedance pulse wave SM_IMP(P) from the thorax impedance pulse wave SM_IMP detected by the thorax impedance pulse wave detector 64. This is done over an intake period defined as a period starting from a first time T₁ after the time when the R wave of the induced electro-cardiac wave is detected to the time when a rising edge of the photoelectric pulse wave SM₂ is detected. Then, the heartbeat synchronous information determining means 74 selects a rising edge of the partial impedance pulse wave SM_IMP(P) that periodically appears as heartbeat synchronous information I_H. Thus, it is possible to accurately determine the heartbeat synchronous information I_H. Additionally, since the photoelectric pulse wave SM₂ that is detected by the photoelectric pulse wave sensor 40 is largely free of noise it is possible to accurately determine the end of the period for reading the thorax impedance pulse wave SM_IMP.

Claims

1. A heartbeat synchronous information acquiring apparatus provided with an impedance pulse wave detector for detecting an impedance pulse wave of a living body containing heartbeat synchronous components between a pair of electrodes fitted to predetermined positions of the living body with a heart interposed therebetween in order to acquire the heartbeat synchronous information generated synchronously with heartbeats of the living body based on the impedance pulse wave, said apparatus comprising:

an induced electro-cardiac wave detection device for continuously detecting an induced electro-cardiac wave of said living body;

gate means for extracting a partial impedance pulse wave from the impedance pulse wave by taking in the impedance pulse wave for an intake period based on the time of detection of a predetermined part of the induced electro-cardiac wave by the induced electro-cardiac wave detection device; and

heartbeat synchronous information determining means for determining a periodically appearing predetermined part of the partial impedance pulse wave extracted by the gate means as heartbeat synchronous information.

2. The heartbeat synchronous information acquiring apparatus according to claim 1, wherein

said intake period of said gate means is from the end of a predetermined first time period starting from the time of detection of the predetermined part of the induced electro-cardiac wave by the induced electro-cardiac wave detection device to the end of a predetermined second time period starting from the time of detection of the predetermined part, said second time period being longer than said first time period.

3. A heartbeat synchronous information acquiring apparatus according to claim 1, further comprising a photoelectric pulse wave sensor for detecting a photoelectric pulse wave at a part irradiated with light, said sensor being provided with a light source for irradiating a skin of said living body with light, and a photo detector for detecting transmitted or reflected light originating from said light source,

the intake period of said gate means being from the end of a first time period starting from the time of detection of the predetermined part of the induced electro-cardiac wave by the induced electro-cardiac wave detection device to the time of detection of the predetermined part of the photoelectric pulse wave by said photoelectric pulse wave sensor.

4. A blood pressure monitoring apparatus for monitoring a blood pressure of a living body, said apparatus comprising:

blood pressure measuring means for measuring a blood pressure of the living body by using a cuff for pressing an artery of the living body;

an induced electro-cardiac wave detection device for continuously detecting an induced electro-cardiac wave of said living body;

an impedance pulse wave detector for detecting an impedance pulse wave of said living body containing heartbeat synchronous components between a pair of electrodes fitted to predetermined positions of the living body with a heart interposed therebetween;

gate means for extracting a partial impedance pulse wave from the impedance pulse wave by taking in the impedance pulse wave for an intake period based on the time of detection of a predetermined part of the induced electro-cardiac wave by the induced electro-cardiac wave detection device;

a pulse wave detector fitted to a part of said living body for detecting a pulse wave propagating through the artery of said living body;

pulse wave propagation velocity related information computing means for continuously computing information on the pulse wave propagation velocity based on said partial impedance pulse wave and said pulse wave propagating through the artery of said living body;

propagation velocity related information versus blood pressure relationship determining means for determining a corresponding relationship between the propagation velocity related information computed by said pulse wave propagation velocity related information computing means and the blood pressure measured by said blood pressure measuring means at each time of such measurement of said blood pressure by said blood pressure measuring means; and

monitored blood pressure determining means for continually determining a value of a monitored blood pressure from the corresponding relationship between the propagation velocity related information and the blood pressure as determined by said propagation velocity related information versus blood pressure relationship determining means based on the actual pulse wave propagation velocity related information computed by said pulse wave propagation velocity related information computing means.

5. The blood pressure monitoring apparatus according to claim 4, further comprising a monitored blood pressure abnormality judging means for judging normality or abnormality of the value of the monitored blood pressure as determined by said monitored blood pressure determining means by referring to a predetermined judgment reference range and starting the operation of said blood pressure measuring means when the value of the monitored blood pressure is judged to be an abnormal value.

