Medical device for monitoring biological parameters

Abstract

A medical device (10) for monitoring a user's biological parameters comprises the following: · a plate (1) for measuring the user's mass, · at least first and second electrodes (11, 12, 21, 22) for performing impedance measurements, · a device (23) for measuring blood pressure and / or heart rate.

Description

Technical Field

[0001] The present invention relates to a medical device for monitoring biological parameters.

Background Art

[0002] Daily monitoring of water and salt (phosphorus, calcium, potassium, sodium chloride) intake is very important for patients suffering from chronic kidney disease. Specifically, poor management of such intake is harmful to the ability of patients to withstand dialysis (especially by causing hypotension and / or cramps during dialysis), and significantly increases the likelihood of developing side effects associated with diseases such as hypertension and / or cardiovascular problems.

[0003] Particularly with regard to water and salt, only by high levels of intake restriction can patients with chronic kidney disease live with their disease. Therefore, it is of utmost importance to regularly, and especially daily, provide patients with means for monitoring the intake of those food-derived liquids, thereby enabling patients to improve their tolerance to dialysis and reduce the risk of developing side effects of dialysis.

[0004] In the current situation, daily monitoring of water intake is empirically and easily carried out by comparing the measured body weight with a reference weight called the "ideal weight" of the patient. The reference weight of the patient corresponds to an estimated weight that the patient should normally achieve at the end of a dialysis session when all excess fluid has been removed, and is therefore also called the "dry weight". The dry weight of a dialysis patient is generally determined empirically by the care team as the lowest weight that the patient can tolerate without any undesirable effects on the patient. This is a compromise point that is reexamined by consultation among relatively observable clinical symptoms, the history of intolerance during dialysis, and the measured body weight and blood pressure. Therefore, in most cases, the dry weight is estimated by an iterative approach, and the estimation error of the dry weight can be detected by either the occurrence of undesirable effects during the dialysis session (when the dry weight is underestimated) or the onset of symptoms of fluid retention (when the dry weight is overestimated).

[0005] Evaluation of body composition makes it possible to distinguish between the water mass and the total mass, and thus to determine a more reliable dry weight for reference in managing the amount of fluid absorbed by the patient between two dialysis sessions, and thus to determine the volume of water to be removed during a dialysis session.

[0006] In addition, daily home monitoring of indicators related to the side effects of the disease enables improvement in the response time when actively responding to these side effects, especially when actively responding to hypertension and cardiovascular problems. Summary of the Invention

[0007] Currently, there are devices that enable the evaluation of body composition, especially in the home environment. However, these devices are generally unsuitable for the body composition and physical activity levels of patients presenting with chronic kidney disease, considering that the median age of patients treated by dialysis is 71 years, and that the disease is almost systematically associated with many co-morbidities. In addition, existing devices do not take into account the specific needs of these patients, such as the need to detect and monitor the side effects of the disease.

[0008] Furthermore, various devices for measuring the body composition of patients treated by dialysis produce significantly different results depending on the device used. For this reason, it is impossible to compare the measurements resulting from different devices for the same patient. As a result, it is impossible to monitor patients based on data from different devices.

[0009] The object of the present invention is to overcome the above-mentioned drawbacks and to provide a device for monitoring biological parameters that improves on the devices known from the prior art.

[0010] In particular, the object of the present invention is to manufacture a device that is simple and reliable and enables the daily monitoring of the patient's weight and / or the amount of body fluid absorbed between two dialysis sessions, and / or the daily monitoring of the side effects of chronic kidney disease.

[0011] For this purpose, the present invention relates to a medical device for monitoring the biological parameters of a user, the device comprising: · a plate for measuring the weight of the user; · at least first and second electrodes for performing impedance measurements; · a device for measuring blood pressure and / or heart rate.

[0012] In one embodiment, the device for measuring blood pressure and / or heart rate is a photoplethysmograph sensor that can also measure the oxygen saturation of the user's blood.

[0013] In one embodiment, the plate comprises a first electrode capable of measuring impedance at one of the user's feet, and the second electrode is arranged to be able to measure impedance at the user's first hand.

[0014] In one embodiment, the medical device comprises a third electrode arranged in contact with the user's second hand, and the second and third electrodes can record an electrocardiogram between the user's first hand and second hand together.

