EP2627245A2 - Dispositif portable pour le diagnostic précoce d'une cardiopathie et/ou de maladies cardiovasculaires qui peuvent être déterminées par des variables hémodynamiques - Google Patents

Dispositif portable pour le diagnostic précoce d'une cardiopathie et/ou de maladies cardiovasculaires qui peuvent être déterminées par des variables hémodynamiques

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Publication number
EP2627245A2
EP2627245A2 EP11813343.8A EP11813343A EP2627245A2 EP 2627245 A2 EP2627245 A2 EP 2627245A2 EP 11813343 A EP11813343 A EP 11813343A EP 2627245 A2 EP2627245 A2 EP 2627245A2
Authority
EP
European Patent Office
Prior art keywords
bioimpedance
time
frequency
signals
patient
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Withdrawn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
EP11813343.8A
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German (de)
English (en)
Inventor
Ferdinando De Negri
Pietro Valdastri
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Winmedical Srl
Original Assignee
Winmedical Srl
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Filing date
Publication date
Application filed by Winmedical Srl filed Critical Winmedical Srl
Publication of EP2627245A2 publication Critical patent/EP2627245A2/fr
Withdrawn legal-status Critical Current

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Classifications

    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B5/00—Measuring for diagnostic purposes; Identification of persons
    • A61B5/05—Detecting, measuring or recording for diagnosis by means of electric currents or magnetic fields; Measuring using microwaves or radio waves 
    • A61B5/053—Measuring electrical impedance or conductance of a portion of the body
    • A61B5/0537—Measuring body composition by impedance, e.g. tissue hydration or fat content
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B5/00—Measuring for diagnostic purposes; Identification of persons
    • A61B5/02—Detecting, 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
    • A61B5/02028—Determining haemodynamic parameters not otherwise provided for, e.g. cardiac contractility or left ventricular ejection fraction
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B5/00—Measuring for diagnostic purposes; Identification of persons
    • A61B5/05—Detecting, measuring or recording for diagnosis by means of electric currents or magnetic fields; Measuring using microwaves or radio waves 
    • A61B5/053—Measuring electrical impedance or conductance of a portion of the body
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B2560/00—Constructional details of operational features of apparatus; Accessories for medical measuring apparatus
    • A61B2560/04—Constructional details of apparatus
    • A61B2560/0443—Modular apparatus
    • A61B2560/045—Modular apparatus with a separable interface unit, e.g. for communication
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B5/00—Measuring for diagnostic purposes; Identification of persons
    • A61B5/0002—Remote monitoring of patients using telemetry, e.g. transmission of vital signals via a communication network
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B5/00—Measuring for diagnostic purposes; Identification of persons
    • A61B5/68—Arrangements of detecting, measuring or recording means, e.g. sensors, in relation to patient
    • A61B5/6801—Arrangements of detecting, measuring or recording means, e.g. sensors, in relation to patient specially adapted to be attached to or worn on the body surface
    • A61B5/6813—Specially adapted to be attached to a specific body part
    • A61B5/6823—Trunk, e.g., chest, back, abdomen, hip
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B5/00—Measuring for diagnostic purposes; Identification of persons
    • A61B5/68—Arrangements of detecting, measuring or recording means, e.g. sensors, in relation to patient
    • A61B5/6801—Arrangements of detecting, measuring or recording means, e.g. sensors, in relation to patient specially adapted to be attached to or worn on the body surface
    • A61B5/683—Means for maintaining contact with the body
    • A61B5/6831—Straps, bands or harnesses

