WO2024042227A1

WO2024042227A1 - Wearable monitoring system and method and computer program

Info

Publication number: WO2024042227A1
Application number: PCT/EP2023/073403
Authority: WO
Inventors: Helene Laurence Francoise LEFEBVRE; Mathieu CATTELAN
Original assignee: Eclypia
Priority date: 2022-08-26
Filing date: 2023-08-25
Publication date: 2024-02-29

Abstract

The wearable monitoring system for monitoring in vivo a physiological parameter in an animal body comprises: - a light emitting system (1029) with one or more Quantum Cascade LASERs which emit a light beam with at least one light beam characteristic, and a LASER controller to set the at least one light beam characteristic, - a sensor to detect a measurement signal representative of the physiological parameter, and which results from an interaction of the light beam with the animal body, - a battery (1003) to provide power to the light emitting system and to the sensor, - a mode switching controller (1005) to switch the LASER controller to one of a plurality of power consumption modes based at least on a physiological signal of the user.

Description

Wearable monitoring system and method and computer program

FIELD OF THE INVENTION

[01] The present invention relates to wearable monitoring systems, methods, and computer programs.

[02] More specifically, the invention relates to a wearable monitoring system for repeatedly sensing in vivo the concentration of an analyte in an animal body.

BACKGROUND OF THE INVENTION

[03] In the field of diabetes, it is known to use a continuous glucose monitor (“CGM”) to frequently detect a concentration of blood glucose in a human body. The most common CGMs are based on electrochemical technology. They are micro- invasively inserted into the skin of the patient, where concentration of glucose can be measured electrochemically. More precisely, they are placed in contact with the physiological fluid, and a processor is adapted to estimate concentration of blood glucose based on the detected concentration in the physiological fluid. The estimated concentration is then communicated to an external device for further treatment.

[04] However, being micro-invasive CGMs are bringing risks of infection and potential skin allergy to the patient. In addition, these CGMs need to be changed every 10 to 14 days and as such generate a lot of waste.

[05] Recently, some teams started investigating the possibility of detecting the concentration of glucose in the interstitial fluid of a human body using a non- invasive technology. This approach is described for example in “Windowless ultrasound photoacoustic cell for in-vivo mid-IR spectroscopy of human epidermis: Low interference by changes of air pressure, temperature, and humidity caused by skin contact opens the possibility for a non-invasive monitoring of glucose in the interstitial fluid”, Pleitez et al. 2013, Review of Scientific Instruments 84, Issue 8, 10.1063/1.4816723 (http://dx.doi.Org/10.1063/1.4816723). The advantages of this technology are for example to limit the risk of infection or skin allergy, and to be usable for a longer time, which is beneficial for the planet.

[06] There are huge challenges to be overcome in order to develop a fully operational wearable sensing system using this technology.

[07] One of the challenges relates to battery management.

[08] Even though battery management is a concern for many electronic portable devices (see for example US 2012/316,471 , US 2013/217,979 or “A survey of NFC sensors based on energy harvesting for loT applications”, Antonio Lazaro et al., Sensors, 2 November 2018 pp 1-26), the present type of systems with enclosed mid-IR light sources has specific energy management requirements, so that the traditional approaches of battery management can not easily apply.

[09] The inventors have been looking to determine a suitable approach for the battery management of such systems.

BRIEF SUMMARY OF THE INVENTION

[10] Thus, the invention relates to a wearable monitoring system for monitoring in vivo a physiological parameter in an animal body, wherein the wearable monitoring system comprises:

- a light emitting system comprising one or more Quantum Cascade LASERS adapted to emit a light beam with at least one light beam characteristic, and a LASER controller adapted to set said at least one light beam characteristic,

- a sensor adapted to detect a measurement signal representative of said physiological parameter resulting from an interaction of the light beam with the animal body,

- a battery adapted to provide power at least to the light emitting system and to the sensor,

- a mode switching controller adapted to switch the LASER controller to one of a plurality of power consumption modes based at least on a physiological signal of the user, wherein the average power quantities of the plurality of power consumption modes differ from one another.

[11] Thanks to these provisions, an appropriate battery management scheme can be used, which is suitable for this kind of systems.

[12] According to different aspects, it is possible to provide the one and I or the other of the characteristics below taken alone or in combination.

[13] According to one embodiment, the plurality of power consumption modes differ from one another by at least a frequency of operation of the light emitting system.

[14] According to one embodiment, the wearable monitoring system comprises a processor adapted to treat the measurement signal according to a plurality of treatment modes, wherein the battery is adapted to provide power to the processor, and wherein the mode switching controller is further adapted to switch the processor to one of the treatment modes.

[15] According to one embodiment, the wearable monitoring system comprises a display adapted to display a concentration of the analyte according to a plurality of display modes, wherein the battery is adapted to provide power to the display, and wherein the mode switching controller is further adapted to switch the display to one of the display modes. [16] According to one embodiment, the wearable monitoring system comprises a communication module adapted to communicate data outside the wearable sensing system according to a plurality of communication modes, wherein the battery is adapted to provide power to the communication module, and wherein the mode switching controller is further adapted to switch the communication module to one of the communication modes.

[17] According to one embodiment, the physiological parameter is a glucose concentration or a heart rate.