[0015] In one embodiment, the medical device comprises a temperature sensor that enables measurement of the user's skin temperature.

[0016] In one embodiment, the medical device comprises means for adjusting the height of the second electrode relative to the plate to adapt the vertical distance measured between the second electrode and the plate to the height of the user.

[0017] In one embodiment, the medical device comprises a first handgrip, the second electrode is fixed on the first handgrip, arranged on a rigid arm substantially parallel to the plate, and the adjustable means is a system for adjusting the height of the rigid arm including the first handgrip relative to the plate to enable adjustment of the height of the first handgrip relative to the plate.

[0018] In one embodiment, the electrodes of the medical device inject a current having an intensity of 8 - 200 μA, or 8 - 150 μA, or 8 - 100 μA, or about 32 μA, including an increase or decrease of 10%, and are suitable for measuring the impedance of the user's foot or hand by frequency sweeping from 125 Hz to 500 kHz, or up to 800 kHz, or up to 4 kHz to 300 kHz.

[0019] In one embodiment, the medical device comprises an electronic processing unit. Electrodes and / or a device for measuring blood pressure and / or heart rate, and / or a temperature sensor are connected to the electronic processing unit by a wired or wireless communication device, such that impedance measurements obtained using the electrodes can be transmitted to the electronic processing unit, and the electronic processing unit can control the current transmitted to the user's hand or foot by the electrodes.

[0020] In one embodiment, the medical device comprises hardware elements and / or software elements configured to perform the following processing operations: · Measuring the total mass of the user; · Measuring the foot-to-hand impedance; · Measuring the volume of intracellular water contained in the user's body; · Measuring the volume of extracellular water contained in the user's body; · Measuring the total volume of water contained in the user's body; · Measuring the dry weight; · Measuring the excess water volume; · Optionally, measuring the change in dry weight; · Optionally, measuring the change in excess water; · Optionally, measuring blood pressure; · Optionally, measuring the pulse wave; · Optionally, measuring the heart rate; · Optionally, measuring the blood oxygen saturation; · Optionally, measuring the hand-to-hand electrocardiogram; · Optionally, measuring the skin temperature.

[0021] In one embodiment, the measurement of the volume of intracellular water, the measurement of the volume of extracellular water, and the measurement of the total volume of water are performed independently of each other.

[0022] In one embodiment, the medical device comprises a human-machine interface that enables the display of at least one data item selected from the following: · The total mass of the user, · The total amount of water contained in the user's body, · The dry weight of the user, · The variation in the dry weight of the user, · The amount of excess water, · The variation in the amount of excess water, · The heart rate of the user, · The blood pressure of the user, · The skin temperature of the user, · The visual display of bioimpedance.

[0023] The accompanying drawings show, by way of example, one embodiment of a monitoring device according to the present invention.

Brief Description of the Drawings

[0024]

Figure 1

Figure 2

Figure 3

Modes for Carrying Out the Invention

[0025] An example of a system for monitoring biological parameters equipped with a monitoring device according to the present invention will be described below with reference to FIGS. 1 to 3.

[0026] In the remainder of this specification, the term "weight" should be understood to mean mass measured in kilograms.

[0027] The medical monitoring system 100 mainly comprises the following elements: · At least one medical monitoring device 10, · A distributed network infrastructure 20, ·At least one terminal 30 for medical experts.

[0028] The distributed network infrastructure 20 includes a network 201, a central memory 202 that houses a database 203, and a program for processing data included in the database. The central memory also houses a program for managing communication between each control unit 3 of at least one medical monitoring device 10 and a user terminal 30 assigned to a medical expert.

[0029] Such an embodiment using a distributed architecture allows the simplest calculations to be directly executed in the medical device 10 and more complex calculations to be delegated to a computer server connected to the database 203.

[0030] In a minimal embodiment, the medical monitoring system 100 can be composed of just one medical device 10. All calculations are performed locally, i.e., within the medical device 10.

[0031] In the remainder of this specification, the medical monitoring device 10 is also referred to as the "medical device 10" or the "device 10".

[0032] The medical device 10, particularly shown in FIG. 2, comprises the following: · A plate 1 for measuring the user's weight, · At least first and second electrodes 11, 12, 21, 22 for performing impedance measurements at at least two different frequencies and for measuring at least the amount of water in the user's body, · A device 23 for measuring blood pressure and / or heart rate.