Definitions

  • the present invention relates to medical devices and, in particular, it relates to a wearable device for cardiopathy or cardiovascular diagnosis in a patient and/or for detecting hemodynamic variables.
  • the device is used for diagnosis of cardiopathies, for example cardiac decompensation, or for measuring hemodynamic useful for diagnosis of such pathologies.
  • cardiovascular diseases in particular cardiopathies such as cardiac decompensation, can be correlated to accumulation of fluids/liquids in the body, to their flow and to their variation with time.
  • the prevention and the early diagnosis of such cardiopathies is carried out by detecting any serious hydro-electrolytic alterations that can cause the diseases such as, for example, anasarca, declive edema, acute pulmonary edema etc.
  • Impedance Z This opposition to the current is called Impedance Z and is based on the principle that the current follows a path of minimum electric resistance.
  • Such value of impedance Z can be represented by a complex number, and therefore formed by a real and an imaginary part, or also by a module and by a phase. More precisely, the current flows through the fluids, in particular water, and, the opposition to the current can be correlated (inversely proportional) to the volume of water in the body. In other words, a higher amount of liquid determines a lower value of the bioimpedance module and vice-versa.
  • the value of the bioimpedance module monitored in previous days to the occurrence of the symptoms is decreasing progressively up to reaching a minimum value where the disease becomes symptomatic.
  • the known devices for measuring the bioimpedance inject the current at a single frequency, and are not for this reason adapted to provide a reliable monitoring.
  • the variation of the bioimpedance determined at a single frequency is not strictly correlable to the variation of the fluids caused by a worsening of the cardiac function, because it can be also correlated to other parameters of the patient same.
  • by at least one bioimpedance measurement at fixed frequency it is not possible to discriminate precisely between intra or extra cellular liquids. It is therefore difficult to determine the causes of the variation of the impedance, both of its module and of its phase.
  • Such alteration and its amount for example, can be generated by a variation of the fat mass of the patient and influenced by other physical factors such as sex, weight, age or even daily habits.
  • the known devices based on the bioimpedance measurement are not adapted to obtain a functional monitoring of the patient for a long time.
  • the known bioimpedance measurement devices there are bulky and expensive ones. For this reason, often, such diagnosis has to be limited to hospitals or nursing homes, causing a long monitoring to be problematic, which would be instead much easier with laptop devices .
  • the known bioimpedance measuring systems in particular those that can determine the onset of cardiopathies, can be problematic and do not allow to obtain reliable values of changes of the body fluids, especially in a wireless monitoring scenario. For this reason, values observed by such measuring devices should be always associated and backed by other types of detection and analysis devices.
  • ICG impedance Cardiography
  • thoracic bioimpedenziometry or impedance pletismography relates to the study of the cardiac functionality by measuring the electric impedance of the thorax.
  • the variation of impedance, determined through electrodes applied to the thorax, is generated by fluctuations in the volume of blood and in the blood speed, mainly with respect to the rising aorta tract, during the cardiac cycle.
  • the known ICG devices provide monitoring the patient in a hospital to measure the thoracic impedance from which different hemodynamic variables can be measured in a predetermined moment of a day. For long monitoring periods, the patient must every day make a measurement, in order to obtain, after a plurality of measurements, a clinic picture enough complete for a diagnosis of the cardiac diseases.
  • the use of wearable ICG devices to long daily monitoring for more days are very unreliable.
  • the measure can be strongly affected by factors such as the arrangement of the electrodes, the movement of the patient, the variation of the interface conditions of the skin with the electrodes, etc.
  • O2004/030535 a method is described for measuring the volume, the composition and the movement (HZV) of electro- conductive body fluids, based on the Impedance Cardiography (ICG) for determining hemodynamic parameters.
  • ICG Impedance Cardiography
  • an implantable device comprising electrodes implantable in the patient's body capable of making current signals at different frequencies in order to calculate impedance values.