8. The blood pressure monitoring apparatus according to any one of claims 4 through 7, wherein

said intake period of said gate means is from the end of a predetermined first time period starting from the time of detection of the predetermined part of the induced electro-cardiac wave by the induced electro-cardiac wave detection device to the end of a predetermined second time period starting from the time of detection of the predetermined part, said second time period being longer than said first time period.

9. The blood pressure monitoring apparatus according to any one of claims 4 through 7, wherein

the pulse wave detector includes a photoelectric pulse wave sensor for detecting a photoelectric pulse wave at a part irradiated with light, said sensor being provided with a light source for irradiating a skin of said living body with light, and a photo detector for detecting transmitted or reflected light originating from said light source,

the intake period of said gate means being from the end of a first time period starting from the time of detection of the predetermined part of the induced electro-cardiac wave by the induced electro-cardiac wave detection device to the time of detection of the predetermined part of the photoelectric pulse wave by the photoelectric pulse wave sensor.

6. A blood pressure monitoring apparatus provided with a blood pressure measuring means for measuring a blood pressure of a living body by shifting a pressure of a cuff fitted to and pressing against the living body in a predetermined cycle based on a pulse synchronous wave generated in a process of shifting the pressure pressing against the living body, said apparatus comprising:

an induced electro-cardiac wave detection device for continuously detecting an induced electro-cardiac wave of said living body;

an impedance pulse wave detector for detecting an impedance pulse wave of a living body containing heartbeat synchronous components between a pair of electrodes fitted to predetermined positions of the living body with a heart interposed therebetween;

gate means for extracting a partial impedance pulse wave from the impedance pulse wave by taking in the impedance pulse wave for an intake period based on the time of detection of a predetermined part of the induced electro-cardiac wave by the electro-cardiac wave detection device;

a pulse wave detector fitted to a part of said living body for detecting a pulse wave propagating through an artery of said living body;

pulse wave propagation velocity related information computing means for consecutively computing information on the pulse wave propagation velocity based on said partial impedance pulse wave and said pulse wave propagating through the artery of said living body; and

monitored blood pressure change judging means for judging a change in a blood pressure of said living body based on any change in the pulse wave propagation velocity related information continually computed by said pulse wave propagation velocity related information computing means exceeding a predetermined judgment reference value.

7. The blood pressure monitoring apparatus according to claim 6, wherein

said monitored blood pressure change judging means is adapted to trigger the operation of said blood pressure measuring means when it judges a change in the blood pressure of the living body.

10. A pulse wave propagation velocity related information acquiring apparatus for acquiring information relating to a propagation velocity of a pulse wave propagating through an artery of a living body, said apparatus comprising:

an induced electro-cardiac wave detection device for continuously detecting an induced electro-cardiac wave of said living body;

an impedance pulse wave detector for detecting an impedance pulse wave of the living body containing heartbeat synchronous components between a pair of electrodes fitted to predetermined respective positions of the living body with a heart interposed therebetween;

gate means for extracting a partial impedance pulse wave from the impedance pulse wave by taking in the impedance pulse wave for an intake period as determined based on the time of detection of a predetermined part of the induced electro-cardiac wave by the induced electro-cardiac wave detection device;

a pulse wave detector fitted to a part of said living body for detecting the pulse wave propagating through the artery of said living body; and

pulse wave propagation velocity related information computing means for computing information on a velocity of the pulse wave propagating through the living body based on the time difference obtained by subtracting a second time difference from a first time difference, said first time difference being computed as the time difference between a time a predetermined part in the induced electro-cardiac wave by the induced electro-cardiac wave detection device periodically appears and a time a predetermined part in the pulse wave detected by said pulse wave detector periodically appears, said second time difference being computed as the time difference between a time said predetermined part in the induced electro-cardiac wave periodically appears and a time a predetermined part in the partial impedance pulse wave extracted by said gate means periodically appears.

11. The pulse wave propagation velocity related information acquiring apparatus according to claim 10, wherein

said pulse wave detector comprises a cuff to be wound around said living body and a cuff pulse wave discriminating circuit for extracting a cuff pulse wave that is a pressurized vibration of the cuff.

12. The pulse wave propagation velocity related information acquiring apparatus according to claim 10, wherein

said pulse wave detector comprises a pressure pulse wave sensor for detecting a pressure pulse wave that is generated in the artery of the living body as the artery is pressed via the skin of the living body.

13. The pulse wave propagation velocity related information acquiring apparatus according to claim 10, wherein

said pulse wave detector comprises a photoelectric pulse wave sensor including a light source for irradiating a skin of the living body with light and a photo detector for detecting transmitted or reflected light originating from said light source.