[0033] The volume of water measured by the first and second electrodes 11, 12, 21, 22 is the volume of intracellular water, the volume of extracellular water, and the total volume of water. These measurements will be described later.

[0034] The characteristics of the current injected into the electrodes for impedance measurement, particularly the frequency characteristics, will be described in detail later in this specification. The device uses at least two different current frequencies, namely, a first frequency for measuring the volume of extracellular water in the body and a second frequency higher than the first frequency for measuring the total volume of water in the body. Advantageously, the frequency sweep of the current injected into the electrodes includes at least two, or three frequencies (at least a low frequency and / or a medium frequency, and a high frequency), or at least six frequencies, or at least twelve frequencies. The high frequency means a frequency higher than 50 kHz. The low frequency means a frequency less than 5 kHz. The medium frequency means a frequency between 5 and 50 kHz.

[0035] In one embodiment, the plate 1 comprises at least one load cell 13 for measuring the total mass of the user. Advantageously, the plate comprises several load cells 13, for example four load cells 13, in order to optimize the accuracy with which the total mass of the user is measured.

[0036] In one embodiment, the plate 1 comprises first electrodes 11, 12 capable of measuring impedance at one of the user's feet. Further, the second electrodes 21, 22 are arranged so as to be able to measure impedance at the user's first hand.

[0037] Accordingly, both the first and second electrodes can measure the impedance between the user's foot and hand, in particular, the impedance between the foot and hand on the same side of the user's body, that is, the impedance between the foot and hand located on the same half of the user's body. Preferably, the measurement is carried out on the right half of the body in order to limit the extent to which the cardiac operation interferes with the impedance measurement.

[0038] In the remainder of this specification, the impedance measurement between the user's foot and hand is referred to as a "foot-hand impedance measurement".

[0039] Note that what is meant by impedance measurement is any direct and indirect measurement that enables obtaining such parameters directly, such as voltage measurement, voltage fluctuations as a function of time, current and / or current fluctuations as a function of time, or their derivatives.

[0040] More generally, in the remainder of the document, the term "measurement" may refer to data generated directly from a sensor and / or data calculated from data collected from a sensor. The calculation can include algorithmic calculations, especially calculations involving learning algorithms, such as neural network learning calculations.

[0041] Furthermore, the term "foot" can include the foot, especially the sole of the foot, the top of the foot, and the toes, and can also be used to indicate a body part extending above the ankle. Similarly, the term "hand" can include the hand, especially the palm of the hand, the back of the hand, and the fingers, and can also be used to indicate a body part extending above the wrist.

[0042] Plate 1 may be provided with two or more electrodes, for example two electrodes 11, 12, arranged to contact simultaneously with the feet of a user standing upright on the plate. For example, one electrode 11 may contact the heel of the foot and the other electrode 12 may contact the front of the foot. In the remainder of this specification, the term "first electrode" refers to one or more electrodes arranged on plate 1. The first electrode is intended to measure the impedance between one of the user's feet and another region of the user's body.

[0043] In addition, or alternatively, at least two electrodes 21, 22 may be arranged on the user's first hand. For example, one electrode 21 may contact the palm of the first hand and the other electrode 22 may contact the fingers of the first hand. In the remainder of this specification, the term "second electrode" refers to one or more electrodes arranged in contact with the user's first hand and intended to perform measurements with the user's first hand.

[0044] Accordingly, depending on the number of electrodes included within the medical device 10, the first and second electrodes may be capable of performing different types of impedance measurements between the user's foot and the first hand, such as bipolar measurements, tripolar measurements, or quadripolar measurements.

[0045] The medical device 10 further comprises a device 23 for measuring blood pressure and / or heart rate.

[0046] In one embodiment, the device for measuring blood pressure and / or heart rate is a photoplethysmograph sensor 23.

[0047] The photoplethysmograph sensor 23 can acquire all or some of the measured values of the user's blood pressure, heart rate, and blood oxygen saturation.

[0048] The photoplethysmograph sensor 23 can include an array of at least two light-emitting LEDs and one or two receiving photodiodes. The at least two light-emitting LEDs generate light at two different wavelengths, and the respective wavelengths of these LEDs are, for example, 500 - 750 nm in the first case and 850 - 1000 nm in the second case.