  • the implanted electrodes are not subject to problems of variability owing to the interface with the skin of the user, but it is an invasive device.
  • diagnostic unit mounted to said wearable support, said diagnostic unit comprising:
  • a memory that is configured to store said plurality of complex bioimpedance signals ⁇ , Z 2 , Z 3 ... Z n at a first time ti, at a second time t 2 and at an nth time t n ;
  • an alarm means to provide an alarm of cardiac decompensation associated with said means for analysing, said alarm generated if said decrease value DR/Dt is higher than a predetermined value DRo/Dt.
  • said means for analysing comprises a sampling means that is configured to operate said means for delivering and said means for measuring in a predetermined time range, in order to repeat a plurality of said bioimpedance measurements at times ti, t 2 ,...t n that are distant said time range from each other.
  • said sampling time range is one day, and said number n of times ti, t 2 ,...t n is set between 7 and 30 days, preferably 14 days.
  • said means for analysing is configured to compare said time chart of the real part Ri, R 2 , R3 ... R n of the complex bioimpedance signals determined on the patient also with characteristic time charts of a cardiopathy by means of clinical data of said patient, in order to increase the amount of data to compare and to obtain a more precise prediction, in particular said clinical data describing the health status of the patient and being selected from the group consisting of: age, sex, weight, fat-free mass index, etc.
  • said means to provide an alarm comprises an acoustic emitter.
  • said complex bioimpedance signals ⁇ , Z 2 , Z 3 ... Z n are calculated as average values within a predetermined measurement range, in particular set between 3 and 10 minutes.
  • said means for delivering an electric stimulus is adapted to deliver a current stimulus and comprises:
  • variable current frequency generator connected to said skin injection electrodes and associated with said adjustment means that adjust said current stimulus, such that said adjustment means controls in frequency said current generator such that it injects said plurality of electric stimuli at respective different frequencies, said current having a corresponding predetermined digital numerical series.
  • said different frequencies fi, f 2 ,...f n are comprised in a range set between 1 kHz and a lMHz and said electric stimuli have an intensity set between 0.1mA and 0.5mA, in particular 0.44mA.
  • said means for measuring comprises:
  • - a means for calculating the bioimpedance module as ratio between the absolute values of said digital numerical series responsive to said voltage and of said digital numerical series responsive to said current stimulus at a predetermined frequency fi, in order to obtain a corresponding digital numerical signal of the bioimpedance module;
  • the couple of skin sensor electrodes measure a voltage V fX tuned to the current stimulus I fl at frequency f x .
  • the module of the bioelectric impedance signal Z fi can be obtained relative to frequency fi.
  • the modules of the bioimpedance signals Z fli Z f2 , Z f3 , ...Z fn are obtained.
  • a time chart can thus be generated of such complex values, i.e. of the bioimpedance module and phase, comparable with charts/complex patterns typical of the onset of cardiopathies.
  • said means for determining the module and the phase of each of said complex bioimpedance signals comprises a amplifier a band-pass filter.
  • said means for analysing comprises:
  • said programmable logic unit is associated with said sampling means, with said means for delivering and with said means for measuring, in order to select a predetermined frequency fi of said electric stimulus, for generating and analysing said plurality of complex bioimpedance signals, in particular the modulus and phase signals at said different frequencies fi , f 2 ,...f n , in a way to generate said time chart and compare it with a time chart typical of a cardiopathy present in said memory.
  • This way it is possible to evaluate the evolution with time of said complex bioimpedance signals measured at the different frequencies. It is then possible to recognize and compare the trend obtained for the patient with other trends, determined with the same technique, which describe a time chart feature that resembles the typical onset of cardiopathies.
  • bioimpedance signals obtained with multifrequency measurements of a patient for a period of more days are computed in order to obtain for each day a characteristic chart that describes the trend of such complex values, for example within one day.
  • Each daily chart will then added to other data, in order to obtain a set of charts that as a time chart, for example a weekly chart.
