Medical device for monitoring biological parameters

Abstract

Medical device for monitoring biological parameters. Medical device (10) for monitoring a user's biological parameters comprising: - a platform (1) for measuring the user's mass, - at least one first and one second electrode (11, 12, 21, 22) for measuring impedance, and - a blood pressure and / or heart rate measurement device (23). Figure for the abstract: 2

Description

Title of the invention: Medical device for monitoring biological parameters.

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

[0002] Daily monitoring of water and salt (sodium chloride, potassium, calcium, phosphorus) intake is essential in patients with chronic renal failure. Indeed, poor management of these intakes impairs the patient's tolerance to dialysis (particularly through the occurrence of intradialytic hypotension and / or cramps) and significantly increases the likelihood of developing disease-related side effects, such as hypertension and / or cardiovascular disorders.

[0003] Only a high degree of deprivation, particularly of water and salts, allows patients with chronic kidney disease to live with their condition. It is therefore essential to provide them with means of daily control over their fluid intake from food, thereby improving their tolerance to dialysis and reducing the risk of dialysis side effects.

[0004] In current practice, daily monitoring of fluid intake is carried out empirically and approximately by simple weighing and comparison of the measured weight to a reference weight known as the patient's "ideal weight." The patient's reference weight is also called "dry weight," as it corresponds to an estimate of the weight the patient should normally reach at the end of a dialysis session when all excess water has been removed. The dialysis patient's dry weight is generally determined empirically by the healthcare team as the lowest weight that can be tolerated by the patient and that does not generate adverse effects. It is a compromise, reviewed in consultation, between clinical observation of more or less observable symptoms, the history of dialysis intolerances, and measurements of weight and blood pressure.Thus, in most cases, dry weight is estimated by trial and error, with errors in dry weight estimation being detectable either through the development of adverse effects during dialysis sessions (in case of underestimation of dry weight) or through the appearance of symptoms of water retention (in case of overestimation of dry weight).

[0005] A body composition assessment would advantageously make it possible to distinguish water mass from total mass and thus to determine a more reliable dry weight to which to refer in order to manage the amount of fluid a patient absorbs between two dialysis sessions, and thus determine the volume of water to be removed during a dialysis session.

[0006] In addition, daily home monitoring of indicators relating to side effects of the disease would improve responsiveness in the management of these side effects, particularly the management of hypertension and cardiovascular disorders.

[0007] Devices currently exist for performing body composition assessments, particularly at home. However, these devices are generally poorly suited to the body composition and mobility of a patient with chronic kidney disease, especially since the median age of a dialysis patient is 71 years and the disease is almost always associated with multiple comorbidities. Furthermore, existing devices do not address the specific needs of these patients, such as the detection and monitoring of the disease's side effects.

[0008] Furthermore, the various devices measuring the body composition of dialysis patients provide significantly different results depending on the device used. For this reason, it is not possible to compare measurements from different devices for the same patient. Consequently, it is not possible to monitor a patient using data from different devices.

[0009] The object of the invention is to provide a biological parameter monitoring device that remedies the above drawbacks and improves upon known prior art devices.

[0010] In particular, the invention aims to provide a device that is simple and reliable and that allows daily monitoring of the patient's weight and / or the amount of fluid absorbed between two dialysis sessions and / or daily monitoring of the side effects of chronic renal failure.

[0011] To this end, the invention relates to a medical device for monitoring a user's biological parameters comprising - a platform for measuring the user's mass, - at least one first and one second electrode for performing impedance measurements, and - a device for measuring blood pressure and / or heart rate.

[0012] In one embodiment, the blood pressure and / or heart rate measurement device is a photoplethysmographic sensor which also allows for a measurement of the oxygen saturation of the user's blood.

[0013] In one embodiment, the platform is equipped with the first electrode allowing impedance measurements to be taken at the level of one foot of the user, and the second electrode is arranged so as to allow impedance measurements to be taken at the level of one hand of the user.