[0049] As another embodiment of the device 23 for measuring blood pressure, for example, a blood pressure cuff can be considered.

[0050] The medical device may further comprise a third electrode 41 disposed in contact with the user's second hand. In the remainder of this specification, the term "third electrode" refers to one or more electrodes disposed in contact with the user's second hand and intended to perform measurements with the user's second hand.

[0051] The second and third electrodes 21, 22, 41 together can record an electrocardiogram between the user's first hand and second hand.

[0052] In the remainder of this specification, the impedance measurement value between the user's first hand and second hand is referred to as the "hand-to-hand impedance measurement value".

[0053] Also, the second and third electrodes 21, 22, 41 can together perform the following: · Measuring the heart rhythm, and / or · Measuring the pulse wave traveling between the second and third electrodes 21, 22, 41, and / or · Measuring the velocity of the pulse wave traveling between the second and third electrodes 21, 22, 41.

[0054] The medical device may further include a temperature sensor 24 that enables measurement of the user's skin temperature.

[0055] Advantageously, the medical device comprises means for adjusting the height of the second electrodes 21, 22 relative to the plate 1 so as to adapt the vertical distance measured between the second electrode and the plate to the user's height. Thus, the second electrodes 21, 22 may be arranged in such a way as to conform to the natural position of the hand in which they are placed in contact.

[0056] The adjustment means can take various forms. For example, in one preferred embodiment, the device 10 may comprise a first handgrip 2 to which the second electrodes 21, 22 are fixed. In this case, the adjustment means can be a system for adjusting the height of the first handgrip 2 relative to the plate 1.

[0057] The medical device 10 may further comprise a second handgrip 4 provided with a third electrode 41. The adjustment means can also adjust the height of the second handgrip relative to the plate 1.

[0058] Accordingly, according to an embodiment, the medical device comprises a plate for receiving a user's foot and two handgrips for receiving the user's hand or arm respectively. Advantageously, these handgrips are rigid and are arranged on two rigid arms, as will be described in detail later.

[0059] A device 23 for measuring blood pressure and / or heart rate, and / or a temperature sensor 24 may be arranged on the first or second handgrip 2, 4.

[0060] The medical device 10 further comprises in particular an electronic processing unit 3 as shown in FIG. 3. This unit incorporates at least one computer 30 and a connection 32 enabling the connection of the computer 30 to the sensors 13, 23, 24 and the electrodes 11, 12, 21, 22, 41 of the medical device 10. Thus, the computer 30 can receive data measured by the sensors. The electronic processing unit 3 further comprises a medium or an electronic memory 31 for recording data. The electronic processing unit 3 also comprises a power supply 34 connected to all or some of the electrodes, thereby enabling a current to be injected through the electrodes. The electronic processing unit 3 further comprises at least one voltage sensor 36 capable of collecting physiological data via the measurement electrodes. This voltage sensor 36 may alternatively be arranged remotely on the measurement electrodes or within the electronic processing unit 3 as shown. Finally, the electronic processing unit 3 comprises for example a communication device 35 enabling the transmission of electronic data such as body composition measurements or blood pressure to the outside and / or the reception of data from the outside such as setup data or messages sent by medical experts. The electronic memory 31 also enables the storage of measurements and / or data calculated locally in the medical device 10. The measurements and / or data calculated locally in the medical device 10 are then transmitted to the database 203 via the network 20. It is advantageous for the measurements and / or data calculated locally in the medical device 10 to be stored in the memory 31 for a minimum period of time, particularly when the network 20 is not available. The minimum length of time for which the data is stored may be for example 15 days.

[0061] The data in the electronic memory 31 can be read by the computer 30 or by any other computing device of the electronic processing unit 3, on which a computer program for operating the medical device 10 is recorded, in particular a computer program for performing the measurement and calculation of the biological parameters described in the remainder of this specification.

[0062] In one embodiment shown in FIG. 2, the medical device 10 includes a plate 1 and a support 6 connected to the first and second handgrips 2, 4. The support 6 includes a vertical post 60 fixed to the plate 1 at its lower part. The vertical post 60 is preferably perpendicular to the plate 1. The vertical post 60 is positioned in such a way that the user can step onto the plate 1 and place one foot simultaneously on two electrodes 11, 12 of the plate.

