BIOIMPEDANCE MEASUREMENT DEVICE

Abstract

A bioimpedance-measuring device comprising a band configured so as to surround a wrist of a first arm of a user and on which there are arranged at least two current-injecting electrodes and at least two potential-measuring electrodes, said measuring device furthermore comprising a system for collecting raw bioimpedance data from the potential-measuring electrodes and a system for processing raw data in order to obtain at least one monitoring measurement and information signifying a pulmonary bioimpedance condition, said collection system being carried by the band and configured so as to communicate with the processing system.

Claims

1-13. (canceled)

14. A bioimpedance-measuring device, comprising: a band configured so as to surround a wrist of a first arm of a user and on which there are arranged at least two current-injecting electrodes and at least two potential-measuring electrodes; a collection system for collecting raw bioimpedance data from the at least two potential-measuring electrodes; and a raw data processing system for obtaining, based at least on the collected raw bioimpedance data, at least one monitoring measurement and information signifying a pulmonary bioimpedance condition, wherein a first current-injecting electrode of the at least two current-injecting electrodes and a first potential-measuring electrode of the at least two potential-measuring electrodes are arranged on an inner surface of the band so as to be in contact with the wrist of the first arm of the user, a second current-injecting electrode of the at least two current-injecting electrodes and a second potential-measuring electrode of the at least two potential-measuring electrodes are arranged on an outer surface of the band and configured so as to have an interface surface with a part of a second arm of the user, and the collection system is carried by the band and configured so as to communicate with the raw data processing system.

15. The bioimpedance-measuring device according to claim 14, wherein the first current-injecting electrode of the at least two current-injecting electrodes and the first potential-measuring electrode of the at least two potential-measuring electrodes arranged on the inner surface of the band define a first group of electrodes, the second current-injecting electrode of the at least two current-injecting electrodes and the second potential-measuring electrode of the at least two potential-measuring electrodes arranged on the outer surface of the band define a second group of electrodes, and electrodes of the first group of electrodes are aligned in a direction different from a direction in which electrodes of the second group of electrodes are aligned.

16. The bioimpedance-measuring device according to claim 14, wherein on each surface of the band, an electrode proximal to a transthoracic segment of the user is a respective potential-measuring electrode and an electrode distal to the transthoracic segment of the user is a respective current-injecting electrode.

17. The bioimpedance-measuring device according to claim 14, wherein the first current-injecting electrode of the at least two current-injecting electrodes and the first potential-measuring electrode of the at least two potential-measuring electrodes arranged on the inner surface of the band define a first group of electrodes, the first group of electrodes being aligned in a first direction along a longitudinal axis of the first arm of the user, the first current-injecting electrode of the first group of electrodes being arranged on one of a medial aspect or a lateral aspect of the wrist of the first arm of the user and the first potential-measuring electrode of the first group of electrodes being arranged on the other one of the medial aspect or the lateral aspect of the wrist of the first arm of the user.

18. The bioimpedance-measuring device according to claim 14, wherein the raw data processing system is configured so as to determine a deviation between a reference benchmark value and the obtained at least one monitoring measurement and to generate a notification for the user when the obtained at least one monitoring measurement has a value less than the reference benchmark value, and the determined deviation is between 0.25% and 2.5% of the reference benchmark value.

19. The bioimpedance-measuring device according to claim 14, wherein the raw data processing system compares the collected raw bioimpedance data with at least one limit value.

20. The bioimpedance-measuring device according to claim 14, wherein the raw data processing system is integrated into the band.

21. The bioimpedance-measuring device according to claim 14, wherein the at least two current-injecting electrodes are driven so as to use a multi-frequency current.

22. The bioimpedance-measuring device according to claim 14, wherein the band is formed by an elastic cylindrical sleeve.

23. The bioimpedance-measuring device according to claim 22, wherein the elastic cylindrical sleeve incorporates, as at least a portion of the at least two current-injecting electrodes and the at least two potential-measuring electrodes, circular electrodes.

24. The bioimpedance-measuring device according to claim 14, wherein the at least two current-injecting electrodes and the at least two potential-measuring electrodes are of different dimensions.