  • the chart is compared by a comparison means with further bioimpedance charts that describe a trend typical of the onset of a cardiopathy.
  • said means for comparing can compare said trend of the patient with the characteristic trend.
  • the comparison can be investigated further also on the basis of the clinical data of the patient, for example the fat mass index, age, sex, weight etc., making it possible to obtain a even higher reliability and then a more precise and accurate preliminary diagnosis.
  • said means for analysing is further configured to extract from the complex bioimpedance signal, cardiovascular hemodynamic functionality signals like the cardiac output (volume-minute) , the cardiac index, the stroke volume, the system vascular resistance, the flow acceleration index, the flow velocity index, the thoracic fluid content, the cardiac work, the pre-ejection time and ventricular ejection time etc.
  • said hemodynamic signals are obtained from a sampling at high frequency, for example 200 samples per second for a predetermined time.
  • the means for analysing comprises a plurality of known algorithms for analysing the bioelectric impedance signal and to turn it into one of the above cited hemodynamic signals.
  • the algorithms applicable to the bioimpedance module and phase signals, taken at different frequencies are configured to determine the set of the above described hemodynamic variables for each signal at different frequencies.
  • the comparison and by the control of the values of the hemodynamic variables measured on the signals at the different frequencies is possible to determine the hemodynamic parameters of the patient in a way reliable and supported by numerical verification.
  • the obtained data can discriminate possible artifacts due to the fact that the device is wearable and used directly by the end user. For example, if some hemodynamic variables obtained to determine frequencies have values higher or less than determined thresholds, the system can communicate for example an positioning error of the electrodes by an alarm.
  • said means for analysing is configured to compare said cardiovascular hemodynamic functionality signals with said time chart to obtain a more reliable prediction of said cardiopathy.
  • said couple of injection electrodes and said couple of sensor electrodes are substantially arranged in line,, in particular they can be associated with a belt' or other wearable element. This way, the relative position of the electrodes remains fixed, in order to reduce the artifacts of the measure due to a wrong or inaccurate positioning.
  • said device further comprises an interface means that is configured to transfer the collected and computed data to a central collection and correlation unit which can correlate it with other signals.
  • said interface means is a wireless or wired interface means.
  • said interface means comprises a coupling means that is arranged to provide a matching shape with said central collection unit.
  • the wearable device can monitor the patient for a long period, for example 24h. For example, the patient can wear the device during a whole day during which more bioimpedance signals are determined and recorded for eventually generating a time chart, for example in a several days time. Such chart, can then be compared with a known trend of known bioimpedance values in case of a cardiopathy, which allows an early diagnosis thereof and then permits to adopt preventive measures.
  • said interface means can be used for combining the device with other sensor devices and modules, such as an accelerometer, an electrocardiograph, a device for pulse oximetry that measures the concentration of oxygen in the blood, a module for measuring the pressure, the temperature etc.
  • sensor devices and modules such as an accelerometer, an electrocardiograph, a device for pulse oximetry that measures the concentration of oxygen in the blood, a module for measuring the pressure, the temperature etc.
  • FIG. 1 shows a diagrammatical view of a wearable device for early diagnosis of cardiopathies, according to the invention
  • - Fig. 2 shows a diagrammatical view of the wearable device of Fig. 1 mounted to the thorax of a patient
  • - Fig. 3 shows a block diagram that diagrammatically shows the steps of measuring the bioimpedance phase versus the current frequency
  • FIG. 3A shows in particular the step of control and comparison of the data of bioimpedance, in order to obtain a time chart of such values for deriving an early diagnosis on the onset of cardiac diseases, such as a cardiac decompensation;
  • Figs. 4 and 5 show a trend of the data of variable frequency bioimpedance obtained from the measurements made by the device of Fig. 1;
  • Fig. 6 shows a diagrammatical view of the control of each complex signal of bioimpedance, in order to obtain the chart of Figs. 4 and 5;