[0063] The support 6 also includes a U-shaped frame composed of three parallelepiped parts 61, 62, 63 joined to each other, and a central part 63 is disposed between two parts 61, 62 that form two branches of the U. In one embodiment, the parts 61, 62, 63 are rigidly joined to each other, and the assembly they form extends in a substantially horizontal plane, i.e., a plane parallel to the plane of the plate 1. Alternatively, the parts forming the branches 61, 62 can rotate around the central part 63. The branch 61 includes a first end connected to the central part 63 and a second end connected to the first handgrip 2. The branch 62 includes a first end connected to the central part 63 and a second end connected to the second handgrip 4. The central part 63 is fixed perpendicular to the vertical post 60 in the upper region of the vertical post 60. In an advantageous embodiment, the fixing between the vertical post 60 and the central part 63 includes means for adjusting the height of the U-shaped frame. The height adjustment of the U-shaped frame makes it possible to adjust the height of the handgrips 2, 4, i.e., the vertical distance separating the handgrips 2, 4 from the plate 1.

[0064] According to one embodiment, the two branches 61, 62 of the medical device 10 take the form of two rigid arms.

[0065] The two branches 61, 62 include electrodes intended to cooperate with the user's hand via, for example, the handgrip 2.

[0066] As a modification, the rigid frame arranged at the height of the hand so as to cooperate with the user's hand may have a shape other than U-shaped.

[0067] In addition, the height adjustment means may include a lock / unlock device that enables the two branch portions 61 and 62 to be fixed or not fixed to the support 6, thereby enabling them to be maintained at the selected height. This lock / unlock device can also unlock this position, so that it can be moved and its height can be adjusted. For this purpose, the guide device can move the guide device, for example, using at least one guide rail, especially for vertical translational movement. The support 6 can slide, for example, to translate vertically to adjust it, and then can be maintained at the selected height by a mechanism including specific openings of the support and pins inserted into the vertical posts corresponding to the selected height of the support.

[0068] Therefore, the device ensures that the electrodes are adjusted to the correct height for cooperation with the user's hand, and then ensures that this height is kept constant during regular, for example, daily measurements, for optimal mutual consistency between various measurements.

[0069] The vertical post and / or the U-shaped frame are preferably hollow so that they can incorporate the sensors 11, 12, 13, 21, 22, 23, 24, 41, and in some cases the connection part 32 for the electronic processing unit 3.

[0070] The electronic processing unit 3 may be actually arranged inside the medical device 10. As a modification, as shown in FIG. 3, it is in the form of a unit that is separated from the plate 1 and away from the first and second handgrips 2 and 3, but is connected to these two elements by a wired or wireless communication device 37.

[0071] In one embodiment, the electronic processing unit 3 has a distributed architecture.

[0072] In particular, in this embodiment, the management of the medical device (including data processing and control of sensors and electrodes) is distributed among a plurality of microcontrollers each incorporating at least a computer and a recording medium. At least two local microcontrollers are arranged, for example, in each of the hand grips 2, 4 respectively. Thus, each local microcontroller is located near the electrodes 21, 22, and 41.

[0073] The central microcontroller has the task of adjusting the measurement sequence by adjusting the local microcontrollers and collecting the measurement values obtained by the local microcontrollers. As a variant, there may be only one local microcontroller communicating with the central microcontroller near the electrode. This set comprising one or more local microcontrollers, a central microcontroller, and their associated electronic memories forms a solution means equivalent to the computer 30 and the electronic memory 31 described above.

[0074] Each local microcontroller is preferably arranged as close as possible to the sensor on which it operates. Each local microcontroller incorporates a multiplexer 33, a power supply 34, and a voltmeter 36 respectively, enabling them to control the bioimpedance electrodes respectively. Thus, a local electronic processing unit similar to that described with reference to FIG. 3 is arranged as close as possible to the sensors of the device. Such a configuration makes it possible to improve the quality of the analog measurements by minimizing signal attenuation and noise.

[0075] Also, for control, it is advantageous for the local microcontroller to be arranged as close as possible to the photoplethysmography sensor 23, the emitting LED, and the receiving photodiode.

[0076] The central microprocessor also manages communication with the human-machine interface 5 assigned to the user of the medical device 10, particularly patients suffering from chronic kidney disease. The human-machine interface 5 forms part of the medical device 10.

