# US 11,298,086 B2 · Apparatus and method for estimating blood pressure > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 11,298,086 B2 - Document ID: US11298086B2 - Status: Granted - Kind: B2 - Application number: 16/409,128 - Filed: 2019-05-10 - Published: 2020-04-09 - Granted: 2022-04-12 - Earliest claimed: 2018-10-05 - Assignees: Samsung Electronics Co., Ltd. - Applicants: Samsung Electronics Co., Ltd. - Inventors: Ui Kun Kwon; Chang Soon Park - Web page: https://patentgrep.com/patent/US11298086B2 ## CPC - A61B 5/02108: {from analysis of pulse wave characteristics} - A61B 5/7278: {Artificial waveform generation or derivation, e.g. synthesizing signals from measured signals} - A61B 5/02007: {Evaluating blood vessel condition, e.g. elasticity, compliance} - A61B 5/02116: {of pulse wave amplitude (A61B5/02225 takes precedence)} - A61B 5/029: Measuring blood output from the heart, e.g. minute volume - A61B 5/0004: {characterised by the type of physiological signal transmitted} - A61B 5/024: Measuring pulse rate or heart rate - A61B 5/681: {Wristwatch-type devices} - A61B 2560/0223: of calibration, e.g. protocols for calibrating sensors - A61B: DIAGNOSIS; SURGERY; IDENTIFICATION (usefulness limited to only animals A61D) ## Abstract An apparatus for estimating blood pressure is provided. The apparatus for estimating blood pressure may include: a bio-signal measurer configured to measure a bio-signal from a user; and a processor configured to extract one or more feature values from the bio-signal, to adjust a combination coefficient for combining the one or more feature values based on a reference value associated with vascular compliance, and to estimate blood pressure based on the adjusted combination coefficient, and the one or more feature values extracted from the bio-signal. ## Claims ### Claim 1 An apparatus for estimating blood pressure, the apparatus comprising: a photoplethysmogram (PPG) sensor configured to measure a bio-signal from a user; and a processor configured to: extract, from the bio-signal, one or more feature values comprising a first feature value that shows an increasing or decreasing trend in proportion to an actual cardiac output, and a second feature value that shows an increasing or decreasing trend in proportion to an actual total peripheral resistance, obtain a first variation in the first feature value compared to a first reference feature value, a second variation in the second feature value compared to a second reference feature value, and a third variation based on the first variation and the second variation, and estimate a blood pressure based on the first variation, the second variation, and the third variation. ### Claim 2 (depends on 1) The apparatus of claim 1, wherein the first reference feature value and the second reference feature value are obtained at a calibration time of the bio-signal or a time at which the user is in a stable state. ### Claim 3 (depends on 1) The apparatus of claim 1, wherein the processor is further configured to: obtain, as a reference value associated with vascular compliance, a maximum amplitude value of a reference bio-signal that is measured from the user at a reference time; obtain combination coefficients to be applied to the first variation, the second variation, and the third variation, respectively, based on the reference value associated with vascular compliance; and estimate the blood pressure by combining the first variation, the second variation, and the third variation to which the combination coefficients are applied. ### Claim 4 (depends on 1) The apparatus of claim 1, wherein the processor is further configured to: obtain a reference bio-signal including a first pulse waveform component and a second pulse waveform component, from the user at a reference time; obtain, as a reference value associated with vascular compliance, at least one of a ratio between a first amplitude value of the first pulse waveform component and a second amplitude value of the second pulse waveform component of the reference bio-signal, and a ratio between the first amplitude value and a maximum amplitude value of the reference bio-signal; obtain combination coefficients to be applied to the first variation, the second variation, and the third variation, respectively, based on the reference value associated with vascular compliance; and estimate the blood pressure by combining the first variation, the second variation, and the third variation to which the combination coefficients are applied. ### Claim 5 (depends on 1) The apparatus of claim 1, wherein the processor is further configured to: obtain a reference value associated with vascular compliance that comprises a vascular compliance index including an Augmentation Index; obtain combination coefficients to be applied to the first variation, the second variation, and the third variation, respectively, based on the reference value associated with vascular compliance; and estimate the blood pressure by combining the first variation, the second variation, and the third variation to which the combination coefficients are applied. ### Claim 6 (depends on 5) The apparatus of claim 5, wherein the processor is further configured to receive the vascular compliance index from an external device which measures the vascular compliance of the user. ### Claim 7 (depends on 5) The apparatus