# US 10,368,794 B2 · System for the remote monitoring of the hydration status of a living being > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,368,794 B2 - Document ID: US10368794B2 - Status: Granted - Kind: B2 - Application number: 14/840,852 - Filed: 2015-08-31 - Published: 2016-03-03 - Granted: 2019-08-06 - Earliest claimed: 2014-08-29 - Assignees: Ecole Polytechnique Federale De Lausanne (Epfl) - Applicants: Ecole Polytechnique FéDéRale De Lausanne (Epfl) - Inventors: Mihai Adrian Ionescu; Hoël Guerin - Web page: https://patentgrep.com/patent/US10368794B2 ## CPC - A61B 5/443: {Evaluating skin constituents, e.g. elastin, melanin, water} - A61B 5/0002: {Remote monitoring of patients using telemetry, e.g. transmission of vital signals via a communication network (endoradiosondes A61B5/07)} - A61B 5/01: Measuring temperature of body parts {; Diagnostic temperature sensing, e.g. for malignant or inflamed tissue} (clinical contact thermometers G01K13/20) - A61B 5/0507: using microwaves or terahertz waves - A61B 5/0537: Measuring body composition by impedance, e.g. tissue hydration or fat content - A61B 5/07: Endoradiosondes - A61B 5/14517: {for sweat} - A61B 5/14546: {for measuring analytes not otherwise provided for, e.g. ions, cytochromes} - A61B 5/6801: {specially adapted to be attached to or worn on the body surface} - A61B 2560/0214: of power generation or supply - A61B 2560/0223: of calibration, e.g. protocols for calibrating sensors - A61B 2560/0252: using ambient temperature - A61B 2562/164: the sensor is mounted in or on a conformable substrate or carrier - A61B: DIAGNOSIS; SURGERY; IDENTIFICATION (usefulness limited to only animals A61D) ## Abstract System for monitoring the hydration status of a living being by exploiting the modulation of backscattered RF electromagnetic waves from a wearable patched placed on the skin, said system comprising: a RF-tag adapted to be directly or indirectly fixed to the skin and containing at least one passive integrated circuit coupled to an antenna; an electromagnetic RF power source for supplying different signal frequencies to said RF-tag; a reader adapted to receive and to process the backscattered electromagnetic waves generated by said electromagnetic power source. ## Claims ### Claim 1 A wearable system for topically monitoring a physiological parameter reflecting a hydration status of a body of a living being, the system comprising: a RF-tag adapted to be directly or indirectly fixed to the skin of the living being and including a passive integrated circuit coupled to an antenna; an electromagnetic RF power source for supplying an incident wave having different signal frequencies to the RF-tag; a RF reader adapted to receive and to process backscattered electromagnetic waves that are backscattered by the RF-tag based on the incident wave generated by the electromagnetic RF power source to measure a variable impedance of the skin, and a data processor for determining a hydration level of the body of the living being based on measured variable impedance to determine whether the body of the living being is dehydrated. ### Claim 2 (depends on 1) The system according to claim 1 further comprising: a sensor for measuring the environment temperature; and a sensor for measuring at least one of the skin and the core-body temperature to provide for at least one of calibrated measurements taking into account a temperature influence on impedance characteristics, and independent monitoring of skin and/or core-body temperature. ### Claim 3 (depends on 1) The system according to claim 1, comprising a flexible substrate connected to the RF-tag adapted to be fixed to the skin. ### Claim 4 (depends on 1) The system according to claim 1 wherein the power source and the reader are included in a same element. ### Claim 5 A method for monitoring a hydration status of a body of a living being with a wearable system, the wearable system including a RF-tag having a passive integrated circuit coupled to an antenna, an electromagnetic RF power source, and a RF reader adapted to receive and to process backscattered electromagnetic waves backscattered by the RF-tag, the method comprising the following steps: directly or indirectly fixing the RF-tag to a skin of the living being; generating towards the RF-tag an incident wave having different signal frequencies with the RF power source to cause the backscattered electromagnetic waves from the RF-tag; collecting and processing the backscattered electromagnetic waves by the RF reader generated by the power source to determine a variable impedance of the skin, and determining a hydration level of the body to determine whether the body of the living being is dehydrated by processing the measured variable impedance. ### Claim 6 (depends on 5) The method according to claim 5 further comprising the step of: determining ions, bio-markers and other molecules, in at least one of the skin, and the sweat of the living being based on the backscattered electromagnetic waves. ### Claim 7 (depends on 1) The system according to claim 1, wherein the passive integrated circuit of the RF-tag is configured to be powered by energy coming from the incident wave supplied by the electromagnetic RF power source. ### Claim 8 (depends on 1) The system according to claim 1, wherein the RF-tag is configured to modulate wave characteristics of the backscattered electromagnetic waves based on an impedance characteristic of the antenna and a biological tissue at the skin. ### Claim 9 (depends on 1) The system according to claim 1, wherein the passive integrated circuit of the RF-tag is configured to send the backscattered electromagnetic waves to the RF reader via the antenna. ### Claim 10 (depends on 1) The system according to claim 1, wherein the backscattered electromagnetic waves include hydration information of the skin. ### Claim 11 (depends on 5) The method according to claim 5, further comprising the step of: powering the passive integrated circuit of the RF-tag by energy coming from the incident wave generated by the electromagnetic RF power source. ### Claim 12 (depends on 5) The method according to claim 5, wherein in the step of generating, the RF-tag modulates wave characteristics of the backscattered electromagnetic waves based on an impedance characteristic of the antenna and a biological tissue at the skin. ### Claim 13 (depends on 5) The method according to claim 5, wherein in the step of generating, the passive integrated circuit of the RF-tag sends the backscattered electromagnetic waves to the RF reader via the antenna. ### Claim 14 (depends on 5) The method according to claim 5, wherein the backscattered electromagnetic waves include hydration information of the skin. ### Claim 15 (depends on 1) The system according to claim 1, wherein the hydration level of the body is determined based on a variation of a phase velocity and a wavelength of the backscattered electromagnetic waves. ### Claim 16 (depends on 5) The method according to claim 5, wherein the hydration level of the body is determined based on a variation of a phase velocity and a wavelength of the backscattered electromagnetic waves. ### Claim 17 (depends on 1) The system according to claim 1, wherein the different signal frequencies are used to probe at different depths of the skin tissue to determine the hydration level. ### Claim 18 (depends on 5) The method according to claim 5, wherein the different signal frequencies are used to probe at different depths of the skin tissue to determine the hydration level. ### Claim 19 (depends on 1) The system according to claim 1, wherein the hydration level of the body is determined based on an amplitude and a phase of the backscattered electromagnetic waves. ### Claim 20 (depends on 5) The method according to claim 5, wherein the hydration level of the body is determined based on an amplitude and a phase of the backscattered electromagnetic waves. ### Claim 21 (depends on 1) The system according to claim 1, wherein the determination whether the body of the living being is dehydrated includes a determination whether hypernatremia and hypovolemia of the body is present. ### Claim 22 (depends on 5) The method according to claim 5, wherein the step of determining the hydration level includes a determination whether hypernatremia and hypovolemia of the body is present.