15. The pulse wave propagation velocity related information acquiring apparatus according to any one of claims 10 through 14, wherein

said intake period of said gate means is from the end of the predetermined first time period starting from the time of detection of the predetermined part of the induced electro-cardiac wave by the induced electro-cardiac wave detection device to the end of the predetermined second time period starting from the time of detection of the predetermined part, said second time period being longer than said first time period.

16. The pulse wave propagation velocity related information acquiring apparatus according to claim 13, wherein

said intake period of said gate means is from the end of a predetermined first time period starting from the time of detection of the predetermined part of the induced electro-cardiac wave by the induced electro-cardiac wave detection device to the detection of the predetermined part of the photoelectric pulse wave by said photoelectric pulse wave sensor.

14. A pulse wave propagation velocity related information acquiring apparatus for acquiring information relating to a propagation velocity of a pulse wave propagating through an artery of a living body, said apparatus comprising:

an induced electro-cardiac wave detection device for continuously detecting an induced electro-cardiac wave of said living body;

an impedance pulse wave detector for detecting an impedance pulse wave of the living body containing heartbeat synchronous components between a pair of electrodes fitted to predetermined positions of the living body with a heart interposed therebetween;

gate means for extracting a partial impedance pulse wave from the impedance pulse wave by taking in the impedance pulse wave for an intake period based on the time of detection of a predetermined part of the induced electro-cardiac wave by the induced electro-cardiac wave detection device;

a pulse wave detector fitted to a part of said living body for detecting the pulse wave propagating through the artery of said living body; and

pulse wave propagation velocity related information computing means for computing information on the velocity of the pulse wave propagating through the living body based on the time difference between a time a predetermined part in the partial impedance pulse wave extracted by said gate means periodically appears and a time a predetermined part in the pulse wave detected by said pulse wave detector periodically appears.

17. A preejection period measuring apparatus for measuring a preejection period from start of a contraction of a heart of a living body to a time when blood is ejected out from the heart by heartbeat, said apparatus comprising:

an induced electro-cardiac wave detection device for detecting an induced electro-cardiac wave of said living body;

an impedance pulse wave detector for detecting an impedance pulse wave of the living body containing heartbeat synchronous components between a pair of electrodes fitted to predetermined positions of the living body with the heart interposed therebetween;

gate means for extracting a partial impedance pulse wave from the impedance pulse wave by taking in the impedance pulse wave for an intake period based on the time of detection of a predetermined part of the induced electro-cardiac wave by the induced electro-cardiac wave detection device;

a pulse wave detector fitted to a part of said living body for detecting a pulse wave propagating through an artery of said living body; and

preejection period computing means for computing the preejection period by subtracting a second time difference from a first time difference, said first time difference being computed as the time difference between a time a predetermined part in the induced electro-cardiac wave detected by said induced electro-cardiac wave detection device periodically appears and a time a predetermined part in the pulse wave detected by said pulse wave detector periodically appears, said second time difference being computed as the time difference between a time said predetermined part in the partial impedance pulse wave extracted by said gate means periodically appears and a time said predetermined part in the pulse wave detected by said pulse wave detector periodically appears.

19. The preejection period measuring apparatus according to claim 17 or 18, further comprising cardiac function assessing means for assessing a cardiac function of the living body based on the preejection period computed by said preejection period computing means.

20. The preejection period measuring apparatus according to any one of claims 17 through 19, wherein

said intake period of said gate means is from the end of a predetermined first time period starting from the time of detection of the predetermined part of the induced electro-cardiac wave by the induced electro-cardiac wave detection device to the end of a predetermined second time period starting from the time of detection of the predetermined part, said second time period being longer than said first time period.

18. The preejection period measuring apparatus for measuring a preejection period from start of a contraction of a heart of a living body to a time when blood is ejected out from the heart by heartbeat, said apparatus comprising:

an electro-cardiac wave detection device for detecting an induced electro-cardiac wave of said living body;

an impedance pulse wave detector for detecting an impedance pulse wave of the living body between a pair of electrodes fitted to predetermined positions of the living body with the heart interposed therebetween;

gate means for extracting a partial impedance pulse wave from the impedance pulse wave by taking in the impedance pulse wave for an intake period based on the time of detection of a predetermined part of the induced electro-cardiac wave by the induced electro-cardiac wave detection device; and

preejection period computing means for computing the preejection period as time difference between a time a predetermined part in the induced electro-cardiac wave detected by said induced electro-cardiac wave detection device periodically appears and a time a predetermined part in the partial impedance pulse wave extracted by said gate means periodically appears.