[18] According to one embodiment, the sensor is a first sensor, the wearable monitoring system further comprising a second sensor.

[19] According to one embodiment, the second sensor is adapted to operate under a plurality of sensing modes to detect a second measurement signal, wherein the battery is adapted to provide power to the second sensor, and wherein the mode switching controller is further adapted to switch the second sensor to one of the sensing modes.

[20] According to one embodiment, the mode switching controller is adapted to switch the LASER controller to one of a plurality of power consumption modes based also on a signal from the second sensor.

[21] According to one embodiment, the mode switching controller is adapted to switch the LASER controller to one of a plurality of power consumption modes based also on user input.

[22] According to one embodiment, the mode switching controller is adapted to switch the LASER controller to one of a plurality of power consumption modes based on the measurement signal.

[23] According to one embodiment, the mode switching controller is adapted to switch the LASER controller to one of a plurality of power consumption modes based on a value and/or a trend of the measurement signal.

[24] According to one embodiment, the mode switching controller is userspecific customized.

[25] According to one embodiment, the mode switching controller is adapted to switch the LASER controller to one of three or more power consumption modes.

[26] According to one embodiment, the wearable monitoring system further comprises a determination module adapted to determine the physiological parameter based on a first measurement signal obtained from a first light beam with a first light beam characteristic and on a second measurement signal obtained from a second light beam with a second light beam characteristic, and the mode switching controller is adapted to switch the LASER controller by altering at least one of the first and second characteristics.

[27] According to one embodiment, said at least one of the first and second characteristics is a time duration between the emission of the first beam and the emission of the second beam.

[28] According to one embodiment, said at least one of the first and second characteristics is a value of modulation frequency of the first beam.

[29] According to one embodiment, said at least one of the first and second characteristics is a number of modulation frequencies of the first beam.

[30] According to one embodiment, said at least one of the first and second characteristics is a number of wavelengths of the Quantum Cascade LASERS.

[31] According to one embodiment, the determination module is adapted to determine the physiological parameter based on a comparison of the second measurement signal and the first measurement signal, and wherein the mode switching controller is adapted to switch the LASER controller by altering the frequency of activation of the first beam only.

[32] According to another aspect, the invention relates to a monitoring method for monitoring in vivo a physiological parameter in an animal body with a wearable monitoring system, wherein:

- a battery provides power at least to a light emitting system and to a sensor,

- one or more Quantum Cascade LASERS of the light emitting system emit a light beam with at least one light beam characteristic, set by a LASER controller,

- the sensor detects a measurement signal representative of said physiological parameter resulting from an interaction of the light beam with the animal body,

- a mode switching controller switches the LASER controller to one of a plurality of power consumption modes based at least on a physiological signal of the user, wherein the average power quantities of the plurality of power consumption modes differ from one another.

[33] According to another aspect, the invention relates to a computer program comprising instructions to cause a wearable monitoring system to execute the steps of this method.

BRIEF DESCRIPTION OF THE DRAWINGS

[34] Embodiments of the invention will be described below with reference to the drawings, described briefly below:

[35] Fig. 1 represents an animal wearing a continuous glucose monitor.

[36] Fig. 2 is a schematical sectional view of a continuous glucose sensor monitor. [37] Fig. 3 is a time graph showing evolution of a physiological parameter with time, and the associated energy consumption mode.

[38] Fig. 4 is a time graph showing evolution of a physiological parameter with time, and the associated energy consumption mode.

[39] Fig. 5 is an organigram of determination of the energy consumption mode according to one embodiment.

[40] Fig. 6 is a block diagram of the sensing system.

[41] Fig. 7 is a time graph of intensity of emitted light in a first energy consumption mode.

[42] Fig. 8 is a time graph of intensity of emitted light in a second energy consumption mode.

[43] In the drawings, identical references designate identical or similar objects.

DETAILED DESCRIPTION OF THE INVENTION

[44] The invention relates to an in-vivo physiological parameter monitor. In particular, it relates to a biological analyte monitor. It will be described below according to an in-vivo continuous glucose monitor of a human. However, the invention may also be used on other animal users than humans. According to the invention, “animal” encompasses “human”. The invention may also be used for other physiological parameters than blood glucose.

[45] Fig. 1 schematically represents a human 1001 with a sensing system 1010. The sensing system 1010 is worn by the human 1001. It is therefore in contact or in close proximity with the body of the human 1001. The sensing system 1010 encompasses one or more detection systems adapted to detect one or more physiological parameters according to various technologies. According to a first embodiment, the sensing system 1010 comprises at least a continuous glucose monitor 1002. This sensing system 1010 may comprise additional detection systems, as will be described below. Further, the sensing system 1010 may comprise components which are common to a plurality of detection systems, such as, for example, the housing, the battery, etc...

[46] A continuous glucose monitor 1002 repeatedly provides a measurement of blood glucose in the human body. The measurement is repeated from time to time, for example in the order of minutes. The continuous glucose monitor 1002 is continuously worn during that time. For example, it is adhered to the skin of the patient, or otherwise fixed to, for typically one hour or more. The repetition of the measurement is automated. The user does not have to perform any action to repeat the measurement. The continuous glucose monitor 1002 is adapted to measure a concentration of glucose in the interstitial fluid. The concentration of glucose in blood may be determined by processing the measured concentration of glucose in the interstitial fluid.