[0014] In one embodiment, the medical device comprises a third electrode disposed in contact with a second hand of the user, the second and third electrodes are suitable together for recording an electrocardiogram between the first and second hands of the user.

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

[0016] In one embodiment, the medical device includes a means for adjusting the height of the second electrode relative to the platform, so as to adapt a vertical distance, measured between the second electrode and the platform, to a user's height.

[0017] In one embodiment, the medical device includes a first handle, on which the second electrode is fixed, arranged on a rigid arm substantially parallel to the platform, and the adjustment means is a system for adjusting the height of said rigid arm including the first handle relative to the platform, to allow adjustment of the height of the first handle relative to the platform.

[0018] In one embodiment, electrodes of the medical device are suitable for impedance measurement at the level of a foot or hand of a user by injecting a current of intensity between 8 and 200 pA, or between 8 and 150 pA or between 8 and 100 pA or even around 32 pA plus or minus 10%, and according to a frequency sweep extending from 125 Hz to 500 kHz, or even extending between 4 kHz and 300 kHz.

[0019] In one embodiment, the medical device includes an electronic processing unit. The electrodes and / or the blood pressure and / or heart rate measuring device and / or the temperature sensor are connected to the electronic processing unit by a wired or wireless communication device, such that the impedance measurements taken via the electrodes are able to be transmitted to the electronic processing unit and such that the electronic processing unit is able to control the current transmitted by the electrodes at the level of a hand or foot of a user.

[0020] In one embodiment, the medical device comprises hardware and / or software components configured to implement the following treatments: - measurement of a user's total mass, - measurement of foot-hand impedance, - Measurement of the volume of intracellular water contained in a user's body, - Measurement of the volume of extracellular water contained in a user's body, - Measurement of the total volume of water contained in a user's body, - Measurement of dry weight, - measurement of a volume of hyperhydration, - and optionally, measurement of a change in dry weight, - and optionally measurement of hyperhydration variation, - and optionally measurement of blood pressure, - and optionally measurement of a pulse wave, - and optionally measurement of a heart rate, - and optionally measurement of a blood oxygen saturation level, - and optionally measurement of a hand-to-hand electrocardiogram, - and optionally measurement of a skin temperature.

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

[0022] In one embodiment, the medical device includes a human-machine interface allowing the display of at least one piece of data selected from: - a total user mass, - the total volume of water contained in a user's body, - a user's dry weight, - a variation in a user's dry weight, - a volume of hyperhydration, - a variation of hyperhydration, - a user's heart rate, - a user's blood pressure, - a user's skin temperature, - a bioimpedance visualization.

[0023] The attached drawings represent, by way of example, an embodiment of a monitoring device according to the invention.

[0024] Fig. 1 represents a monitoring system equipped with a medical monitoring device according to the invention.

[0025] Figure [Fig.2] represents an embodiment of a medical monitoring device according to the invention.

[0026] Fig. 3 schematically represents an electronic processing unit of the medical monitoring device according to the embodiment of the invention.

[0027] An example of a biological parameter monitoring system equipped with a monitoring device according to the invention is described below with reference to Figures 1 to 3.

[0028] In the remainder of this document, the term "weight" should be understood as a mass measured in kilograms.

[0029] The 100 medical monitoring system mainly comprises the following elements: - at least one medical monitoring device 10, - a distributed network infrastructure 20, and - at least one 30 terminal for healthcare professionals.

[0030] The distributed network infrastructure 20 comprises a network 201, a centralized memory 202 hosting a database 203, and programs for processing the data contained in the database. The centralized memory also hosts programs for managing communication between a control unit 3 of each of the at least one medical monitoring device 10 and the user terminals 30 dedicated to healthcare professionals.

[0031] Such an embodiment, implementing a distributed architecture, makes it possible to perform the simplest calculations directly in the medical device 10, and then to delegate more complex calculations to a computer server connected to the database 203.

[0032] In a minimal embodiment, the medical monitoring system 100 could consist solely of a medical device 10. The calculations would then be entirely performed locally, i.e. in the medical device 10.