25. The bioimpedance-measuring device according to claim 14, wherein the band comprises at least one positioning marker for positioning the part of the second arm of the user.

26. A method for determining information relating to a transthoracic bioimpedance, the method comprising: wearing, on a wrist of a first arm of a user, a bioimpedance-measuring device; positioning a part of a second arm of the user on the bioimpedance-measuring device in order to carry out a measurement; emitting, by processing circuitry, a current flowing between at least two current-injecting electrodes, connected by a flow loop formed by contact between the bioimpedance-measuring device and, respectively, the first arm of the user wearing the bioimpedance-measuring device and the second arm of the user positioned on the bioimpedance-measuring device, the current imposed by the at least two current-injecting electrodes passing through the flow loop via a transthoracic segment of the user, a first current-injecting electrode of the at least two current-injecting electrodes being arranged on an inner surface of a band of the bioimpedance-measuring device, a second current-injecting electrode of the at least two current-injecting electrodes being arranged on an outer surface of the band of the bioimpedance-measuring device, and at least two potential-measuring electrodes arranged in the flow loop, a first potential-measuring electrode of the at least two potential-measuring electrodes being arranged on the inner surface of the band of the bioimpedance-measuring device and a second potential-measuring electrode of the at least two potential-measuring electrodes being arranged on the outer surface of the band of the bioimpedance-measuring device; obtaining, by the processing circuitry, raw bioimpedance data corresponding to a potential difference between the at least two potential-measuring electrodes; formulating, by the processing circuitry and based on the obtained raw bioimpedance data, a monitoring measurement by averaging a plurality of the obtained raw bioimpedance data; comparing, by the processing circuitry, the formulated monitoring measurement with a reference benchmark value; obtaining, by the processing circuitry and based on the comparing, information relating to the transthoracic bioimpedance; and transmitting, by the processing circuitry, the obtained information to one of the user via a user interface or to a medical representative.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0079] Other features, details and advantages of the invention will become more clearly apparent on reading the description given below by way of indication with reference to the drawings, in which:

[0080] FIG. 1 is a general view of the context of use of the measuring device according to the invention,

[0081] FIG. 2 is a flowchart of the operation of a measuring device according to the invention,

[0082] FIG. 3 is a schematic view of a measuring device according to the invention in a first embodiment,

[0083] FIG. 4 is a perspective view of a measuring device according to the invention in a second embodiment.

DETAILED DESCRIPTION OF THE INVENTION

[0084] It should first of all be noted that the figures set out the invention in detail in order to implement the invention, said figures of course being able to serve to better define the invention if necessary.

[0085] With reference first of all to FIGS. 1 and 2, the operation of the measuring device and the associated measuring method will be described. FIG. 1 shows a user 1 wearing, on a wrist 2, a bioimpedance-measuring device 3 according to the invention. The measuring device 3 takes the form of a band 4, seen here transparently through a hand of the user, the band 4 surrounding the wrist 2 of a first arm 5 of the user 1, in this case the right arm.

[0086] The band 4 of the measuring device 3 has an inner surface 21 facing the wrist 2 when the band 4 is worn by the user 1, and an outer surface 19 facing away therefrom.

[0087] The inner surface 21 carries a first current-injecting electrode 22 and a first potential-measuring electrode 23. By being worn on the wrist 2 of the user 1, this first current-injecting electrode 22 and this first potential-measuring electrode 23 are able to come into contact with the wrist 2.

[0088] The outer surface 19 carries a second current-injecting electrode 17 and a second potential-measuring electrode 18. The second current-injecting electrode 17 and the second potential-measuring electrode 18 are each configured so as to have an interface surface 56 with part 7 of the second arm 6 of the user 1, here a palm and fingers of the hand of the left arm.

[0089] When the user 1 grasps the measuring device 3, the second current-injecting electrode 17 and the second potential-measuring electrode 18 come into contact with the left hand of the user 1. Through this movement, the user 1 closes a current flow loop 8.