[47] According to one embodiment, the continuous glucose monitor 1002 is an optical glucose monitor 1002. This enables to monitor blood glucose non-invasively (in any case without any mechanical perforation of the skin).

[48] Fig. 2 schematically shows part of the sensing system 1010, and in particular, part of a continuous glucose monitor 1002 according to one embodiment. The continuous glucose monitor 1002 comprises a housing 1026 which houses various components useful for detection. Said housing 1026 has a bottom side 1007 which is oriented toward the user 1001 , the bottom side 1007 may also be called a sensing side. The continuous glucose monitor 1002 comprises a light emitting system 1029, such as comprising a light source. In particular, the light source comprises one or more Quantum Cascade LASER (“QCLs”) adapted to emit a suitable light toward the user, in particular in the mid-infra-red (“MIR”) range. The light emitting system 1029 comprises a LASER controller 1030 adapted to tune the LASER according to the specific requirements for the measurement. The specific requirements may comprise a spectrum of the emitted light beam, a duration of light emission, a peak power or a duty cycle. The light will exit the housing 1026 at an emission region 1027 on the bottom side 1007 of the housing 1026, and enter into the user. The interaction of the light with the user will cause emission of a thermal wave, which is emitted from the user, and in particular at least partly toward the continuous glucose monitor 1002. When the emitted light is properly tuned, the characteristics of the thermal wave depend at least on the concentration of the metabolite of interest inside the body of the user. The continuous glucose monitor 1002 further comprises a thermal regulation system 1011. The thermal regulation system 1011 is adapted to regulate the temperature of the light emitting system 1029. For example, the thermal regulation system 1011 comprises a Peltier module.

[49] In some embodiments, the continuous glucose monitor 1002 may comprise a cavity 1035 with an opening 1028 in the bottom side 1007 of the housing 1026, the thermal wave propagating inside the cavity as an acoustic wave. The cavity 1035 is in acoustic communication with a microphone 1031 adapted to detect the propagation of the acoustic wave, and convert the detected wave into an electrical signal for treatment. This may be achieved through a channel 1036 linking the cavity 1035 and the microphone 1031.

[50] The sensing system 1010 further comprises a battery 1003. The battery 1003 is electrically connected to the other electrical components of the sensing system 1010 to provide power to these electrical components. According to one embodiment, as shown, the battery 1003 may be provided inside the housing 1026. However, the battery 1003 may be provided in another housing, which may be wearable, and wiredly electrically connected to the housing 1026.

[51] In particular, the battery 1003 provides power to the light emitting system 1029. The battery 1003 provides power to the LASER controller 1030 so that it can process information to control the LASER 1012 and determine at least one light beam characteristic for the LASER beam. The battery 1003 provides power to the LASER 1012 so that it may emit a light beam with the determined light beam characteristic. The battery 1003 provides power to the microphone 1031 , so that it can detect, process and store a measurement signal.

[52] In order to determine one value for the physiological parameter in the animal body using a QCL-based light emitting system, it is necessary to emit a plurality of successive incident light waves at different modulation frequencies, and spaced from one another in time. In particular, the successful determination must be performed by measuring in a given layer of the skin, the depth of which, with respect to the position of the sensor, may vary in time for various reasons. The depth of a measurement will typically depend on the modulation frequency of the emitted light beam. The successful determination would therefore imply the determination of a set of one or more instantly appropriate modulation frequencies. These may be determined based on prior measurements. The measurement is then performed using this determined set of appropriate modulation frequencies to determine the value for the physiological parameter. A suitable method is for example described in WO 2023/031,243 by the applicant, which is hereby incorporated by reference in its entirety for all purposes.

[53] According to one embodiment, the sensing system 1010 may comprise a user interface. The user interface is adapted for a user to enter information into the sensing system 1010, and/or for the sensing system 1010 to provide information to a user. According to one embodiment, the battery 1003 may provide power to the user interface. According to one embodiment, the user interface comprises a digital screen which is attached to the housing 1026 and may be used to display information to the user. This digital screen may be a touch screen enabling the user to provide information to the sensing system 1010. Other systems to enter information may also be used, such as buttons. In alternative or in addition, the user interface may comprise a communication module 1004 adapted to communicate information with the outside. The communication module 1004 is for example a wireless communication module. One may for example use a Bluetooth communication module such as it exists at the earliest priority date of the present patent application. The communication module 1004 may communicate with a smartphone of the user, thereby receiving information from the smartphone of the user and/or sending information to the smartphone of the user. The user interface of the smartphone may be used by the user to enter/provide information.

[54] The battery 1003 may be removable and/or rechargeable.

[55] The sensing system 1010 may also comprise a data storage.

[56] The sensing system 1010 may be operated under a plurality of power consumption modes.

[57] Each power consumption mode may be characterised by the average power it consumes.

[58] For example, the sensing system 1010 may be operated under a first energy consumption mode M1 which consumes an average power P1 , and under a second energy consumption mode M2 which consumes an average power P2. P1 differs from P2. P1 is sufficiently different from P2 so that a person skilled in the art may recognize that the two modes are different energy consumption modes. For example, P1 differs from P2 by at least 10 %.