[0033] In the remainder of the document, the medical monitoring device 10 is also referred to as "medical device 10" or "device 10".

[0034] The medical device 10, particularly represented by [Fig. 2], comprises: - a platform 1 for measuring the user's mass, - at least one first and one second electrode 11, 12, 21, 22 for measuring impedance, and - a blood pressure and / or heart rate measuring device 23.

[0035] In one embodiment, the platform 1 is equipped with at least one load cell 13 for measuring the total mass of the user. Advantageously, the platform is equipped with several load cells 13, for example four load cells 13, in order to optimize the accuracy of the measurement of the user's total mass.

[0036] In one embodiment, the platform 1 is equipped with the first electrode 11, 12 for performing impedance measurements at the level of a user's foot. Furthermore, the second electrode 21, 22 is arranged to allow for performing impedance measurements at the level of the user's first hand.

[0037] The first and second electrodes are thus able to perform impedance measurements between a user's foot and hand, in particular impedance measurements between a user's homolateral foot and hand. In the remainder of this document, impedance measurements between a user's foot and hand are referred to as "foot-hand impedance measurements".

[0038] As a remark, impedance measurement means any direct and indirect measurement allowing such a quantity to be obtained directly, such as measurements of voltage, voltage variations as a function of time, current and / or current variations as a function of time, or their derivative.

[0039] More generally, in the remainder of this document, the term "measure" may refer to Data obtained directly from sensors, and / or data calculated from data collected at the sensor level. The calculations may include algorithmic calculations, in particular calculations involving learning algorithms, for example neural network learning calculations.

[0040] Furthermore, the term "foot" is used to designate a body part that may include a foot, in particular the sole, the top of the foot and the toes, and may extend above the ankle. Similarly, the term "hand" is used to designate a body part that may include a hand, in particular the palm, the back of the hand and the fingers, and may extend above the wrist.

[0041] Advantageously, the platform 1 may include more than one electrode, for example, two electrodes 11, 12 arranged so as to be simultaneously in contact with the foot of a user standing on the platform. For example, one electrode 11 may be in contact with the heel of the foot while another electrode 12 is in contact with the forefoot. In the remainder of this document, the term "first electrode" refers to one or more electrodes arranged on the platform 1. The first electrode is intended to perform impedance measurements between the user's foot and another area of ​​the user's body.

[0042] In addition or alternatively, at least two electrodes 21, 22 may be positioned on the user's first hand. For example, one electrode 21 may be in contact with the palm of the first hand and another electrode 22 may be in contact with a finger of the first hand. In the remainder of this document, the term "second electrode" refers to one or more electrodes positioned in contact with a user's first hand and intended to perform measurements on the user's first hand.

[0043] Thus, depending on the number of electrodes included in the medical device 10, the first and second electrodes can allow different types of impedance measurements to be carried out between a foot and the first hand of the user, for example bipolar, tripolar or quadripolar measurements.

[0044] The medical device 10 further includes a blood pressure and / or heart rate measuring device 23.

[0045] In one embodiment, the blood pressure and / or heart rate measurement device is a photoplethysmographic sensor 23.

[0046] The photoplethysmographic sensor 23 allows for all or part of the following measurements: blood pressure, heart rate and oxygen saturation of the user's blood.

[0047] The photoplethysmographic sensor 23 may include an array of at least two emitting LEDs and one or two receiving photodiodes. The at least two emitting LEDs produce light of two different wavelengths, the wavelengths the respective wavelengths of these LEDs can be, for example, between 500 and 750 nm for the first and between 850 and 1000 nm for the second.

[0048] Other embodiments of a blood pressure measuring device 23 are conceivable, for example a blood pressure cuff.

[0049] The medical device may further include a third electrode 41 disposed in contact with the user's second hand. In the remainder of this document, the term "third electrode" refers to one or more electrodes disposed in contact with a user's second hand and intended to perform measurements on the user's second hand.