[0077] The central microcontroller further manages communication with the network 20 in order to transmit data transmitted from the medical device 10 to the remote database 203.

[0078] In one embodiment, the central microcontroller manages communication via the network 20 with a remote computer 30, or any portable object, and there is a human-machine interface on these remote devices that enables a user of the monitoring system 100, particularly a medical expert, to examine data transmitted from the medical device and / or manage the settings within the medical device 10.

[0079] The present invention also relates to a computer-readable recording medium that includes instructions which, when executed by a computer, perform a method for calculating a water volume and cause the computer to perform calculations for estimating biological parameters such as blood pressure, vascular stiffness, heart rhythm, and oxygen saturation.

[0080] Accordingly, the electronic processing unit 3 can control the operation of the medical device 10 by instructing it to measure the bioimpedance between the patient's feet and hands. To do this, the power supply 34 generates a current via the electrodes 11, 12, 21, and 22, and then the induced electrical data can be measured, particularly using the voltage sensor 36. The voltage induced by the passage of the current is measured by the voltage sensor 36 at at least one measurement electrode, and by applying Ohm's law, the environment through which the current has passed, i.e., the bioelectrical impedance of the patient's body, can be determined.

[0081] To complement this, in one embodiment, the medical examination device 10 is capable of measuring the impedance in a region including the patient's heart region. To do this, a current is generated between the first and second hand electrodes 21, 22, 41, and then measurements are used to estimate the bioelectrical impedance of the environment through which the current has passed, i.e., the heart region. In this embodiment, the third electrode comprises several electrodes arranged in contact with the second needle.

[0082] In one mode of use, the power supply 34 injects a low-intensity current with an intensity in the range of 8 - 200 μA, or 8 - 150 μA, or 8 - 100 μA (e.g., about 32 μA) while allowing an error of 10%, and performs a selected frequency sweep ranging from 125 Hz to 500 kHz, or even from 125 Hz to 800 kHz. Preferably, the frequency sweep ranges from 4 kHz to 300 kHz. This frequency sweep enables passing through various types of cell membranes for each frequency zone and exploring the extracellular and intracellular zones. Alternatively, the intensity of the current injected by the power supply 34 may be in a wider range of values, for example, in the range of 8 - 200 μA.

[0083] Through that electrical measurement, the medical device 10 performs bioimpedance - or frequency-based impedance - spectroscopy, which provides a measurement of the volume of water in the body.

[0084] The medical device 10 comprises hardware elements 1, 2, 3, 4, 5, 11, 12, 13, 21, 22, 23, 24, 41, and / or software elements configured to perform all or some of the following processing operations: · Measuring the total mass of the user, · Measuring the impedance of the foot, · Measuring the volume Vi of intracellular water contained in the user's body, · Measuring the volume Ve of extracellular water contained in the user's body, · Measuring the total volume Vt of water contained in the user's body, · Measuring the dry weight, · Measuring the excess moisture content, · Optionally, measuring the change in dry weight, · Optionally, measuring the change in excess moisture, · Optionally, measuring the blood pressure, · Optionally, measuring the pulse wave, · Optionally, measuring the heart rate, · Optionally, measuring the blood oxygen saturation, · Optionally, measuring the electrocardiogram of the hand, · Optionally, measuring the skin temperature.

[0085] The total mass of the user, expressed in kilograms, can be determined by a measurement obtained from at least one load cell. To complement this, or alternatively, foot - hand impedance measurements can be used to determine the total weight of the user. Preferably, the total mass is measured with an accuracy of within at least 0.5 kilograms, or even within at least 0.1 kilograms, in the range of 0 to 150 kilograms, or even in the range of 0 to 200 kilograms.

[0086] The foot - hand impedance measurement can be performed by electrodes 11, 12, 21, and 22, which can inject a current between one of the user's feet and one of the user's hands and then measure the induced electrical data.

[0087] Analysis of the electrical data resulting from the foot - hand impedance measurement makes it possible to calculate the volume of water (in liters) contained in the user's body. This water volume can include the volume of all or part of the various fluid compartments of the human body.

[0088] In a preferred embodiment, from the electrical data resulting from the foot - hand impedance measurement, device 10 calculates, independently of each other, three water volumes contained in the user's body: · The volume of intracellular water Vi contained in the user's body, · The extracellular water volume Ve contained in the user's body, · The total water volume Vt contained in the user's body.