[59] According to one embodiment, the LASER controller 1030 may alternatively take a plurality of power consumption modes. According to a given power consumption mode Mi, the LASER controller 1030 will cause the LASER beam to be emitted at average power Pi, where “i” designates an integer indicia ranging from 1 to n. Because the LASER controller 1030 will cause a light beam to be emitted from time to time, the average power of an energy consumption mode is determined on an interval of time which is sufficiently long for the average power of the mode to be constant over time. This interval of time will comprise at least one period of the measurement cycle, i.e. comprising a time where light is emitted and a time where light is not emitted.

[60] The sensing system 1010 comprises a mode switching controller 1005 adapted to switch the LASER controller 1030 to one of the plurality of power consumption modes.

[61] For example, if the LASER controller 1030 is set to control emission of light to perform a determination every ns seconds, the number ns of seconds may be different for the different energy consumption modes. Hence, if the instantaneous power consumption of the LASER is the same, the average power of the modes will differ from one another because the LASER 1012 is activated more or less often. According to an example, a power consumption mode may use a parameter ns=ns1 taken between 60 and 300 seconds, and another consumption mode may use a parameter ns=ns2 taken between 200 and 1200 seconds. ns2 is greater than ns1 by at least 60 seconds, notably by at least 180 seconds, for example by at least 600 seconds.

[62] The frequency of operation of the LASER 1012 is the inverse of the period ns of switching on the LASER 1012. It is a different parameter from the frequency of the LASER 1012 itself.

[63] According to another example, a measurement may need a plurality of subsequent light beams to be emitted. For example, a measurement will need a first and a second successive light beams with different emission parameters, so that the determination of the physiological parameter will be based on the signals obtained for these two measurements, in particular on the comparison of the signals obtained for these two measurements. The average power of the power consumption modes may differ by altering at least one of the emission parameters. For example, the average power of the power consumption modes may differ because the LASER for the first light beam may be activated more or less often, and the activation of the LASER for the second beam may depend on the activation for the first beam. According to another variant, only the frequency of activation for the first beam may be altered. This means that, in a lower energy consumption mode, the measurement signal obtained after activating the LASER with the second light beam will be associated with an older measurement signal obtained after activating the LASER with the first light beam.

[64] Fig. 7 is a time graph of LASER emission in a first energy consumption mode (low energy consumption mode). As can be seen on Fig. 7, during the represented time, up to three determinations of the parameter of interest are performed. Each determination period T comprises an active time Ta during which determination is performed and a passive time Td. During the active time Ta, a measurement is performed at a previously determined instantly relevant modulation frequency. The previously determined instantly relevant modulation frequency was determined by a previous light beam emission. The determination period T is typically between 5 minutes and one hour, notably between 10 minutes and 30 minutes. The active time is typically between 10 seconds and 200 seconds, notably between 50 seconds and 150 seconds.

[65] Fig. 8 is a time graph of LASER emission in a second energy consumption mode (high energy consumption mode). As a comparison with the low energy consumption mode:

- during the active time Ta, a plurality of i LASER emissions at different modulation frequencies fi, ...

are performed, and the determination is performed based on these measurements. Thus, the instantly relevant modulation frequency will be determined with better precision - the number of modulation frequencies is higher in the high energy consumption mode, and the duration of time between the determination of the instantly relevant modulation frequency and the determination of the physiological parameter is shorter;

- a plurality of QCLs of different wavelengths L1, L2, , LX may be used, which will provide a more precise value for the determined parameter - the number of LASER wavelengths is higher in the high energy consumption mode;

- the determination period T is shortened in the high energy consumption mode, which will provide more measurements of the determined parameter.

[66] The determination period T is typically between 2 minutes and 20 minutes, notably between 4 minutes and 10 minutes. The active time is typically between 100 seconds and 500 seconds, notably between 150 seconds and 300 seconds.

[67] Hence, in the examples above, the light beam characteristics which are made to differ between the energy consumption modes are the number of different modulation frequencies, the number of QCLs of different wavelengths, and/or the duration and/or duty cycle of the determination period.

[68] Even though three differences are shown here between the low and high energy consumption modes, this is illustrative only, and, alternatively, one may use only one or two of the above differences when switching from one energy consumption mode to another.

[69] The mode switching controller 1005 is adapted to alter the power consumption mode. The determination of the power consumption mode may be based on the detected signal.

[70] In other words, the mode switching controller 1005 takes as entry at least the detected signal, and outputs a control to switch power consumption mode (or not).

[71] According to an example, a control parameter for the mode switching controller 1005 is the latest measured (or estimated) value of the physiological parameter, in particular of the concentration of blood glucose G. This value is compared to a target range. If the measured value is inside the target range, the mode switching controller 1005 controls the LASER controller 1030 to a lower power consumption mode. If the measured value is outside the target range, the mode switching controller 1005 controls the LASER controller 1030 to a higher power consumption mode. The target range may be predefined, constant and/or user- parametered. For example, the target range corresponds to a normo-glycemia that the user is supposed to experience. Being outside the target range may mean the user is likely facing hypo- or hyper-glycemia. [72] According to an example, a control parameter for the mode switching controller 1005 is the latest trend of blood glucose AG. This trend may be determined based on two or more past measurement values. This trend is compared to a trend target range. If the measured trend is inside the trend target range, the mode switching controller 1005 controls the LASER controller 1030 to a lower power consumption mode. If the measured trend is outside the trend target range, the mode switching controller 1005 controls the LASER controller 1030 to a higher power consumption mode. The trend target range may be predefined, constant and/or user-parametered. For example, the trend target range indicates that the glycemia of the user is stable. Being outside the trend target range may mean the user is facing a fast change of glycemia, which may lead to hypo-glycemia or hyper-glycemia.