[0050] Advantageously, the second and third electrodes 21, 22, 41 are then together suitable for recording an electrocardiogram between the first and second hands of the user.

[0051] In the remainder of this document, impedance measurements between the first and second hands of a user are referred to as "hand-to-hand impedance measurements".

[0052] Furthermore, the second and third electrodes 21, 22, 41 are then suitable together - for a measurement of a heart rate, and / or - to a measurement of a pulse wave circulating between the second and third electrodes 21, 22, 41, and / or - to a measurement of the speed of the pulse wave circulating between the second and third electrodes 21, 22, 41.

[0053] The medical device may further include a temperature sensor 24 enabling a measurement of a user's temperature.

[0054] Advantageously, the medical device includes a means for adjusting the height of the second electrode 21, 22 relative to the platform 1, so as to adapt a vertical distance, measured between the second electrode and the platform, to the user's height. Thus, the second electrode 21, 22 can be positioned to accommodate a natural hand position when it comes into contact with the second electrode 21, 22.

[0055] The adjustment means can take various forms. For example, in a preferred embodiment, the device 10 can include a first handle 2 on which the second electrode 21, 22 is fixed. The adjustment means can then be a system for adjusting the height of the first handle 2 relative to the platform 1.

[0056] The medical device 10 may further include a second handle 4 equipped with the third electrode 4L. The adjustment means may also allow the height of the second handle to be adjusted relative to the platform 1.

[0057] According to the embodiment, the medical device therefore comprises a platform for receiving the user's feet, and two handles for receiving the user's hands, or even arms. Advantageously, these handles are rigid, and are arranged on two rigid arms, as will be detailed later.

[0058] The blood pressure and / or heart rate measuring device 23 and / or the temperature sensor 24 can be positioned on the first or second handle 2, 4.

[0059] The medical device 10 further comprises an electronic processing unit 3, particularly represented by [Fig. 3]. This unit integrates at least one computer 30 and a connector 32 enabling a connection from the computer 30 to sensors 13, 23, 24 and electrodes 11, 12, 21, 22, 41 of the medical device 10. The computer 30 can thus receive the data measured by the sensors. The electronic processing unit 3 further comprises a data storage medium or electronic memory 31. It also includes a power source 34, connected to all or part of the electrodes, thus enabling the injection of an electrical current via the electrodes. It further comprises at least one voltage sensor 36 for collecting physiological data via the measuring electrodes. This voltage sensor 36 can alternatively be located at a measuring electrode, or remotely, within the electronic processing unit 3, as shown.Finally, the electronic processing unit 3 includes a communication device 35, which allows it to transmit electronic data externally, such as body composition measurements or blood pressure, and / or to receive data externally, such as parameter data or messages from a healthcare professional. The electronic memory 31 also allows for the storage of measurements and / or data calculated locally in the medical device 10. These measurements and / or data are then transmitted via the network 20 to the database 203. Advantageously, the measurements and / or data calculated locally in the medical device 10 are backed up for a minimum period in the memory 31, particularly in the event of network 20 unavailability. The minimum backup period could be, for example, 15 days.

[0060] The data in the electronic memory 31 are readable by the calculator 30, or even by any other computer in the electronic processing unit 3, on which is recorded a computer program for the operation of the medical device 10, in particular for the implementation of the measurements and calculations of biological parameters described later in this document.

[0061] In an embodiment shown in [Fig. 2], the medical device 10 comprises a support 6 connected to the platform 1 and to the first and second handles 2, 4. The support 6 comprises a vertical leg 60 fixed at its lower part to the platform 1. The vertical leg 60 is preferably perpendicular to the platform 1. It is positioned so as to allow a user to climb onto the platform 1 and place one of their feet if- simultaneously on the two electrodes of the plateau 11, 12.