  • Fig. 7 shows a further application of the device of Fig. 1 that is configured to extract hemodynamic parameters of the patient from the complex bioimpedance signals;
  • FIG. 8 shows a perspective view of the device according to the invention mounted to a belt wearable by a patient.
  • a diagrammatical view is shown a device 100 of early diagnosis of cardiopathies in a patient 50 (Fig.2), such as a cardiac decompensation and/or cardiovascular diseases which can be determined by detecting hemodynamic variables.
  • the patient 50 has determined clinical data that describe the health status, which are then combined with the measurements obtained from the device 100, as described below.
  • the diagnostic device 100 comprises a wearable support 1 on which a diagnostic unit 5 is arranged that comprises a means for delivering 10 an electric stimulus, in particular a electric current stimulus Ii, at a predetermined frequency fi, to the patient's body 50, at the thorax 55.
  • the diagnostic unit 5 comprises a means for measuring 20 a thoracic electrical bioimpedance Zi applied always on the patient's body for providing a bioelectric impedance signal Z on the basis of the electric stimulus Ii at a predetermined frequency fi.
  • the diagnostic device 100 also comprises, as also shown in Fig. 3, an adjustment means 30 for adjusting the frequency fi of the electric stimulus Ii, included in the means for generating 10, such that a plurality of electric stimuli Ii, I 2 , I3 ... I n can be imparted at respective different frequencies f , f 2 , f 3 ...
  • the means 20 for measuring the thoracic electrical bioimpedance detects a corresponding complex bioimpedance signal Zi, Z 2 Z 3 , Z n for each plurality of electric stimuli ⁇ , I 2 , I3 - In at respective different frequencies fi, f 2 , f 3 - fn -
  • a plurality of complex bioimpedance signals Z lf Z 2 , Z 3 ... Z n it is possible to obtain a plurality of complex bioimpedance signals Z lf Z 2 , Z 3 ... Z n .
  • the device for early diagnosis comprises a memory 35 that is configured to store the plurality of complex bioimpedance signals at a first time ti, at a second time t 2 and at an nth time t n , and a means for extracting the real part R x , R 2 , R 3 ... R n of said complex bioimpedance signals Z lf Z 2 , Z 3 ... Z n recorded in said memory 35, respectively at said first time ti, second time t 2 and nth time t n , to obtain a respective time chart Ci, C 2 , C n of said real part for each frequency f lr f 2 ,...f n at the times
  • the sampling time range is one day, and the number n of said times t x , t 2 ,...t n is set between 7 and 30 days, preferably 14 days.
  • the device has a means for analysing 40 the time chart Ci, C 2 , C n (Fig. 4 and 5) of the real part Rii 2 , R3 - Rn/ in order to obtain a decrease rate with time of the real part for each frequency f lr f 2 ,...f n and to calculate a decrease value DR/Dt.
  • device 100 has a means 40 for analysing the time chart of the complex bioimpedance signals Z i , Z 2 , Z n , in order to obtain a decrease rate with time of the complex signals of impedance Z i , Z 2 , Z n for each frequency fx, f 2 ,...f n and for calculating a decrease value.
  • a means 46 is provided to provide an alarm of cardiac decompensation, said alarm generated if said decrease value DR/Dt is higher than a predetermined value DR 0 /Dt, as described below more in detail.
  • the means for analysing 40 is configured to compare the time chart or data resulting from the real part of the complex bioimpedance signals Z i , Z 2 , Z 3 ... Z n determined on the patient 50, with respect to a trend/data chart of a cardiopathy monitored in a previous time, in order to achieve an early check on the onset of said cardiopathy.
  • the complex bioimpedance signals ⁇ , Z 2 , Z 3 ... Z n are calculated as average values within a predetermined measurement range, in particular set between 3 and 10 minutes .
  • a means can be provided for extracting the imaginary part Li, L 2 , L 3 ... L n of the complex bioimpedance signals ⁇ , Z 2 , Z 3 ... Z n to obtain a respective time chart of said imaginary part for each frequency fi, f 2 ,...f n at the times ti, t 2 ,...t n ;
  • the means for analysing (40) compute in this case the time chart of the imaginary part Li, L 2 , L 3 ... L n , in order to obtain a rate of variation with time of the imaginary part for each frequency f x , f 2 ,...f n and to calculate a variation value DL/Dt.
  • a means is provided to provide a parameter of cardiac decompensation associated with the means for analysing 40 if the variation value DL/Dt exceeds the limits by a predetermined range.
  • the means for analysing 40 associated with the memory 35 comprises a programmable logic unit 45.