[73] According to an example, the control parameter for the mode switching controller 1005 is a bi-dimensional vector comprising the blood glucose concentration G as described above and the blood glucose trend AG as detailed above.

[74] The power consumption mode is determined based on the value and trend of glycemia.

[75] For example, a lower energy consumption mode may be used at or around normo-glycemia. A lower energy consumption mode may be used at high glycemia with a decreasing trend. A lower energy consumption mode may be used at low glycemia with an increasing trend. A higher energy consumption mode may be used in the other cases.

[76] The glycemia interval may be dealt in three or more zones ranging from severe hypoglycemia to severe hyperglycemia. The interval for trend may be dealt in three or more zones from fast decrease to fast increase. This leads to nine or more combinations of glycemia and glycemia trend, to each of which an energy consumption mode may be set.

[77] It is possible to define more than two energy consumption modes and, in particular, more than three energy consumption modes, and to predefine a table in which an energy consumption mode is assigned to each case of the double-entry table.

[78] According to an embodiment, the sensing system 1010 comprises a processor 1006 adapted to treat the measured signal in order to determine the concentration of metabolite. The processor 1006 may implement a plurality of computerized treatment modules, each treatment implementing a different signal treatment in order to determine the concentration of metabolite. The plurality of treatment modules may consume different quantities of energy and provide a more or less accurate response. For example, a first treatment module consuming a high quantity of energy may provide a more accurate estimation than a second treatment module consuming a low quantity of energy. For example, the first treatment module may comprise more layers of neural network than the second treatment module.

[79] According to this embodiment, the mode switching controller 1005 may control the processor 1006 to use one of the above treatment modules based on the detected signal, in order to control the power consumption mode.

[80] For example, if the past concentration of metabolite is average and steady, the mode switching controller 1005 may use a low energy consumption treatment module to determine a value of the metabolite, whereas, if the past concentration of metabolite is high or low and/or rapidly changing, the mode switching controller 1005 may use a high energy consumption treatment module to determine a value of the metabolite.

[81] As described above, the sensing system 1010 may comprise a display 1008 which communicates metabolite information to the user. According to an embodiment, the display 1008 may be operated under a variety of power consumption modes. According to one mode, the display operates at a high energy consumption mode while, according to another mode, the display 1008 operates at a low energy consumption mode. For example, in the high energy consumption mode, the latest measurement is permanently displayed, so that it can be readily read by the user upon looking at the display while, in the low energy consumption mode, the display may display the metabolite concentration only upon request from the user (for example operating a dedicated push-button), and is turned off the rest of the time.

[82] According to this embodiment, the mode switching controller 1005 may control the display 1008 to use one of the above display modes based on the detected signal, in order to control the power consumption mode.

[83] For example, if the past concentration of metabolite is average and steady, the mode switching controller 1005 may use a low energy consumption display mode to display a value of the metabolite only upon request, whereas, if the past concentration of metabolite is high or low and/or rapidly changing, the mode switching controller 1005 may use a high energy consumption display mode to display a value of the metabolite at all time.

[84] As described above, the sensing system 1010 may comprise a communication module 1004 adapted to communicate data with an external device. According to one embodiment, the communication module 1004 may use a plurality of communication modes which consume different average power quantities. For example, the communication module 1004 may implement a plurality of communication technologies enabling for example different ranges of communication, but also consuming different levels of energies. For example, the communication module 1004 may be adapted to communicate using a Bluetooth communication protocol to a close- by terminal, and using a wi-fi protocol to a further away communication device.

According to yet another example, the communication module 1004 may be set to emit communications to the outer world at a settable communication frequency. If the communication module 1004 is set to a frequent communication mode where it frequently communicates to the outer world, it consumes more average power than under a scarce communication mode wherein it communicates less frequently to the outer world.

[85] According to this embodiment, the mode switching controller 1005 may control the communication module 1004 to use one of the above communication modes based on the detected signal, in order to control the power consumption.

[86] For example, if the past concentration of metabolite is average and steady, the mode switching controller 1005 may use a low energy consumption communication mode to communicate a value of the metabolite only to a close-by terminal and/or less frequently. If the past concentration of metabolite is high or low and/or rapidly changing, the mode switching controller 1005 may use a high energy consumption communication mode to communicate a value of the metabolite more frequently and/or to a remote device (for example to reach a remote emergency server).

[87] For example, if the processor 1006 triggers an alert, in a lower energy consumption mode, communication may be performed only in cases of alerts.

[88] According to one embodiment, the sensing system 1010 comprises a second sensor 1009. For example, the second sensor 1009 uses a different technology, and for example it does not use a LASER. The second sensor 1009 may be used to detect a physiological parameter of the user, which is different from the one described above.