[0062] The support 6 also includes a U-shaped frame composed of three parallelepiped portions 61, 62, 63 fixed together, a central portion 63 interposed between two portions 61, 62 forming respectively the two arms of the U. In one embodiment, the portions 61, 62, 63 are rigidly fixed together and the assembly they form extends in a substantially horizontal plane, i.e. parallel to the plane of the platform 1. Alternatively, a rotational movement of the portions forming the arms 61, 62 is possible around the central portion 63. The arm 61 includes a first end connected to the central portion 63 and a second end connected to the first handle 2. The arm 62 includes a first end connected to the central portion 63 and a second end connected to the second handle 4. The central portion 63 is fixed perpendicularly to the vertical leg 60, in an upper area of ​​the vertical foot 60.In an advantageous embodiment, the fixing between the vertical foot 60 and the central portion 63 includes a means for adjusting the height of the U-shaped frame. The height adjustment of the U-shaped frame advantageously allows the height of the handles 2, 4 to be adjusted, i.e. the vertical distance separating the handles 2, 4 from the platform 1.

[0063] According to one embodiment, the two branches 61, 62 of the medical device 10 are presented as two rigid arms.

[0064] The two branches 61, 62 comprise the electrode(s) intended to cooperate with the hand of a user, via or without a handle 2.

[0065] Alternatively, the rigid frame positioned at hand height, to cooperate with a user's hands, may have a shape other than a U.

[0066] Furthermore, the height adjustment means may include a locking / unlocking device, allowing the two arms 61, 62 to be fixed or unfixed relative to the support 6, and thus to be held at a chosen height. This locking / unlocking device also allows this position to be unlocked, to permit their movement and height adjustment. For this purpose, a guiding device may allow their movement, for example by at least one guide rail, in particular a vertical translational movement. The support 6 may, for example, slide vertically for adjustment, and then be held at a chosen height by a mechanism of pins inserted into a certain respective opening in the support and the vertical leg corresponding to a chosen height for the support.

[0067] Thus, the device ensures that the electrodes are set at the correct height to cooperate with the hand or hands of a user, and then ensures that this height will be maintained constant during regular measurements, for example daily, for optimal consistency between the different measurements.

[0068] The vertical foot and / or the U-shaped frame are preferably hollow so that to be able to integrate the connector 32 of the sensors 11, 12, 13, 21, 22, 23, 24, 41 and possibly the electronic processing unit 3.

[0069] The electronic processing unit 3 can be arranged within the medical device 10 itself. Alternatively, it is presented as a unit distant from the tray 1 and the first and second handles 2, 3 but connected to these two elements by a communication device 37, wired or wireless, as represented by [Fig.3].

[0070] In one embodiment, the electronic processing unit 3 has a distributed architecture.

[0071] In particular, in this embodiment, the management of the medical device (including data processing and control of the sensors and electrodes) is distributed among several microcontrollers, each integrating at least one computer and a storage medium. For example, at least two local microcontrollers are positioned at each handle 2, 4. Each local microcontroller is thus located near the electrodes 21, 22, and 41.

[0072] A central microcontroller orchestrates the measurement process by coordinating the local microcontrollers and collecting the measurements performed by the local microcontrollers. Alternatively, there may be a single local microcontroller located near the electrodes, communicating with a central microcontroller. This combination of local (or local) and central microcontrollers and their associated electronic memories forms a solution equivalent to the computer 30 and the electronic memory 31 described previously.

[0073] Each local microcontroller is advantageously placed as close as possible to the sensors it controls. Each local microcontroller integrates a multiplexer 33, a power supply 34, and a tensiometer 36, enabling each to manage the bioimpedance electrodes. Thus, a local electronic processing unit, similar to that described with reference to [Fig. 3], is positioned as close as possible to the device's sensors. This arrangement improves the quality of the analog measurements by minimizing signal attenuation and noise.

[0074] A local microcontroller is further advantageously placed as close as possible to the photoplethysmographic sensor 23, the emitting LEDs and the receiving photodiodes for their control.

[0075] The central microcontroller also manages communication with a human-machine interface 5 dedicated to a user of the medical device 10, in particular a patient suffering from chronic renal failure. The human-machine interface 5 is part of the medical device 10.