[0089] In another preferred embodiment, the intracellular water volume Vi, the extracellular water volume Ve, and the total water volume Vt are measured independently of each other.

[0090] In one embodiment, the total amount of water Vt contained in the patient's body is calculated using Equation 1.

[0091]

Number

[0092] The value of the equivalent resistivity ρ ∞ is obtained using Equation 2.

[0093]

Number

[0094] The value of the shape factor is obtained using Equation 3.

[0095]

Number

[0096] Analysis of the electrical data resulting from the foot-to-hand impedance measurement also makes it possible to calculate the user's dry weight, the volume of excess water in liters, and / or changes in dry weight and / or changes in excess water.

[0097] Analysis of the electrical data resulting from the foot-to-hand impedance measurement value and the measurement value supplied by the mass sensor 13 also makes it possible to calculate the amount of excess water in liters. Excess water corresponds to the excess amount of water present in the user's body, and this excess amount is generated by renal system dysfunction. Preferably, the accuracy of the excess water volume is within at least 0.1 liter.

[0098] Also, the analysis of the electrical data resulting from the foot - hand impedance measurement values and the measurement values supplied by the mass sensor 13 enables the calculation of the user's dry weight in kilograms, preferably with an accuracy of at least within 0.5 kilograms, and more preferably within 0.1 kilograms.

[0099] Advantageously, the device 10 enables the calculation of changes in fluid overload, particularly changes in fluid overload between two dialysis sessions.

[0100] In one embodiment, the foot - hand impedance measurement enables the determination of resistance (the real part of the impedance) and reactance (the imaginary part of the impedance). By determining the resistance and reactance associated with each impedance measurement, it becomes possible to utilize the impedance measurement using the BIVA (Bioimpedance Vector Analysis) method.

[0101] The analysis of the data resulting from the photoplethysmograph sensor 23 enables the calculation of the following: · Blood pressure in mmHg or cmHg, and / or · Blood oxygen saturation, percentage, accurate to one decimal place, and / or · The user's heart rate (beats per minute).

[0102] The hand - hand electrocardiogram measurement is performed using electrodes 21, 22, and 41 that enable the measurement of the cardiac electrical activity generated by the sinoatrial node of the heart, which acts as an autonomous power source, between the user's two hands. In particular, these measurements enable the obtaining of the user's electrocardiogram.

[0103] In one embodiment, the human - machine interface 5 enables the display of at least one data item selected from the following: · The total mass of the user, · The total volume Vt of the water contained in the user's body, · The user's dry weight, · Variations in the user's dry weight, · Excess moisture amount, · Variations in the excess moisture amount, · The user's heart rate, · The user's blood pressure, · The user's skin temperature, · Visual display of bioimpedance.

[0104] In one embodiment, the medical device further comprises means for communication, particularly wireless communication, with a portable device, and the portable device comprises communication means and storage means containing body measurement information regarding the user, including at least one of the information items of date of birth, ethnicity, height, and gender.

[0105] For this purpose, in one embodiment, the medical device can communicate with an application installed on the user's mobile phone. The storage means may be the phone's memory, and the application installed on the phone collects body measurement data from the phone memory and communicates them to the medical device.

[0106] Alternatively, the storage means may be an electronic card belonging to the user, and the data recorded on the electronic card can be retrieved by the medical device directly (if the medical device can read the card) or indirectly via an application installed on the user's phone.

Claims

1. A medical device (10) that monitors the user's biological parameters, - The user's mass measuring plate (1), - First and second electrodes (11, 12, 21, 22) perform impedance measurements at at least two separate frequencies, particularly low or medium frequency and high frequency, and measure at least the amount of water in the user's body. - A device for measuring blood pressure and / or heart rate (23) A medical device equipped with the following features.

2. The medical device according to claim 1, wherein the device for measuring blood pressure and / or heart rate is a photoplethysmographic sensor (23) that can also measure the oxygen saturation of the user's blood.

3. The plate (1) is equipped with the first electrodes (11, 12) which can measure the impedance of one of the user's feet, The second electrodes (21, 22) are arranged to measure the impedance in the user's first hand, The impedance measurement includes at least one impedance measurement between one of the user's feet and one of the user's hands, in particular an impedance measurement between a foot and a hand located on the same half of the user's body, preferably the right half. The medical device according to claim 1.

