Cuffless PPG Blood Pressure Estimation Using Waveform Area Features
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Solution Overview
Problem
Existing methods for estimating blood pressure, such as those using pressure cuffs or photoelectric capacitive pulse waves, are limited in their accuracy and mobility, particularly for continuous monitoring outside clinical settings.
Innovation Solution
A cuffless method that utilizes a sensor to measure bio-signals, specifically a photoplethysmogram (PPG) signal, to estimate blood pressure by analyzing areas under distinct time intervals of the waveform, employing a processor to calculate systolic and diastolic blood pressure based on extracted features.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a pressure cuff is used to measure blood pressure, then measurement accuracy is improved, but mobility and ease of operation deteriorate
Solution Approach 1:
The patent replaces the mechanical pressure cuff system with an optical sensing system. A photoplethysmogram (PPG) sensor detects blood volume changes in the tissue, and a processor analyzes the waveform characteristics (including area under the curve calculations) to estimate blood pressure without requiring mechanical cuff inflation and deflation.
Solution Approach 2:
The patent introduces light as an intermediary to detect blood pressure indirectly. Instead of directly measuring pressure with a cuff, the system uses light absorption changes in blood vessels (photoplethysmography) to obtain waveform data, which then serves as an intermediary to calculate blood pressure parameters through area under the curve analysis.
2Reliability
If specialized medical personnel are involved in blood pressure monitoring, then measurement reliability is improved, but loss of time and productivity deteriorate
Solution Approach 1:
The system enables automatic blood pressure estimation without requiring skilled operators. The PPG sensor continuously captures waveform data, and the integrated processor automatically performs area under the curve calculations and blood pressure estimation, allowing the system to serve itself and eliminating dependence on medical personnel for routine monitoring.
Solution Approach 2:
The patent implements continuous blood pressure monitoring through the PPG sensor that continuously captures pulse waveforms. The processor continuously analyzes the waveforms and calculates area under the curve metrics in real-time, providing uninterrupted blood pressure estimation without the intermittent manual measurements required by traditional methods.
3Measurement precision
If traditional blood pressure measurement methods are used, then measurement precision is improved, but device complexity and ease of manufacture worsen
Solution Approach 1:
The patent extracts the essential measurement function from the complex mechanical cuff system and isolates it into a simple optical sensor. By taking out only the necessary sensing function (detecting blood volume changes via light) and eliminating the mechanical inflation/deflation mechanism, the system achieves comparable measurement precision with significantly reduced structural complexity.
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
Enables accurate estimation of systolic and diastolic blood pressure without a cuff, facilitating continuous monitoring and reducing the need for specialized medical personnel.
Implementation Method 1
a photoplethysmogram (PPG) signal, an electromyography (EMG) signal, and the like, and various bio-signal sensors are being developed to measure these signals in daily life. Particularly, a PPG sensor may estimate blood pressure of a human body by analyzing a pulse waveform
Data Source
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Figure 1B
Figure 2A
AI summary
A blood pressure estimating apparatus is provided. The blood pressure estimating apparatus may include: a sensor configured to measure a bio-signal waveform; and a processor configured to obtain a first feature based on a first area under the bio-signal waveform in a first time interval, obtain a second feature based on a second area under the bio-signal waveform in a second time interval which is different from the first time interval, and estimate blood pressure based on the first feature and the second feature.