of claim 5, wherein the processor is further configured to obtain the Augmentation Index by analyzing a waveform of the reference bio-signal that is measured from the user at reference time. ### Claim 8 (depends on 1) The apparatus of claim 1, wherein the processor is further configured to: obtain combination coefficients to be applied to the first variation, the second variation, and the third variation, respectively, based on a reference value associated with vascular compliance; and estimate the blood pressure by combining the first variation, the second variation, and the third variation to which the combination coefficients are applied. ### Claim 9 (depends on 8) The apparatus of claim 8, wherein the processor is further configured to obtain an adjustment value for adjusting the combination coefficients by inputting a statistical value of a plurality of reference values obtained from a plurality of other users, into a pre-defined adjustment value estimation equation. ### Claim 10 (depends on 1) The apparatus of claim 1, wherein the processor is further configured to obtain at least one information of heart rate information, an area under a waveform of the bio-signal, time and amplitude values of a maximum point of the bio-signal, time and amplitude values of a minimum point of the bio-signal, and amplitude and time values of pulse waveform components included in the bio-signal, and extract the one or more feature values based on the at least one information. ### Claim 11 (depends on 1) The apparatus of claim 1, wherein the processor is further configured to adjust a plurality of combination coefficients corresponding to the first variation, the second variation, and the third variation, and combine the first variation, the second variation, and the third variation by multiplying the first variation, the second variation, and the third variations by the adjusted plurality of combination coefficients, respectively. ### Claim 12 (depends on 11) The apparatus of claim 11, wherein the processor is further configured to estimate the blood pressure by applying a scaling factor to a resulting value of the combining the first variation, the second variation, and the third variation. ### Claim 13 A method of estimating blood pressure, the method comprising: measuring a bio-signal from a user; extracting, from the bio-signal, one or more feature values comprising a first feature value that shows an increasing or decreasing trend in proportion to an actual cardiac output, and a second feature value that shows an increasing or decreasing trend in proportion to an actual total peripheral resistance; obtain a first variation in the first feature value compared to a first reference feature value, a second variation in the second feature value compared to a second reference feature value, and a third variation based on the first variation and the second variation; and estimating a blood pressure based on the first variation, the second variation, and the third variation, and the one or more feature values extracted from the bio signal. ### Claim 14 (depends on 13) The method of claim 13, further comprising: obtaining, as a reference value associated with vascular compliance, a maximum amplitude value of a reference bio-signal that is measured from the user at a reference time; obtaining combination coefficients to be applied to the first variation, the second variation, and the third variation, respectively, based on the reference value associated with vascular compliance; and estimating the blood pressure by combining the first variation, the second variation, and the third variation to which the combination coefficients are applied. ### Claim 15 (depends on 13) The method of claim 13, further comprising: obtaining a reference bio-signal including a first pulse waveform component and a second pulse waveform component, from the user at a reference time; obtaining, as a reference value associated with vascular compliance, at least one of a ratio between a first amplitude value of the first pulse waveform component and a second amplitude value of the second pulse waveform component of the reference bio-signal, and a ratio between the first amplitude value and a maximum amplitude value of the reference bio-signal; obtaining combination coefficients to be applied to the first variation, the second variation, and the third variation, respectively, based on the reference value associated with vascular compliance; and estimating the blood pressure by combining the first variation, the second variation, and the third variation to which the combination coefficients are applied. ### Claim 16 (depends on 13) The method of claim 13, further comprising obtaining combination coefficients to be applied to the first variation, the second variation, and the third variation, respectively, based on a reference value associated with vascular compliance; and estimating the blood pressure by combining the first variation, the second variation, and the third variation to which the combination coefficients are applied. ### Claim 17 (depends on 16) The method of claim 16, further comprising: obtaining an adjustment value for wherein the adjusting the combination coefficients by inputting a statistical value of a plurality of values obtained from a plurality of other users, into a pre-defined adjustment value estimation equation.