DE102004025042A1 - Device for determining the transit time of a blood pulse - Google Patents

Device for determining the transit time of a blood pulse

Info

Publication number
DE102004025042A1
DE102004025042A1 DE200410025042 DE102004025042A DE102004025042A1 DE 102004025042 A1 DE102004025042 A1 DE 102004025042A1 DE 200410025042 DE200410025042 DE 200410025042 DE 102004025042 A DE102004025042 A DE 102004025042A DE 102004025042 A1 DE102004025042 A1 DE 102004025042A1
Authority
DE
Germany
Prior art keywords
blood pulse
sensor
ir
characterized
location
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
DE200410025042
Other languages
German (de)
Inventor
Andreas Schoenfeld
Original Assignee
Schönfeld, Andreas, Dipl.-Ing.
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Schönfeld, Andreas, Dipl.-Ing. filed Critical Schönfeld, Andreas, Dipl.-Ing.
Priority to DE200410025042 priority Critical patent/DE102004025042A1/en
Publication of DE102004025042A1 publication Critical patent/DE102004025042A1/en
Application status is Withdrawn legal-status Critical

Links

Classifications

    • AHUMAN NECESSITIES
    • A61MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61BDIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B5/00Detecting, measuring or recording for diagnostic purposes; Identification of persons
    • A61B5/02Detecting, measuring or recording pulse, heart rate, blood pressure or blood flow; Combined pulse/heart-rate/blood pressure determination; Evaluating a cardiovascular condition not otherwise provided for, e.g. using combinations of techniques provided for in this group with electrocardiography or electroauscultation; Heart catheters for measuring blood pressure
    • A61B5/026Measuring blood flow
    • A61B5/0285Measuring or recording phase velocity of blood waves
    • AHUMAN NECESSITIES
    • A61MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61BDIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B5/00Detecting, measuring or recording for diagnostic purposes; Identification of persons
    • A61B5/02Detecting, measuring or recording pulse, heart rate, blood pressure or blood flow; Combined pulse/heart-rate/blood pressure determination; Evaluating a cardiovascular condition not otherwise provided for, e.g. using combinations of techniques provided for in this group with electrocardiography or electroauscultation; Heart catheters for measuring blood pressure
    • A61B5/021Measuring pressure in heart or blood vessels
    • A61B5/02108Measuring pressure in heart or blood vessels from analysis of pulse wave characteristics
    • A61B5/02125Measuring pressure in heart or blood vessels from analysis of pulse wave characteristics of pulse wave propagation time
    • AHUMAN NECESSITIES
    • A61MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61BDIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B5/00Detecting, measuring or recording for diagnostic purposes; Identification of persons
    • A61B5/02Detecting, measuring or recording pulse, heart rate, blood pressure or blood flow; Combined pulse/heart-rate/blood pressure determination; Evaluating a cardiovascular condition not otherwise provided for, e.g. using combinations of techniques provided for in this group with electrocardiography or electroauscultation; Heart catheters for measuring blood pressure
    • A61B5/024Detecting, measuring or recording pulse rate or heart rate
    • A61B5/02416Detecting, measuring or recording pulse rate or heart rate using photoplethysmograph signals, e.g. generated by infra-red radiation
    • A61B5/02427Details of sensor
    • A61B5/02433Details of sensor for infra-red radiation
    • AHUMAN NECESSITIES
    • A61MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61BDIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B5/00Detecting, measuring or recording for diagnostic purposes; Identification of persons
    • A61B5/04Measuring bioelectric signals of the body or parts thereof
    • A61B5/0402Electrocardiography, i.e. ECG
    • A61B5/0452Detecting specific parameters of the electrocardiograph cycle
    • A61B5/0456Detecting R peaks, e.g. for synchronising diagnostic apparatus
    • AHUMAN NECESSITIES
    • A61MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61BDIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B5/00Detecting, measuring or recording for diagnostic purposes; Identification of persons
    • A61B5/72Signal processing specially adapted for physiological signals or for diagnostic purposes
    • A61B5/7203Signal processing specially adapted for physiological signals or for diagnostic purposes for noise prevention, reduction or removal
    • A61B5/7207Signal processing specially adapted for physiological signals or for diagnostic purposes for noise prevention, reduction or removal of noise induced by motion artifacts
    • AHUMAN NECESSITIES
    • A61MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61BDIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B5/00Detecting, measuring or recording for diagnostic purposes; Identification of persons
    • A61B5/72Signal processing specially adapted for physiological signals or for diagnostic purposes
    • A61B5/7228Signal modulation applied to the input signal sent to patient or subject; demodulation to recover the physiological signal

Abstract

A device for determining the transit time of a blood pulse, comprising a first sensor 1 for detecting the blood pulse at a first location 1a and a second sensor for detecting the blood pulse at a second location 2a and having an evaluation unit 3 for forming the time difference between the occurrence of the Blood pulse at the first location 1a and the occurrence of the blood pulse at the second location 2a, is characterized in that at least the first sensor 1 at least one IR transmitter 11 and at least one IR receiver 14 has.