[0076] The central microcontroller also manages communication with the network 20, for the transmission of data from the medical device 10 to the remote database 203.

[0077] In one embodiment, the central microcontroller manages communication via the network 20 with a remote computer 30, or any portable object, on which may be a human-machine interface to allow a user of the monitoring system 100, in particular a healthcare professional, to consult the data from the medical device and / or to configure the medical device 10.

[0078] The invention also relates to a computer-readable recording medium comprising instructions which, when executed by a computer, lead the computer to implement the method of calculating a water volume, as well as calculations for estimating biological parameters, such as blood pressure, vascular stiffness, heart rate and oxygen saturation.

[0079] The electronic processing unit 3 can thus control the operation of the medical device 10 by taking bioimpedance measurements between a patient's foot and hand. To do this, the electrical source 34 can generate an electric current via the electrodes 11, 12, 21 and 22, and then measure induced electrical data, notably via the voltage sensor 36. The voltage induced by the current is measured at at least one measuring electrode by the voltage sensor 36, and applying Ohm's law makes it possible to determine the bioelectrical impedance of the medium through which the current flows, i.e., the patient's body.

[0080] In addition, in one embodiment, the examination medical device 10 could be suitable for impedance measurement in an area including the patient's cardiac region. For this purpose, a current is generated between electrodes of the first and second hands 21, 22, 41, and measurements are taken to determine the bioelectrical impedance of the medium traversed, i.e., the cardiac region. In this embodiment, the third electrode would advantageously comprise several electrodes arranged in contact with the second hand.

[0081] In one operating mode, the electrical source 34 injects a low-intensity current in the range of 8 to 200 pA, or 8 to 150 pA, or 8 to 100 pA—for example, around 32 pA plus or minus 10%—according to a chosen frequency sweep, which can extend from 125 Hz to 500 kHz. Preferably, the frequency sweep extends from 4 kHz to 300 kHz. This frequency sweep allows the different types of cell membranes to be traversed by frequency range and the extra- and intracellular areas to be explored. Alternatively, the intensity of the current injected by the electrical source 34 could be in a wider range, for example, in the range of 8 to 200 pA.

[0082] Through its electrical measurements, the medical device 10 implements a bioimpedance spectroscopy - or frequency impedance - which provides a measurement of the water volume in the body.

[0083] The medical device 10 comprises material elements 1, 2, 3, 4, 5, 11, 12, 13, 21, 22, 23, 24, 41 and / or software configured to implement all or part of the following processes: - measurement of a user's total mass, - measurement of foot-hand impedance, - Measurement of intracellular water volume V contained in a user's body, - Measurement of extracellular water volume Ve contained in a user's body, - Measurement of total water volume Vt contained in a user's body, - Measurement of dry weight, - Measurement of hyperhydration volume - and optionally, measurement of a change in dry weight, - and optionally, measurement of a variation in hyperhydration, - and optionally, blood pressure measurement, - and optionally measurement of a pulse wave, - and optionally measurement of a heart rate, - and optionally measurement of a blood oxygen saturation level, - and optionally measurement of a hand-to-hand electrocardiogram, - and optionally measurement of a skin temperature.

[0084] The user's total mass, expressed in kilograms, can be determined by measurements from at least one load cell. In addition, or alternatively, foot-hand impedance measurement can be used to determine the user's total weight. Preferably, the total mass measurement is performed over a range of 0 to 150 kilograms, or even over a range of 0 to 200 kilograms, with an accuracy of at least 0.5 kilograms, or even at least 0.1 kilograms.

[0085] Foot-hand impedance measurements are carried out via electrodes 11, 12, 21 and 22, which allow an electric current to be injected between a foot and a hand of the user, and then induced electrical data to be measured.

[0086] Analysis of electrical data from foot-hand impedance measurements allows for the calculation of the body water volume in liters contained in the user. The body water volume may include the volume of all or part of the various fluid compartments of the human body.