  • the programmable logic unit 45 is associated in turn to the means for delivering 10 and to the means for measuring 20, in order to select a predetermined frequency fi of the electric stimulus I f i to deliver, and to analyse the corresponding bioimpedance signals Z f i, in particular the signals of module
  • the use of more currents at different frequencies allows to discard changes of the bioimpedance values that are anomalous and not directly connected to an accumulation of liquid that is characteristic of a potential cardiopathy, but are due to other causes, for example to habits of the patient.
  • the charts of the real part of the bioimpedance obtained for each current and frequency are computed through a comparison block 55 that has as input the data measured on the patient 50 in different previous instant/daily measurements. Furthermore, also characteristic data can be compared on the basis of the clinical data of patient 50.
  • the cardiac decompensation has a low sampling frequency, about a sample per day, i.e. a daily value of bioimpedance daily.
  • a daily value for example a value per second is acquired for a time of 5 min and then the collected data are computed, in order to obtain a single average value, as above described.
  • Fig. 4 depicts the bioimpedance module, or real part, versus the frequency for days 1, 2.. N. In This way, it is possible to observe the trend of variation of this quantity in more days.
  • the graphs thus obtained are compared, by the means for comparing, with further bioimpedance charts that describe a typical trend of the onset of a cardiopathy, not shown.
  • the means for comparing 55 compare the trend of the patient with the trend of the previous days ti, t ⁇ , t n as well as with known data that are obtained from the clinical data of the patient 50.
  • the comparison can be investigated also on the basis of such patient's clinical data which comprise for example fat mass index, age, sex, weight etc., to obtain a even higher reliability and then a more precise and accurate preliminary diagnosis.
  • a cardiac decompensation or other cardiac diseases can be diagnosed in advance with respect to the consequent diseases, in order to prevent them with appropriate therapies carried out on patient 50 under strict monitoring.
  • said means for analysing 40 comprises a sampling means 25 that is configured to operate the means for delivering 10 and the means for measuring 20 in a predetermined time range, in order to repeat a plurality of measurements at times ti, t 2 , t n that are distant by said time range from each other.
  • the means for delivering 10 the electric stimulus comprises a couple of skin injection electrodes
  • variable frequency electric generator 10 connected to the skin injection electrodes 11/12 and associated with the means 30 for adjusting the current stimulus. More precisely, the electric stimuli Ii,
  • variable frequency voltage generator V(f) that represents the adjustment means 30.
  • the variable frequency voltage thus obtained is then converted into the respective currents Ii, I 2 , I3 ... I n at respective different frequencies f l r f 2 , f 3 ... f n by a block 31.
  • the frequencies fi, f 2 ,...f n are comprised in a range set between 1 kHz and a lMHz and said electric stimuli have an intensity set between 0.1mA and 0.5mA, in particular 0.44mA.
  • the means for measuring 20 comprises a couple of skin sensor electrodes 21, 22 arranged substantially between the couple of injection electrodes 11, 12, as shown in Fig. 2, configured to measure a voltage V fi tuned to the plurality of electric stimuli Ii at respective different frequencies fi and a means for calculating 27 the module
  • the means for measuring 20 comprises a means 29 for calculating the phase PPi of the bioimpedance as phase shift time At between the voltage V fi and the current stimulus Ii at a predetermined frequency fi, in order to obtain a corresponding signal Pi of the bioimpedance phase.
  • a means 29a for converting the signal of the phase PPi of the bioimpedance into a respective digital numerical signal is provided.
  • the couple of skin sensor electrodes 21, 22 measure a voltage V f i tuned to the current stimulus Ifi at frequency fi.
  • the module of the bioelectric impedance signal Z f i relative to frequency fi can be obtained. Changing the frequency of the current I for a predetermined frequency band the modules of the bioimpedance signals Z f i, Z f2 , Z f3 , ... Z fn are obtained.
  • the injected current signal I f i is compared with the measured voltage signal V f i taking into account the delay time At ⁇ .
  • the current Ii is generated starting from a predetermined digital numerical series, then turned into analog signal by a digital-analog converter, and eventually transformed from voltage to current which is supplied to injection electrodes 11, 12.
  • sensor electrodes 21, 22 detect a corresponding voltage that passes through a filter and then through a signal amplifier and eventually through a digital-analog converter for making a corresponding voltage digital signal.