Description

  • The The invention relates to a device according to the preamble of the claim 1, for determining the duration of a blood pulse, with a first Sensor, for detecting the blood pulse at a first location, and a second sensor for detecting a blood pulse at a second Place, and with an evaluation unit to form the temporal Difference between the occurrence of the blood pulse at the first place and the occurrence of the blood pulse at the second location.
  • Such a device is for example from the EP 1 091 686 B1 known. In the known device, noises are recorded by means of a microphone, which are generated by the flow of a pulse of blood through the arteries. The sounds, like the blood flow, are pulsed. The duration of the blood pulse is determined by measuring the noise pulse at a first location, such as the carotid artery, and at a second location, such as an artery in the left foot area, and between the appearance of the blood pulse at the first location and the occurrence of the blood pulse at the second location forms the time difference. The duration of the blood pulse allows a conclusion about the elasticity of the arterial system.
  • Although such a determination of the elasticity of the arterial walls also gives very good results, so liable for this purpose Device nevertheless the disadvantage that they are very sensitive in terms on ambient conditions. In particular, ambient noise is extremely disturbing. Furthermore, the body's own effects Sounds such as hawking or noises by body movements arise, also very disturbing out. About that In addition, the pulses received by the known device have often a very unpronounced Rise to, whereby the impulse start often not with sufficient accuracy can be determined.
  • Out Angiology is a procedure for the diagnosis of arterial and venous vascular diseases known, by means of which the blood filling of arteries or veins is determined. For this purpose, by means of a light-emitting diode bundled light flashes of high intensity sent relatively deep into the tissue in the ultra-red spectral range. There they are scattered and reflected and finally by received a light receiver. amendments the blood filling cause different light densities, resulting in the detection of arterial Pulse curves and venous filling fluctuations allows because the absorption of hemoglobins and oxyhemoglobia especially high in the ultrarotic area. In a so-called Universal light reflex Plethysmografen is electronically the quotient from the through Pulsation or filling fluctuations causing light changes formed to the sent light amount. This is the individual Scattering be substantially downsized.
  • Of the There is no evidence to suggest that by means of the light-reflex plethysmography Pulse the duration of a Blood pulse can be determined.
  • It is the object of the invention, an initially mentioned device such to train them reliable and trouble-free is working.
  • The solution This object is apparent from the features of the characterizing Part of claim 1. Advantageous developments of the invention emerge from the dependent claims.
  • According to the invention is a device for determining the transit time of a blood pulse, with a first sensor, for detecting the blood pulse at a first Position, and a second sensor, for detecting the blood pulse a second place, and with an evaluation unit, for education the time difference between the occurrence of the blood pulse the first place and the occurrence of the blood pulse at the second Site, characterized in that at least the first sensor has at least one IR transmitter and at least one IR receiver.
  • Thereby, that at least the first sensor has at least one IR transmitter and at least one IR receiver, can be determined very well with the first sensor blood pulses. By using an infrared transmitter and an infrared receiver is the first sensor completely insensitive to noise. Also body movements have almost no effect. Thus, for example at a point where there is a microphone or other sensor can be easily inserted, a corresponding sensor can be used, and at a location where the use of a conventional Sensors problems, a sensor with an infrared transmitter and an infrared receiver be used.
  • Especially it is advantageous, however, if the second sensor at least an IR transmitter and at least one IR receiver. This will a very high reliability or immunity to interference reaches the device.
  • An embodiment of the invention has proven extremely advantageous in which the evaluation unit has a demodulator and the IR transmitter emits pulsed light and the corresponding signal emitted by the IR receiver is given to the demodulator. As a result, it is advantageously achieved that ambient conditions have virtually no influence on the measurement result. In particular, the device is thereby very susceptible to movement artefacts and fluctuations in the ambient light. Static reflections, as expected from different tissue structures, are easily averaged out by amplitude modulation.
  • Very advantageous in the embodiment described above it is when the demodulator emits a signal, if that from it demodulated signal begins to increase.
  • at another particular embodiment The invention provides that the time difference between measured respectively by the demodulators respectively emitted signals becomes and from several difference measured values an arithmetic Mean value is formed. This will reduce the accuracy of the device determined runtime value again significantly improved. Because by the formation of an average of several Einzelmeßwerten may be used for individual measurements existing disturbances, as well as physiological Leveled between successive heartbeats.