[0090] The band 4 comprises an electric power supply system 46 delivering a current 55 able to flow between the current-injecting electrodes when the flow loop 8 is closed. In this path, forming the flow loop 8, the current 55 passes through the first arm 5 as well as the second arm 6 of the user 1 and, between them, a transthoracic segment 9.

[0091] The current 55 then flows from the first current-injecting electrode 22 to the second current-injecting electrode 17, passing successively through the first potential-measuring electrode 23 and the second potential-measuring electrode 18.

[0092] When the current 55 flows in the flow loop 8 through the body of the user, the electrical potential value that results therefrom is dependent on the resistance encountered on the current path, this resistance varying in particular depending on the water content of the body parts passed through. A specific signal is thus delivered to the first potential-measuring electrode 23 and to the second potential-measuring electrode 18. This signal corresponds to raw bioimpedance data 48. The first potential-measuring electrode 23 and the second potential-measuring electrode 18 transmit these raw data 48 to a collection system 47 arranged on the band 4.

[0093] The collection system 47 is configured so as to communicate with a processing system 10. In the embodiment shown in FIG. 1, the processing system 10 is externalized with respect to the band 4. The collection system 47 transmits the raw data 48, via a first communication peripheral, to the processing system 10 carrying a second communication peripheral 11. The first communication peripheral and the second communication peripheral 11 communicate here by propagating the signal in the form of waves 12.

[0094] The processing system 10 applies a prerecorded algorithm to the raw data 48. According to one embodiment, the algorithm is configured so as to take an average of several consecutive raw data 48 measurements corresponding to a monitoring measurement 32, 32′ in order to obtain a result 38 that will then be compared with the floor and limit threshold values previously defined and stored in the processing system 10. The raw data 48 are thus processed in order to obtain information 50 corresponding to the comparison between the monitoring measurement 32 implementing the average of the raw data 48 and a benchmark value 52.

[0095] The information 50 is then presented to the user 1 via a user interface 13. This user interface 13 is carried by the processing system 10 in the illustrated example. The user interface 13 may make it possible to display various data, for example the information 50, the deviation 53 between the monitoring measurement 32 and the benchmark value 52, the need to perform a new monitoring measurement 32′, etc.

[0096] FIG. 2 shows a flowchart representative of an implementation of a bioimpedance-measuring device 3 according to the invention for obtaining a monitoring measurement 32.

[0097] When a user, in a step 29, activates the measuring device 3 worn on the wrist of a first arm, this measuring device is in the standby state 30. When the user forms a flow loop 8 by touching the measuring device 3 with a second arm, a monitoring measurement 32 is performed. This monitoring measurement 32 corresponds to steps 31 to 41.

[0098] The flow loop 8 is formed through a positive action by the user that creates contact between the measuring device and a first arm, via the inner surface of the band, and a second arm, via the outer surface of the band. This contact is identified by the measuring device 3 in a step 31. In a step 34, an electric power supply system 46 is driven so as to generate a current supply 55 between a first current-injecting electrode 22 and a second current-injecting electrode 17. The current 55 then flows between these two injecting electrodes in the current flow loop 8 through the body, the band also providing electrical insulation between the two injecting electrodes, which forces the current to pass through the body, successively through the first arm, a transthoracic segment and the second arm. On the current path, the current 55 emitted between each injecting electrode 17, 22 passes through the measuring electrodes 23, 18 arranged on the path, such that, in a measuring step 35, an electrical potential measurement is performed at the first measuring electrode 23 and an electrical potential measurement is performed at the second measuring electrode 18.

[0099] The electrical potential value is transferred, in a transfer step 36, from each of the measuring electrodes to a collection system 47 which, in a transmission step 37, transmits them to a processing system 10 configured so as to calculate the potential difference corresponding to the “raw data” 48.

[0100] The processing system 10, in a calculation step 39, processes the raw data 48. Firstly, each item of raw data 48 obtained, corresponding to a potential difference measurement, is compared with a recorded limit value 54, attesting to the reliability of the measurement. This limit value 54 may for example represent 150% of the reference benchmark value 52, which will be introduced below. At item of raw data 48 with a value greater than this limit value 54 implies an impedance value that is far too high and the risk of an unreliable measurement, for example due to incorrect contact conditions between the measuring device and the body of the user. It is understood that, if such unreliable measurement information should be identified, the measurement process ends and should be restarted.