[89] Using the second sensor 1009 might provide useful information to the patient, but consumes energy. Therefore, according to this embodiment, according to a higher energy consumption mode, the second sensor 1009 is operated whereas, according to a lower energy consumption mode, the second sensor 1009 is not operated. The second sensor 1009 may be operated in two or more different modes, with different power consumptions.

[90] According to this embodiment, the mode switching controller 1005 may control the operation mode of the second sensor 1009 based on the detected signal, in order to control the power consumption.

[91] For example, if the past concentration of metabolite is average and steady, the mode switching controller 1005 may use a higher energy consumption mode for the second sensor 1009 to take this opportunity to use available power to obtain more information about the user. If the past concentration of metabolite is high or low and/or rapidly changing, the mode switching controller 1005 may use a lower energy consumption mode for the second sensor 1009 in order to focus the available power on the main sensor.

[92] According to an embodiment, when the sensing system comprises a second sensor 1009, as described above, the mode switching controller 1005 may also use the signal from the second sensor 1009 to determine the energy consumption mode.

[93] According to an example, the control parameter for the mode switching controller 1005 is a bi-dimensional vector comprising a value related to blood glucose obtained by the continuous glucose monitor 1002 as described above and the signal from the second sensor 1009.

[94] The power consumption mode is determined based on values from these two sensors.

[95] For example, a measurement by the second sensor 1009 may determine a rule to be applied by the mode switching controller 1005 based on glucose measurement.

[96] One example below will be given when the second sensor 1009 measures a physical activity of the user. For example, the sensing system 1010 comprises a photoplethysmograph as the second sensor 1009. The photoplethysmograph is used to determine the cardiac rate of the user. According to one embodiment, if the cardiac rate of the user is average, the mode switching controller 1005 may control the LASER controller 1030 to operate under a lower energy consumption mode. If the cardiac rate of the user is high, the mode switching controller may control the LASER controller 1030 to operate under a higher energy consumption mode. In particular, it may be desired to take more frequent measurements of blood glucose in case of high cardiac rate, since blood glucose may change more rapidly in such cases. “Low” or “high” may be determined by comparison with a predefined threshold which may be user-dependent.

[97] Fig. 3 shows an example of using the above system.

[98] Fig. 3 is a graph showing the measured heart rate (“HR”) of a user along time (“t”). The user has a predefined average heart rate set to 90 beats per minute (“bpm”). At to=O, the user is in normo-glycemia and has a heart rate close to average (“RAHR”), so that the LASER controller 1030 is set to a low energy consumption mode (“Eco”) such as, for example, shown on Fig. 7. Heart rate is measured frequently, for example every few seconds. As long as the heart rate remains below the predefined threshold, the energy consumption mode is not changed. At ti =4,8 min, heart rate is detected as above a predefined threshold, so that the mode switching controller 1005 is set to a higher energy consumption mode (“Std”) such as, for example, shown on Fig. 8. For example, under the higher consumption mode, blood glucose is measured more often, or more accurately. As long as the heart rate remains above the predefined threshold, the energy consumption mode is not changed. At ti =7,4 min, heart rate is detected as below a predefined threshold, so that the mode switching controller 1005 is set to a lower energy consumption mode. As long as the heart rate remains below the predefined threshold, the energy consumption mode is not changed. One may also set a minimum amount of time during which the sensing system 1010 will remain in a given energy consumption mode. Thus, after switching energy consumption mode, the mode switching controller 1005 will not be activated during a predetermined amount of time.

[99] As discussed above, this scenario might be based on the measured signal from the second sensor 1009 only. Alternatively, the above scenario may be impacted by the blood glucose of the user. For example, depending on the measured blood glucose, the heart rate thresholds for switching energy consumption mode may differ.

[100] The above example corresponds for example to a walking cycle of a user including climbing stairs. According to this example, the sensing system will spend 63% of time in a low energy consumption mode.

[101] Fig. 4 is a graph showing the measured heart rate (“HR”) of a user along time (“t”). The user has a predefined average heart rate (“RHR”) set to 85 beats per minute (“bpm”). At to=O, the user is in normo-glycemia and has a highly increasing trend S2 for the heart rate, so that the LASER controller 1030 is set to a high energy consumption mode. Heart rate is measured frequently, for example every few seconds. As long as the heart rate trend remains higher than a predefined threshold (“S1”), the energy consumption mode is not changed. For example, under the higher consumption mode, blood glucose is measured more often, or more accurately. At ti =35 min, the heart rate is detected as steady (the heart rate trend is detected as close to zero), so that the mode switching controller 1005 is set to a lower energy consumption mode (“Eco”). As long as the heart rate trend remains close to zero, the energy consumption mode is not changed. At ti = 188 min, the heart rate is detected as having a high absolute value (in fact, the heart rate is quickly decreasing), so that the mode switching controller 1005 is set to a higher energy consumption mode. As long as the heart rate trend keeps a high absolute value, the energy consumption mode is not changed. The above scheme is reproduced along time, leading to a time interval from ti=188 min to t2=341 min in higher energy consumption mode (“Std”), a time interval from t2=341 min to ts=426 min in lower energy consumption mode, a time interval from ts=426 min to t4=443 min in higher energy consumption mode, a time interval from t4=443 min to ts=494 min in lower energy consumption mode, a time interval from ts=494 min in higher energy consumption mode, The duration time of each time interval is shown just above each window.