  • at another particular embodiment The invention provides that several IR transmitters available are. As a very advantageous, a sensor has been found in at which three IR transmitters are present, which on the circumference of a Are arranged circle, arranged in the middle of an IR receiver is. As a result, it is advantageously achieved that a larger area of the Tissue is illuminated with infrared light, thereby ensuring is that one enough large amount of light reflected by a blood pulse flowing through an artery becomes.
  • Further Details, features and advantages of the present invention result from the following description of a particular embodiment with reference to the drawing.
  • It shows
  • 1 a schematic representation of a device according to the invention,
  • 2 a sensor designed according to the invention,
  • 3 a signal output from an IR receiver,
  • 4 a signal output by a demodulator concerning a sensor located at a first location,
  • 5 a signal output from a demodulator concerning a sensor located at a second location, and
  • 6 a the in 3 to 5 associated signals associated ECG.
  • As 1 can be taken is with a human 7 at a first point located in the area of the carotid artery 1a a first sensor 1 arranged. Furthermore, a second sensor 2 on a second site located in the area of an artery 2a arranged. The first sensor 1 has a first infrared transmitting diode 11 and a first infrared receiver 14 on. The second sensor 2 has a second infrared transmitting diode 21 and a second infrared receiver 24 on. The first infrared transmitter diode 11 and the second infrared transmitting diode 21 be from a generator 4 supplied with a square wave signal of about ten kilohertz. The first infrared receiver 14 as well as the second infrared receiver 24 each receive the light reflected from the blood flowing through the respective arteries.
  • The corresponding to that of the first infrared transmitting diode 11 emitted rectangular light signal from the infrared receiver 14 of the first sensor 1 emitted signal whose waveform in 3 is shown on a first demodulator 15 given. The corresponding to that of the second infrared transmitting diode 21 emitted rectangular light signal from the second infrared receiver 24 of the second sensor 2 output signal is sent to a second demodulator 25 given. That from the first demodulator 15 demodulated signal whose waveform is in 4 is reproduced on a difference builder 5 given. The second demodulator 25 demodulated signal whose waveform is in 5 is reproduced, is also on the difference-builder 5 given. In the case of the demodulators 15 . 25 emitted signals is the envelope of the infrared receivers 14 . 24 emitted signals, which are then freed from an offset and thus easier to handle.
  • In the difference-builder 5 in each case the time difference (Δt) between the first demodulator 15 output signal and that of the second demodulator 25 emitted signal formed. The difference measured value (Δt) formed in each case is applied to a mean value generator 6 given, which forms an arithmetic mean of the obtained difference measured values (Δt). For this purpose, the sum of the difference measured values (.DELTA.t) is formed and by the Number of difference readings (n) divided.
  • Of the arithmetic mean is compared with a norm value which depends of the height, the Gender, age and other factors, such as a region-specific diet. By comparison with the standard value can be a statement about the Elasticity of the arterial system of the person concerned.
  • In a device 8th which is that of an electrode 8a captured heartbeats of the person 7 an electrocardiogram (ECG) is recorded. The beginning of a heart action is on the subtractor 5 given. In the subtractor 5 are those of the demodulators 15 . 25 Checked signals for plausibility and, if no plausibility is given, excluded from the evaluation.
  • As 2 can be removed, the sensor points 1 ( 2 ) three IR transmitter diodes 11 . 12 . 13 ( 21 . 22 . 23 ), which are arranged on the circumference of a circle K. The center M of the circle K is an infrared receiving diode 14 ( 24 ) arranged. The light emitted by such an arrangement illuminates the tissue very well, so that a relevant artery is transilluminated with a relatively high intensity of light. As a result, a great deal of the light reflected from the blood flowing through the artery reaches the infrared receiver 14 ( 24 ). The arrangement has the advantage that the sensor does not have to be positioned very accurately.
  • There every blood pulse is the effect of a single heartbeat it is of particular advantage if the associated ECG is recorded and the temporal allocation of the blood pulse curves respectively the beginning of a heart action is related.
  • As in 6 is shown, the determination of the R-wave (R) in the ECG, the earliest onset of a blood pulse curve can be determined. The R wave (R) in the ECG represents the beginning of the ejection phase of the left ventricle, after which the blood pulse signal in the carotid can be detected after a very short period of time. Advantageously, it can be determined by the temporal assignment of the blood pulse curves to the beginning of a heartbeat when determining the pulse transit time between the carotid and left foot, for example, whether no extrasystoles of the heart take place during the transit time. Since this could lead to a superimposition of the individual signals, it can be ensured by reference to the beginning of a heartbeat that only regular pulse transit times are taken into account in the evaluation.