[0101] The processing system 10 then compiles the raw data obtained over a given period in order to obtain a result 38 corresponding to an average of these raw data 48, said average being indicative of reliable information on the bioimpedance measurement of the user for a given day.

[0102] The result 38 obtained may be transmitted to the user on a user interface 13, in a display step 40.

[0103] The result 38 is moreover evaluated in a test step 41 by the processing system 10. The processing system 10, in the test step 41, compares the result 38 with a reference benchmark value 52 resulting from a calibration method and previously carried out and stored in a memory of the processing system 10.

[0104] The averages are calculated and stored in the memory of the processing system 10, so that the presence of an unfavorable evolution in the user's condition is identified. The result of this comparison is considered with regard to a floor value specific to the present invention. If a deviation 53 of the order of 0.25 to 2.5% is identified, with the result 38 that is less than the reference benchmark value 52, the user is warned of this on the user interface 13.

[0105] After these various successive steps, the measuring device 3 returns to the standby state 30. It remains there for a determined duration, for example two hours following a valid monitoring measurement 32, unless the user closes the current flow loop 8 beforehand. Beyond two hours after carrying out a monitoring measurement 32, the exceedance of which is monitored in step 33, an alarm 42 is triggered automatically in a step 43, iteratively, in order to warn the user of this and encourage him to perform a new monitoring measurement 32′. The alarm 42 is interrupted by a step 44 when the current flow loop 8 is formed again.

[0106] If the monitoring measurement 32 should be considered invalid, the measuring device is able to activate the alarm 42 in order to warn the user of this, inviting said user to reproduce the monitoring measurement 32.

[0107] FIG. 3 shows a bioimpedance-measuring device 3 comprising a band 4 as shown above. This band 4 in this case takes the form of an elastic cylindrical sleeve 14. The elastic cylindrical sleeve 14 extends along an axis of elongation X.

[0108] The elastic cylindrical sleeve 14 is provided with edges 15, 16 that define the ends of the sleeve along the axis of elongation X. The edge 15 is in this case called the proximal edge in that it is the edge facing the transthoracic segment of the user, whereas the edge 16 is in this case called the distal edge in that it faces away from the transthoracic segment, closest to the hand of the arm wearing the measuring device.

[0109] The elastic cylindrical sleeve 14 does not have any interruptions over its circumference, such that circular electrodes are able to be placed there, extending over the entire circumference of the elastic cylindrical sleeve 14, around the axis of elongation X of the sleeve. A first current-injecting electrode 22, forming an uninterrupted circle and shown here only in dotted lines, and a first potential-measuring electrode 23, forming an uninterrupted circle, are arranged on the inner surface 21 of the band 4 formed by the elastic cylindrical sleeve 14. It should be noted that, with these two electrodes being arranged on the inner surface 21 of the band 4, the user is not able to ensure that his body, here his wrist, is correctly in contact with the electrodes. Implementing a circular electrode makes it possible to ensure contact between the electrode and the wrist regardless of the pressure exerted by the hand closing the flow loop.

[0110] Moreover, a second current-injecting electrode 17, in this case forming a substantially circular spot, and a second potential-measuring electrode 18, in this case forming a substantially elliptical spot, are arranged on the outer surface 19 of the band 4 formed by the elastic cylindrical sleeve 14.

[0111] The first electrodes arranged on the inner face are distinguished by their position on the first arm 5 wearing the measuring device 1, with one electrode close to the proximal edge 15 and one electrode close to the distal edge 16. According to the invention, the electrode close to the proximal edge is the first potential-measuring electrode 23 and the electrode close to the distal edge is the first injecting electrode 22. The first injecting electrode 22 is thus the closest to the hand of the first arm 5 wearing the measuring device 1, and the first measuring electrode 23 is in the path of the current leaving the first injecting electrode 22.