[102] The above scenario may be impacted by the blood glucose of the user. For example, depending on the measured blood glucose, the heart rate thresholds for switching energy consumption mode may differ.

[103] The above example corresponds for example to a running cycle of a user doing an ultra-trail. According to this example, the sensing system will spend 44% of time in a low energy consumption mode.

[104] As described above, a physiological signal of the user may be used to determine the energy consumption mode. The physiological signal may be derived from the concentration of the metabolite of interest, may be the heart rate of the user, and/or other physiological signals such as user’s oxygen saturation on blood, bioelectrical skin impedance, galvanic skin response, skin temperature or hygrometry, or even user displacement signals such as determined by inertia measurement units.

[105] According to one embodiment, the system comprises a user interface enabling the user to control the mode switching controller 1005. The user interface may be part of the sensing system 1010, but may be integrated in a remote electronic device, such as the above system comprises the sensing system 1010 and this remote electronic device. For example, the user interface allows the user to set a preference for the operation of the mode switching controller 1005. For example, the user may define that the mode switching controller may operate in automatic mode as described above. Alternatively, the user may disable the mode switching controller 1005 and set a given energy consumption mode. For example, the user may set a low energy consumption mode. This would be the case for example if the user knows that they will not be able to recharge or exchange the battery for a long time. For example, the user may set a high energy consumption mode. This would be the case for example if the user knows that they will be able to shortly recharge or exchange the battery, and that they want the sensing system 1010 to be fully operational up to that time.

[106] According to an embodiment, available power at the battery 1003 may be an input parameter for the mode switching controller 1005. For example, if the available power is less than a predefined threshold, the mode switching controller 1005 is disabled, and the system is set to use a lower energy consumption mode. [107] According to an embodiment, a wearing sensor may be an input parameter for the mode switching controller 1005. The wearing sensor provides a piece of information that the wearable sensing system 1010 is being worn. For example, if the wearing sensor detects that the wearable sensing system 1010 is not worn, the mode switching controller 1005 is disabled, and the system is set to use a lower energy consumption mode.

[108] The wearing sensor may for example use a proximity sensor adapted to detect a close-by skin of the user, and/or accelerometers and/or gyrometers to determine that the user is moving.

[109] Fig. 5 schematically shows an example of an energy mode switching process implemented by the sensing system 1010. Initially, the sensing system 1010 is in a starting energy mode 100. At any time, the sensing system 1010 will implement a step of expecting a manual user input 101 , the manual user input corresponding to a request from the user to switch to a specific power mode. Upon receiving manual user input 102, the sensing system 1010 performs a first step of switching energy consumption mode 103 consisting of switching to the specific mode requested during the receiving manual user input step. This will result in an updated energy consumption mode 111. If no manual input is received, 104, the sensing system 1010 will perform a step of applying automatic energy mode determination process 105.

[110] In parallel, the sensing system will perform a step of determining whether context information will set the energy consumption mode 106. As shown in 107, if there is determination of a specific context needing a specific energy consumption mode (for example, a detection that the sensing system 1010 is not worn), the sensing system 1010 performs a second step of switching energy consumption mode 108 by switching to this specific energy consumption mode. This will result in an updated energy consumption mode 111. If not, as shown in 109, the sensing system 1010 will perform the step of applying automatic energy mode determination process by a third step of switching energy consumption mode 110. This will result in an updated energy consumption mode 111.

[111] As can be seen from the description above, energy consumption mode switching is not only switching the LASER controller 1030 from a higher energy consumption mode to a lower energy consumption mode, it may also control switching from a lower energy consumption mode to a higher energy consumption mode.

[112] According to an example, a lower energy consumption mode may imply switching off one or more electronic components of the sensing system 1010.

[113] While exemplary embodiment of the invention has been described with reference to two main embodiments, it will be understood by those skilled in the art that various changes, omissions and/or additions may be made, and equivalents may be substituted for elements thereof without departing from the spirit and scope of the invention. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the invention without departing from the scope thereof. Therefore, it is intended that the invention is not limited to the particular embodiment disclosed as the best mode contemplated for carrying out this invention, but that the invention will include all embodiments falling within the scope of the appended claims. Moreover, unless specifically stated any use of the terms first, second, etc. do not denote any order or importance, but rather the terms first, second, etc. are used to distinguish one element from another.

LIST OF REFERENCE SIGNS

1001 : Human

1002: continuous glucose monitor

1003: battery

1004: communication module

1005: mode switching controller

1006: processor 1007: bottom side 1008: display 1009: second sensor 1010: sensing system 1011: thermal regulation system 1012: LASER 1026: housing 1027: emission region 1028: opening

1029: light emitting system

1030: LASER controller

1031: microphone

1035: cavity

1036: channel

101 : expecting a manual user input

102: receiving manual user input

103: first switching energy consumption mode

104: no received manual user input

105: applying automatic energy mode determination process

106: determining whether context information will set energy consumption mode : determination of a specific context : second switching energy consumption mode: no determination of a specific context : third switching energy consumption mode: Updated energy consumption mode

Claims

1. Wearable monitoring system for monitoring in vivo a physiological parameter in an animal body, wherein the wearable monitoring system comprises:

- a light emitting system (1029) comprising one or more Quantum Cascade LASERS adapted to emit a light beam with at least one light beam characteristic, and a LASER controller adapted to set said at least one light beam characteristic,

- a sensor adapted to detect a measurement signal representative of said physiological parameter resulting from a thermal wave caused by an interaction of the light beam with the animal body,

- a battery (1003) adapted to provide power at least to the light emitting system and to the sensor, characterized in that the wearable monitoring system comprises :

- a mode switching controller (1005) adapted to switch the LASER controller to one of a plurality of power consumption modes based at least on a physiological signal of the user, wherein the average power quantities of the plurality of power consumption modes differ from one another.