Claims (8)

  1. Device for determining the transit time of a blood pulse, comprising a first sensor ( 1 ), for detecting the blood pulse at a first location ( 1a ), and a second sensor ( 2 ), for detecting the blood pulse at a second location ( 2a ), and with an evaluation unit ( 3 ), for forming the time difference between the occurrence of the blood pulse at the first location ( 1a ) and the occurrence of the blood pulse at the second location ( 2a ), characterized in that at least the first sensor ( 1 ) at least one IR transmitter ( 11 ) and at least one IR receiver ( 14 ) having.
  2. Apparatus according to claim 1, characterized in that the second sensor ( 2 ) at least one IR transmitter ( 21 ) and at least one IR receiver ( 24 ) having.
  3. Apparatus according to claim 1 or 2, characterized in that the evaluation unit ( 3 ) a demodulator ( 15 . 25 ) and the IR transmitter ( 11 . 21 ) emits a pulsed IR light and that from the IR receiver ( 14 . 24 ) delivered corresponding signal to the demodulator ( 15 . 25 ) is given.
  4. Device according to Claim 3, characterized in that the demodulator ( 15 . 25 ) emits a signal when the signal demodulated by it reaches a threshold value (must still be precisely defined).
  5. Apparatus according to claim 4, characterized in that the time difference between the demodulators ( 15 . 25 ) respectively emitted signals and an arithmetic mean value is formed from a plurality of differential measured values ( 5 ).
  6. Device according to one of Claims 1 to 5, characterized in that a plurality of IR transmitters ( 11 . 12 . 13 . 21 . 22 . 23 ) available.
  7. Apparatus according to claim 6, characterized in that three IR transmitters ( 11 . 12 . 13 . 21 . 22 . 23 ), which are arranged on the circumference (K) of a circle in the middle (M) of the IR receiver ( 14 . 24 ) is arranged.
  8. Device according to one of claims 1 to 7, characterized in that an element ( 8th ) is present for detecting the heartbeat.
DE200410025042 2004-05-18 2004-05-18 Device for determining the transit time of a blood pulse Withdrawn DE102004025042A1 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
DE200410025042 DE102004025042A1 (en) 2004-05-18 2004-05-18 Device for determining the transit time of a blood pulse

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
DE200410025042 DE102004025042A1 (en) 2004-05-18 2004-05-18 Device for determining the transit time of a blood pulse
PCT/DE2005/000929 WO2005110212A1 (en) 2004-05-18 2005-05-18 Device for determination of the duration of a heartbeat
DE200511001783 DE112005001783A5 (en) 2004-05-18 2005-05-18 Device for determining the transit time of a blood pulse

Publications (1)

Publication Number Publication Date
DE102004025042A1 true DE102004025042A1 (en) 2005-12-29

Family

ID=34972413

Family Applications (2)

Application Number Title Priority Date Filing Date
DE200410025042 Withdrawn DE102004025042A1 (en) 2004-05-18 2004-05-18 Device for determining the transit time of a blood pulse
DE200511001783 Pending DE112005001783A5 (en) 2004-05-18 2005-05-18 Device for determining the transit time of a blood pulse

Family Applications After (1)

Application Number Title Priority Date Filing Date
DE200511001783 Pending DE112005001783A5 (en) 2004-05-18 2005-05-18 Device for determining the transit time of a blood pulse

Country Status (2)

Country Link
DE (2) DE102004025042A1 (en)
WO (1) WO2005110212A1 (en)

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE3533912A1 (en) * 1985-09-23 1987-04-02 Schmid Walter Sphygmomanometer
EP0467853B1 (en) * 1990-07-18 1996-01-10 AVL Medical Instruments AG Device and method for the measurement of blood pressure
EP1091686B1 (en) * 1998-09-09 2003-05-21 Helen Marcoyannopoulou Fojas Device of determining the elasticity of the arterial wall

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE3533912A1 (en) * 1985-09-23 1987-04-02 Schmid Walter Sphygmomanometer
EP0467853B1 (en) * 1990-07-18 1996-01-10 AVL Medical Instruments AG Device and method for the measurement of blood pressure
EP1091686B1 (en) * 1998-09-09 2003-05-21 Helen Marcoyannopoulou Fojas Device of determining the elasticity of the arterial wall

Also Published As

Publication number Publication date
WO2005110212A1 (en) 2005-11-24
DE112005001783A5 (en) 2007-05-31

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Legal Events

Date Code Title Description
OP8 Request for examination as to paragraph 44 patent law
8143 Withdrawn due to claiming internal priority