  • the bioimpedance module is obtained by combining the digital signals of current Ii and of voltage Vj.. To obtain the phase P the phase shift time is measured between the analog signal of the injected current and the analog signal relative to the measured voltage. Such phase shift, which is the bioimpedance phase, is then encoded into a digital signal for assisting the computing steps.
  • the steps of computing the module and the phase of each complex bioimpedance signal Zi are made, as shown in Fig. 6, by means of respective analog and/or digital demodulator electronic circuits 27/29, among which a divider block for the module and a phase detector for the phase, from which the respective digital signals of the module Z and of the phase Pi exit as output.
  • the means for calculating the module and the phase comprises, furthermore, a signal amplifier 28 and a band pass filter 26 accordable in frequency.
  • Such a multifrequency measurement of the bioimpedance is used, furthermore, to obtain hemodynamic signals, i.e. data on cardiac parameters that can be compared and combined with the monitoring results obtained as above described.
  • hemodynamic signals are obtained from a higher sampling frequency, for example 200 samples per second for a time of 1 minute, and from a computing step, by means of known algorithms of curves representing said signals (Fig. and 5).
  • the sampling i.e. detecting the plurality of complex signals, on both module and phase, of the bioimpedance, and the parameters from it obtained, are in this case instantaneous.
  • the means for analysing 40 comprises a plurality of known algorithms for extracting, from the bioimpedance complex signal, cardiovascular hemodynamic functionality signals, like the cardiac output (volume- minute) , the cardiac index, the stroke volume, the system vascular resistance, the flow acceleration index, the flow velocity index, the thoracic fluid content, the cardiac work, the pre-ejection time and ventricular ejection time etc.
  • said means for analysing 40 is configured to compare the cardiovascular hemodynamic functionality signals with the time chart of the bioimpedance measurement, to obtain a more reliable prediction of said cardiopathy.
  • the above described parameters are calculated not on the basis of a signal detected at a single frequency, but on the basis of a plurality of signals measured at different frequencies.
  • the multifrequency device allows instead a practical usage that enables the patient 50 a simple and direct application of the device same.
  • a peculiar element of device 100 with respect to the known devices consists of applying such algorithms not only to a bioelectric impedance signal (bioimpedance module) acquired at a predetermined frequency, but also of applying them to a plurality of signals taken at different frequencies. This way a set of values of the hemodynamic variables is generated for each frequency of the stimulation signal. By comparing and computing such numerical set reliable values of the hemodynamic variables of the patient are obtained, even with a wearable device.
  • the multifrequency monitoring allows, in fact, to generate for example a positioning error signal of the electrodes and then to warn the patient that an alarm threshold has been exceeded.
  • hemodynamic signals are obtained responsive to the frequency fj . .
  • hemodynamic signals can be further computed and integrated on the basis of the clinical data of the same patient 50 to obtain a realistic and reliable value.
  • the couple of injection electrodes 11, 12 and the couple of sensor electrodes 21, 22 are substantially arranged in line, in particular they can be associated with a belt or other wearable element 60. This way, the relative position of the electrodes remains fixed, in order to reduce the artifacts of the measurement due to a wrong or inaccurate positioning.
  • the device further comprises an interface means that is configured to transfer the collected and computed data to a central collection and correlation unit which can correlate it with other signals.
  • the interface means is for example a wireless or wired interface or, alternatively, a coupling means that is arranged to provide a matching shape with the central collection unit 200, as shown in Fig. 8.
  • a wireless interface or an interface with matching shape device 100 is wearable and is configured to monitor the patient 50 for a long period, for example 24h or for more days.
  • the interface means can be used for combining device 100 with other sensor devices and modules such as an accelerometer, an electrocardiograph, a device for pulse oximetry that measures the oxygen concentration in the blood, a module for measuring the pressure, the temperature etc.

