Wearable Blood Pressure Sensing with PPG and Contact Pressure
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Solution Overview
Problem
Existing blood pressure measurement methods on wearable devices suffer from inaccuracies due to factors such as cuff inflation limitations, pulse transmission time inconsistencies, and PPG signal quality issues, leading to unreliable blood pressure readings.
Innovation Solution
A blood pressure measurement method for wearable devices using three pressure transducers and a photoplethysmography module to collect pressure and PPG signals, employing neural networks to determine systolic and diastolic blood pressures based on waveform features and pressure values, with guidance for uniform pressure application and stability checks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If existing blood pressure measurement methods (cuff inflation, PTT, PPG waveform) are used on wearable devices, then the device can provide blood pressure monitoring function, but the measurement accuracy is poor
Solution Approach 1:
The patent combines multiple measurement approaches (PPG waveform analysis, pulse transmission time measurement, and pressure sensor data) into a unified blood pressure measurement system. The processor integrates signals from the PPG module, pressure transducers, and other sensors to calculate blood pressure values, thereby improving measurement accuracy and reliability compared to using any single method alone.
Solution Approach 2:
The patent introduces pressure transducers as intermediary components between the wearable device and the user's body. These pressure sensors measure the pressure applied by the user and use it as a reference to calibrate and improve the accuracy of blood pressure measurements derived from PPG and PTT methods.
2Measurement precision
If pressure is applied to improve PPG signal quality for blood pressure measurement, then measurement accuracy may improve, but pressure distribution uniformity becomes difficult to control
Solution Approach 1:
The patent divides the pressure measurement function into multiple independent pressure transducers distributed at different locations on the wearable device. By measuring pressure at multiple points simultaneously, the system can assess pressure distribution uniformity and provide guidance to achieve optimal pressure application for improved PPG signal quality.
Solution Approach 2:
The patent implements a feedback mechanism where the processor analyzes pressure values from multiple transducers and provides real-time feedback to the user about pressure application. This guidance helps users adjust their pressure application to achieve uniform distribution, thereby improving PPG signal quality without compromising pressure uniformity.
3Reliability
If multiple pressure transducers and PPG modules are deployed to improve measurement accuracy, then blood pressure measurement reliability improves, but device complexity increases
Solution Approach 1:
The patent designs the wearable device with components that serve multiple functions. The PPG module is used not only for blood pressure measurement but also for heart rate monitoring and other physiological measurements. The pressure transducers serve both as reference pressure sensors for calibration and as direct measurement sensors, reducing the need for separate dedicated components.
Solution Approach 2:
The patent merges multiple measurement functions into a single integrated system. The processor simultaneously processes PPG signals, pressure sensor data, and other sensor inputs to perform blood pressure measurement, heart rate monitoring, and other health tracking functions, thereby reducing overall device complexity while maintaining high measurement reliability.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Improves blood pressure measurement accuracy by considering pressure factors and PPG signal waveform features, ensuring accurate systolic and diastolic readings while allowing for autonomous and periodic measurements.
Implementation Method 1
a photoplethysmography PPG module... obtaining a PPG signal collected by the PPG module
Implementation Method 2
obtaining a pressure value collected by the PTs... three pressure transducers (pressure transducer, PT)
Data Source
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AI summary
This application provides a blood pressure measurement method for a wearable device and a wearable device, so as to improve measurement accuracy of a blood pressure value. The wearable device includes a pressure transducer PT and a photoplethysmography PPG module. The PT and the PPG module are deployed at a target position of the wearable device. The target position includes a position for contacting a wearer when the wearable device is in a worn state. The method includes: obtaining a pressure value collected by the PT; obtaining a PPG signal collected by the PPG module; and determining a blood pressure value of the wearer based on the pressure value and the PPG signal. If the wearer wears the wearable device on a wrist, a PPG signal of the wrist of the wearer may be collected, and a pressure value between the wearable device and the wrist may be collected according to this application. Adding pressure value information based on the PPG signal may improve measurement accuracy of the blood pressure value.