4. The medical device (10) includes a third electrode (41) positioned in contact with the user's finger, The medical device according to claim 3, wherein the second and third electrodes (21, 41) together can record an electrocardiogram between the user's first hand and second hand.

5. The medical device according to claim 1, further comprising a temperature sensor (24) that enables measurement of the user's skin temperature.

6. The medical device according to claim 1, further comprising means for adjusting the height of the second electrodes (21, 22) relative to the plate (1) to adjust the vertical distance measured between the second electrodes and the plate to match the user's height.

7. The medical device (10) comprises a first handgrip (2), on which the second electrodes (21, 22) are arranged on a rigid arm substantially parallel to the plate (1). The medical device according to claim 6, wherein the adjustment means is a system that adjusts the height of the rigid arm equipped with the first rigid handgrip (2) relative to the plate (1), thereby enabling the height of the first rigid handgrip (2) to be adjusted relative to the plate (1).

8. The medical device according to claim 1, wherein the electrodes (11, 12, 21, 22, 41) of the medical device (10) are adapted to measure impedance in the user's foot or hand over a frequency sweep ranging from 125 Hz to 500 kHz, or even from 125 Hz to 800 kHz, or even from 4 kHz to 300 kHz, by injecting a current having an intensity of 8 to 200 μA, or 8 to 150 μA, or 8 to 100 μA, or about 32 μA, with a 10% increase or decrease.

9. The medical device according to claim 1, wherein the impedance measurement includes at least one first measurement at a low frequency of 125 Hz to 5 kHz or a medium frequency of 5 kHz to 50 kHz, at least one second measurement at a high frequency of 50 kHz to 300 kHz, or 500 kHz, or 800 kHz, and optionally at least one third measurement at a third frequency different from the aforementioned two frequencies.

10. The medical device comprises an electronic processing unit (3), The medical device according to claim 1, wherein electrodes (11, 12, 21, 22, 41), and / or a device (23) for measuring blood pressure and / or heart rate, and / or a temperature sensor (24) are connected to the electronic processing unit (3) by a wired or wireless communication device (37) so that impedance measurements obtained using the electrodes can be transmitted to the electronic processing unit (3), and the electronic processing unit (3) can control the current transmitted by the electrodes to the user's hand or foot.

11. The system comprises hardware elements (1, 2, 3, 4, 5, 11, 12, 13, 21, 22, 23, 24, 41) and / or software elements configured to obtain water volume measurements from the foot-hand impedance measurements, wherein the water volume is - Measurement of the volume of intracellular water (Vi) contained in the user's body. - Measurement of the volume of extracellular water (Ve) contained in the user's body. - Measurement of the total volume of water (Vt) contained in the user's body. Including at least one of the following: The medical device according to claim 1.

12. ・Measure the dry weight, • Measure the amount of excess fluid. ・Optionally, measure the change in dry weight. ・Optionally, measure changes in excess water content. ・As an option, blood pressure measurement, ・Optionally, pulse wave measurement is available. ・Optionally, measure heart rate. ・Optionally, measure blood oxygen saturation. ・Optionally, measure a hand-to-hand electrocardiogram. ・Optionally, measure skin temperature. The system comprises hardware elements (1, 2, 3, 4, 5, 11, 12, 13, 21, 22, 23, 24, 41) and / or software elements configured to perform the following: The medical device according to claim 1.

13. The medical device according to claim 11, wherein the measurement of the volume of intracellular water (Vi), the volume of extracellular water (Ve), and the total volume of water (Vt) are performed independently of each other.

14. - Total mass of users, - The total volume of water contained in the user's body (Vt), - User's dry weight, - Fluctuations in the user's dry weight, • Excessive fluid intake, Fluctuations in excess fluid levels, - User's heart rate, - User's blood pressure, - User's skin temperature, ・Visual display of bioelectrical impedance, It includes a human-machine interface (5) that enables the display of at least one data item selected from among the following, The medical device according to claim 11.

15. The medical device according to claim 1, comprising means for wireless communication with a portable device such as an electronic card or telephone, which has physical measurement information relating to a user, including at least one of the information items of date of birth, ethnicity, height, and sex.

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