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  • Radiology & Medical Imaging (AREA)
  • Cardiology (AREA)
  • Physiology (AREA)
  • Measurement And Recording Of Electrical Phenomena And Electrical Characteristics Of The Living Body (AREA)
  • Measuring Pulse, Heart Rate, Blood Pressure Or Blood Flow (AREA)

Abstract

L'invention porte sur un dispositif de diagnostic précoce (100) de cardiopathies chez un patient (50), telles qu'une décompensation cardiaque et/ou des maladies cardiovasculaires, lequel dispositif comprend un support (1) portable et une unité de diagnostic (5) montée sur le support (1) portable. L'unité de diagnostic (5) comprend un moyen pour l'administration (10) d'un stimulus de courant électrique (Ii), à une fréquence prédéterminée (fi) au corps (50) du patient et un moyen pour la mesure (20) d'une bioimpédance électrique thoracique (Zi), qui est conçu pour fournir un signal d'impédance bioélectrique (Zi) sur la base du stimulus électrique (Ii) à la fréquence prédéterminée (fi). Le dispositif (100) comprend en outre un moyen d'ajustement (300) pour l'ajustement de la fréquence (fi) du stimulis électriques (Ii) d'une manière appropriée pour transmettre une pluralité de stimuli électriques (I1, I2, …, In) à différentes fréquences respectives (f1, f2, f3, …, fn) et de sorte que le moyen de mesure (20) détecte un signal de bioimpédance complexe correspondant (Z1, Z2, Z3, Zn). En outre, le dispositif comprend une mémoire (35) qui est configurée pour stocker les signaux de bioimpédance complexes à un premier instant (ti), à un deuxième instant (t2) et un n-ième instant (tn) et un moyen pour l'extraction de la partie réelle (R1, R2, R3, …, Rn) des signaux complexes pour les instants (t1,t2, tn), afin d'obtenir un graphique chronologique (C1, C2, Cn) respectif de la partie réelle pour chaque fréquence. En outre, le dispositif comprend un moyen pour l'analyse (40) du graphique chronologique (C1, C2, Cn) et un moyen pour fournir une alarme (46) de décompensation cardiaque si une valeur de diminution DR/Dt est supérieure à une valeur prédéterminée DRo/Dt.
EP11813343.8A 2010-10-11 2011-10-11 Dispositif portable pour le diagnostic précoce d'une cardiopathie et/ou de maladies cardiovasculaires qui peuvent être déterminées par des variables hémodynamiques Withdrawn EP2627245A2 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
ITPI2010A000116A IT1402105B1 (it) 2010-10-11 2010-10-11 Dispositivo indossabile per la diagnosi di patologie cardiache e/o per la rilevazione di variabili emodinamiche.
PCT/IB2011/002386 WO2012049552A2 (fr) 2010-10-11 2011-10-11 Dispositif portable pour le diagnostic précoce d'une cardiopathie et/ou de maladies cardiovasculaires qui peuvent être déterminées par des variables hémodynamiques

Publications (1)

Publication Number Publication Date
EP2627245A2 true EP2627245A2 (fr) 2013-08-21

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EP11813343.8A Withdrawn EP2627245A2 (fr) 2010-10-11 2011-10-11 Dispositif portable pour le diagnostic précoce d'une cardiopathie et/ou de maladies cardiovasculaires qui peuvent être déterminées par des variables hémodynamiques

Country Status (3)

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EP (1) EP2627245A2 (fr)
IT (1) IT1402105B1 (fr)
WO (1) WO2012049552A2 (fr)

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CN109846464A (zh) * 2018-12-29 2019-06-07 曹乃钊 血液流动力学参数的无创测量系统和数据处理系统
CN112155546B (zh) * 2020-09-22 2024-06-28 芯海科技（深圳）股份有限公司 肺功能检测设备及计算机可读取存储介质
NO20201071A1 (en) * 2020-09-30 2022-03-31 Mode Sensors As Tissue fluid measurement device
CN117243585B (zh) * 2023-11-10 2024-04-16 深圳市奋达智能技术有限公司 无创心排量测量方法、系统、计算机设备及存储介质

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AT413189B (de) * 2002-10-07 2005-12-15 Cnsystems Medizintechnik Gmbh Medizinisches elektroden-element
US7447543B2 (en) * 2005-02-15 2008-11-04 Regents Of The University Of Minnesota Pathology assessment with impedance measurements using convergent bioelectric lead fields
WO2010104952A2 (fr) * 2009-03-10 2010-09-16 Corventis, Inc. Systèmes d'affichage pour dispositifs de surveillance de santé portés sur le corps

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Also Published As

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WO2012049552A3 (fr) 2012-06-21
ITPI20100116A1 (it) 2012-04-12
IT1402105B1 (it) 2013-08-28
WO2012049552A2 (fr) 2012-04-19

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