[0112] The first current-injecting electrode 22 and the first potential-measuring electrode 23 are of the same dimensions in this case. They are arranged parallel to each other, forming a first group of electrodes in which the electrodes are aligned in a first direction X corresponding to the direction of elongation of the first arm. The electrodes are moreover also parallel to the edges 15, 16 of the elastic cylindrical sleeve 14.

[0113] The second electrodes arranged on the outer surface 19 are distinguished by their position with respect to the hand of the user resting on the measuring device, with the second injecting electrode 17 arranged so as to be in contact with the fingers of this hand and the second measuring electrode 18 arranged so as to be in contact with the palm of this hand.

[0114] The second current-injecting electrode 17 and the second potential-measuring electrode 18 have different dimensions in this case, it being notable that the second potential-measuring electrode 18 is wider than the second current-injecting electrode 17. This difference in dimensions is justified by a desire to increase the surface area of the measuring electrodes as much as possible, so that the stray impedance of the electrodes is low in comparison with the bioimpedance of the body passed through by the current, whereas the definition of the width of the injecting electrode relates only to the need for effective contact. It should be noted that this difference in dimensions has the advantage of dedicating the second measuring electrode 18, which is wider than the second injecting electrode 17, to an area in which the palm of the user should be pressed, enabling this large contact surface between the body of the user and the measuring electrode, whereas the second injecting electrode 17 is dedicated to positioning the fingers of the user.

[0115] The second electrodes form a second group of electrodes in which the second electrodes are aligned in a second direction Y corresponding to the direction of elongation of the second arm, or in other words in a direction perpendicular to the direction of elongation of the arm wearing the measuring device. As may be seen in FIG. 3 in particular, the first electrodes are arranged in series in a first direction that is perpendicular or substantially perpendicular to the second direction in which the series formed by the second electrodes extends.

[0116] The elastic cylindrical sleeve 14 consists of a weave covered with polysiloxane polymers forming the first current-injecting electrode 22 and the first potential-measuring electrode 23. The first current-injecting electrode 22 and the first potential-measuring electrode 23 have a surface structured with ribs.

[0117] The outer surface 19 of the elastic cylindrical sleeve 14 also carries a user interface 13. This user interface 13 takes the form of an electronic display device, for example a liquid-crystal screen or light-emitting diode screen.

[0118] An electric power supply system, a collection system and a processing system are supported by a printed circuit board 20, made visible transparently here so as to allow it to be identified by the reader. This printed circuit board 20 is integrated into the elastic cylindrical sleeve 14. It forms an electric power supply system 46 as has been explained above, which has a wired connection to the first current-injecting electrode 22 and the first potential-measuring electrode 23 arranged on the inner surface 21 of the elastic cylindrical sleeve 14, and to the second current-injecting electrode 17 and the second potential-measuring electrode 18 arranged on the outer surface 19, as well as to the user interface 13.

[0119] The user interface 13 and the printed circuit board 20 are located between the first current-injecting electrode 22 and the first potential-measuring electrode 23. This geometry makes it possible to comply with a spacing between the electrodes, thus avoiding interference. The geometry is also such that the presence of the user interface 13 generates a spacing between the electrodes arranged on the outer face of the elastic cylindrical sleeve 14, so as to avoid interference and to generate an adequate spacing for simultaneous contact of the palm and the fingers on their respective electrode.

[0120] The cylindrical sleeve 14 has elastic properties, allowing it to adapt to the dimensions of a user's wrist. For greater comfort of use, the printed circuit 20 will be flexible in order to adapt to an elastic cylindrical sleeve 14. For example, a flex circuit, also known by the name flex PCB, may be used. In the same way, the user interface 13 may be flexible. Failing that, the user interface 13 will preferably be profiled so as to follow a rounding in order to conform to the wrist.

[0121] FIG. 4 shows another embodiment of a bioimpedance-measuring device 3. The band 4 is provided with a clasp 26 for making overlapping ends 27, 28 interact. When the ends 27, 28 interact, the band 4 forms a closed cylinder able to be placed around the arm of the user. The clasp 26 is in this case a pin-buckle clasp, the band 4 therefore being adjustable to the dimensions of the wrist of each user.