2. Wearable monitoring system according to claim 1 , wherein the plurality of power consumption modes differ from one another by at least a frequency of operation of the light emitting system.

3. Wearable monitoring system according to claim 1 or 2, further comprising a processor (1006) adapted to treat the measurement signal according to a plurality of treatment modes, wherein the battery (1003) is adapted to provide power to the processor (1006), and wherein the mode switching controller (1005) is further adapted to switch the processor (1006) to one of the treatment modes.

4. Wearable monitoring system according to any of claims 1 to 3, further comprising a display (1008) adapted to display a concentration of the analyte according to a plurality of display modes, wherein the battery (1003) is adapted to provide power to the display (1008), and wherein the mode switching controller (1005) is further adapted to switch the display to one of the display modes.

5. Wearable monitoring system according to any of claims 1 to 4, further comprising a communication module (1004) adapted to communicate data outside the wearable sensing system according to a plurality of communication modes, wherein the battery (1003) is adapted to provide power to the communication module, and wherein the mode switching controller (1005) is further adapted to switch the communication module to one of the communication modes. earable monitoring system according to any of claims 1 to 5, wherein the physiological parameter is a glucose concentration or a heart rate. earable monitoring system according to any of claims 1 to 6, wherein the sensor is a first sensor, the wearable monitoring system further comprising a second sensor (1009). earable monitoring system according to claim 7, wherein the second sensor (1009) is adapted to operate under a plurality of sensing modes to detect a second measurement signal, wherein the battery (1003) is adapted to provide power to the second sensor (1009), and wherein the mode switching controller (1005) is further adapted to switch the second sensor to one of the sensing modes. earable monitoring system according to claim 7 or 8, wherein the mode switching controller (1005) is adapted to switch the LASER controller to one of a plurality of power consumption modes based also on a signal from the second sensor. Wearable monitoring system according to any of claims 1 to 9, wherein the mode switching controller (1005) is adapted to switch the LASER controller to one of a plurality of power consumption modes based also on user input. Wearable monitoring system according to any of claims 1 to 10, wherein the mode switching controller (1005) is adapted to switch the LASER controller to one of a plurality of power consumption modes based on the measurement signal. Wearable monitoring system according to any of claims 1 to 11, wherein the mode switching controller (1005) is adapted to switch the LASER controller to one of a plurality of power consumption modes based on a value and/or a trend of the measurement signal. Wearable monitoring system according to any of claims 1 to 12, wherein the mode switching controller (1005) is user-specific customized. Wearable monitoring system according to any of claims 1 to 13, wherein the mode switching controller (1005) is adapted to switch the LASER controller to one of three or more power consumption modes.

15. Wearable monitoring system according to any of claims 1 to 14, further comprising a determination module adapted to determine the physiological parameter based on a first measurement signal obtained from a first light beam with a first light beam characteristic and on a second measurement signal obtained from a second light beam with a second light beam characteristic, and wherein the mode switching controller (1005) is adapted to switch the LASER controller by altering at least one of the first and second characteristics.

16. Wearable monitoring system according to claim 15, wherein said at least one of the first and second characteristics is a time duration between the emission of the first beam and the emission of the second beam.

17. Wearable monitoring system according to claim 15 or 16, wherein said at least one of the first and second characteristics is a value of modulation frequency of the first beam.

18. Wearable monitoring system according to any of claims 15 to 17, wherein said at least one of the first and second characteristics is a number of modulation frequencies of the first beam.

19. Wearable monitoring system according to any of claims 15 to 18, wherein said at least one of the first and second characteristics is a number of wavelengths of the Quantum Cascade LASERS.

20. Wearable monitoring system according to claim 15, wherein the determination module is adapted to determine the physiological parameter based on a comparison of the second measurement signal and the first measurement signal, and wherein the mode switching controller (1005) is adapted to switch the LASER controller by altering the frequency of activation of the first beam only.

21. A monitoring method for monitoring in vivo a physiological parameter in an animal body with a wearable monitoring system, wherein:

- a battery (1003) provides power at least to a light emitting system and to a sensor,

- the sensor detects a measurement signal representative of said physiological parameter resulting from an interaction of the light beam with the animal body, characterized in that the sensing method comprises :

- a mode switching controller (1005) switches the LASER controller to one of a plurality of power consumption modes based at least on a physiological signal of the user, wherein the average power quantities of the plurality of power consumption modes differ from one another.

22. A computer program comprising instructions to cause a wearable monitoring system to execute the steps of the method of claim 21.