[0087] In a preferred embodiment, from electrical data obtained from foot-hand impedance measurements, the device 10 calculates, independently of each other, three volumes of water contained in the body of a user: - a volume of intracellular water V; contained in the body of a user, - a volume of extracellular water Ve contained in the body of a user, - a total volume of water Vt contained in the body of a user.

[0088] In a preferred embodiment, the measurement of an intracellular water volume Vi, the measurement of an extracellular water volume Ve and the measurement of a total water volume Vt are carried out independently of each other.

[0089] In one embodiment, the total volume of water Vt contained in the body of a patient is calculated according to the Mathl formula.

[0090] [Math.l]

[0091] where - Kh is the patient's fitness coefficient. - p°° is the equivalent resistivity of the two extracellular and intracellular compartments, - H is the patient's height in cm. - W is the weight in kg. - dB is the density of the patient's body. - is the resistance extrapolated to infinite frequency by the Cole-Cole model.

[0092] The value of the equivalent resistivity P™ is obtained according to the formula Math2.

[0093] [Math.2]

[0094] where - MNG is the fat-free mass in kilograms.

[0095] The value of the shape coefficient is obtained according to the formula Math3

[0096] [Math.s3]

[0097] where - ^arm -, ^trunk -, ^leg are respectively the length in centimeters of an arm, a trunk and a leg of the patient, - ^arms -, Cu- <mc et Cjamjx sont respectivement une circonférence en centimètres d’un bras, d’un tronc et d’une jambe du patient.

[0098] The analysis of electrical data from foot-hand impedance measurements also makes it possible to calculate the user's dry weight, a volume of hyperhydration in liters and / or a variation in dry weight, and / or a variation in hyperhydration.

[0099] Analysis of electrical data from foot-hand impedance measurements and measurements provided by mass sensors 13 also allows for the calculation of an overhydration volume in liters. Overhydration corresponds to an excess of water present in the user's body, this excess being generated by renal dysfunction. Preferably, the accuracy of the overhydration volume is at least 0.1 liters.

[0100] The analysis of electrical data from foot-hand impedance measurements and measurements provided by mass sensors 13 also allows the calculation of a dry weight of the user in kilograms, preferably with an accuracy of at least 0.5 kilogram, or even at least 0.1 kilogram.

[0101] Advantageously, the device 10 allows the calculation of a hyperhydration variation, in particular a hyperhydration variation between two dialysis sessions.

[0102] In one embodiment, foot-hand impedance measurements allow the determination of a resistance (real part of the impedance) and a reactance (imaginary part of the impedance). Determining the resistance and reactance relative to each impedance measurement allows the impedance measurements to be analyzed using a method known as BIVA (for "Bioimpedance Vector Analysis").

[0103] Analysis of the data from the photoplethysmographic sensor 23 allows calculation - blood pressure in mmHg or cmHg, and / or - blood oxygen saturation as a percentage with decimal precision, and / or - the user's heart rate in beats per minute.

[0104] Hand-to-hand electrocardiogram measurements are taken via electrodes 21, 22, and 41, which measure the cardiac electrical activity between the user's two hands, emitted by the sinoatrial node of the heart, which acts as an autonomous electrical source. In particular, these measurements allow for obtaining an electrocardiogram of the user.

[0105] In one embodiment, the human-machine interface 5 allows the display of at least one piece of data chosen from: - a total user mass, - a total volume of water Vt contained in the body of a user, - a user's dry weight, - a variation in a user's dry weight, - a volume of hyperhydration,

[0106] - a variation of hyperhydration

[0107] - a user's heart rate, - a user's blood pressure, - a user's skin temperature, - a bioimpedance visualization.