[0122] The band 4 incorporates non-circular electrodes 17, 18, 22, 23, arranged locally on the band 4. In particular, a first current-injecting electrode 22 and a first potential-measuring electrode 23 are of different dimensions. More particularly, the first potential-measuring electrode 23, illustrated transparently, covers a surface area larger than the first current-injecting electrode 22, also illustrated transparently, in order to make the stray impedance of this measuring electrode low, as explained above. The same applies for a second current-injecting electrode 17 and a second potential-measuring electrode 18. In this exemplary embodiment, the first potential-measuring electrode 23 is of a size substantially equivalent to the second potential-measuring electrode 18.

[0123] In accordance with what has been described for the first embodiment, the electrode proximal to the transthoracic segment is the first potential-measuring electrode 23, whereas the electrode distal to the transthoracic segment is the first injecting electrode 22. The first injecting electrode 22 is thus closest to the hand of the first arm 5 wearing the measuring device 1. The first electrodes are arranged in series in a first direction X.

[0124] On the outer surface 19, intended to come into contact with in this case the hand of the second arm of the user, the electrode proximal to the transthoracic segment is the second potential-measuring electrode 18, whereas the electrode distal to the transthoracic segment is the second injecting electrode 17. The first electrodes are arranged in series in a second direction Y, substantially perpendicular to the first direction X.

[0125] The combination of these features relating to the distal/proximal positioning of the injecting and measuring electrodes is notable in this case in that the current-injecting electrodes are positioned distally on each surface of the measuring device, such that implementation of the largest possible flow loop from one injecting electrode to the other is ensured.

[0126] The electrodes carried by an inner surface 21 of the band, that is to say the first current-injecting electrode 22 and the first potential-measuring electrode 23, are elliptical in shape. The electrodes carried by an outer surface 19 of the band, that is to say the second current-injecting electrode 17 and the second potential-measuring electrode 18, take the form of the end of a finger corresponding to the distal phalanges. These are provided with positioning markers 24 corresponding to projections, for example tabs, on which a user will have to bring together two distal phalanges of his second arm. The measurement reproducibility inherent to a contact geometry will thus be ensured.

[0127] It is notable according to this embodiment that all of the electrodes, both the first electrodes arranged on the inner surface of the band and the second electrodes arranged on the outer surface of the band, are arranged in a front part of this band, that is to say the part of the band opposite the clasp. It is thereby ensured, when the user presses on the band with his free hand, that the first electrodes will be firmly pressed against the first arm wearing the measuring device.

[0128] As has been described above, the band 4 is in communication with an externalized processing system. A signal collected by the collection system 47 embedded in the band 4 and communicating with each of the potential-measuring electrodes 23, 18 is thus transmitted. This signal thus comes both from the first potential-measuring electrode 23 and from the second potential-measuring electrode 18, and corresponds to raw impedance data 48. The collection system 47 is provided with a first communication peripheral. This collection system 47 is arranged in a thickness 25 of the band 4. The first communication peripheral is configured so as to communicate with the processing system 10 carrying a second communication peripheral 11. The thickness 25 of the band 4 also contains the electric power supply system 46 connected to the four electrodes 17, 18, 22, 23.

[0129] It will be understood from reading the above that the present invention proposes a bioimpedance-measuring device configured so as to achieve a gain in terms of compactness, practicality and ease of use in comparison with existing devices. This bioimpedance-measuring device is intended to be worn continuously by a user who, through a simple action, performs a monitoring measurement in order to monitor the evolution of his lung condition. Such a bioimpedance-measuring device, using a large Piccoli vector, also achieves a gain in terms of accuracy in comparison with the prior art.

[0130] The invention should not however be limited to the means and configurations that are described and illustrated here, and it also extends to any equivalent means or configuration and to any technical combination using such means. In particular, the form of the bioimpedance-measuring device may be modified without impacting the invention, insofar as the bioimpedance-measuring device ultimately performs the same functions as those described in this document.