Claims

Demands

1. A medical device (10) for monitoring a user's biological parameters, comprising: - a platform (1) for measuring the user's mass, - at least one first and one second electrode (11, 12, 21, 22) for performing impedance measurements, and - a blood pressure and / or heart rate measurement device (23), characterized in that electrodes (11, 12, 21, 22, 41) of the medical device (10) are capable of impedance measurement at the level of a user's foot or hand by injecting a current with an intensity between 8 and 200 pA, or between 8 and 150 pA, or between 8 and 100 pA, or even around 32 pA plus or minus 10%, and according to a frequency sweep ranging from 125 Hz to 500 kHz, or even extending between 4kHz and 300kHz.

2. Medical device (10) according to the preceding claim, characterized in that the blood pressure and / or heart rate measurement device is a photoplethysmographic sensor (23) which also allows for measurement of the oxygen saturation of the user's blood.

3. Medical device (10) according to any one of the preceding claims, characterized in that the platform (1) is equipped with the first electrode (11, 12) enabling impedance measurements to be taken at the level of one foot of the user, and in that the second electrode (21, 22) is arranged so as to enable impedance measurements to be taken at the level of one hand of the user.

4. Medical device (10) according to the preceding claim, characterized in that it comprises a third electrode (41) disposed in contact with a second hand of the user, and in that the second and third electrodes (21, 41) are together capable of recording an electrocardiogram between the first and second hands of the user.

5. Medical device (10) according to any one of the preceding claims, characterized in that it comprises a temperature sensor (24) enabling a measurement of the user's skin temperature.

6. Medical device (10) according to any one of the preceding claims, characterized in that it includes a means for adjusting the height of the second electrode (21, 22) relative to the platform (1), so as to adapt a vertical distance, measured between the second electrode and the platform, to a user's height.

7. Medical device (10) according to the preceding claim, characterized in that it comprises a first handle (2), on which is fixed the second electrode (21, 22), arranged on a rigid arm substantially parallel to the platform (1), and in that the adjustment means is a system for adjusting the height of said rigid arm comprising the first handle (2) relative to the platform (1), to allow adjustment of the height of the first handle (2) relative to the platform (1).

8. Medical device (10) according to any one of the preceding claims, characterized in that it comprises an electronic processing unit (3), in that the electrodes (11, 12, 21, 22, 41) and / or the blood pressure and / or heart rate measuring device (23) and / or the temperature sensor (24) are connected to the electronic processing unit (3) by means of a wired or wireless communication device (37), such that the impedance measurements taken via the electrodes are capable of being transmitted to the electronic processing unit (3) and such that the electronic processing unit (3) is capable of driving the current transmitted by the electrodes to a hand or foot of a user.

9. Medical device (10) according to any one of the preceding claims, characterized in that it comprises hardware (1, 2, 3, 4, 5, 11, 12, 13, 21, 22, 23, 24, 41) and / or software configured to perform the following operations: - measurement of a user's total mass, - measurement of foot-hand impedance, - measurement of intracellular water volume (Vi) in a user's body, - measurement of extracellular water volume (Ve) in a user's body, - measurement of total water volume (Vt) in a user's body, - measurement of dry weight, - measurement of hyperhydration volume, - and optionally measurement of dry weight variation, - and optionally measurement of hyperhydration variation, - and optionally measurement of blood pressure, - and optionally measurement of pulse wave, - and optionally measurement of heart rate, - and optionally measurement of blood oxygen saturation level, - and optionally measurement of a hand-to-hand electrocardiogram, - and optionally measurement of a skin temperature.

10. Medical device (10) according to the preceding claim, characterized in that the measurement of an intracellular water volume (V;), the measurement of an extracellular water volume (Ve) and the measurement of a total water volume (Vt) are carried out independently of each other.

11. Medical device (10) according to the preceding claim, characterized in that it comprises a human-machine interface (5) allowing a display of at least one data selected from: - a total mass of a user, - a total water volume (Vt) contained in the body of a user, - a dry weight of a user, - a variation in dry weight of a user, - a volume of hyperhydration, - a variation in hyperhydration, - a heart rate of a user, - a blood pressure of a user, - a skin temperature of a user, - a bioimpedance visualization.

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