Piezoelectric Wearable Sensor for Continuous Blood Pressure Waveform Monitoring
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Solution Overview
Problem
Current cardiovascular monitoring systems are invasive, cumbersome, and lack the capability for continuous, non-invasive, real-time measurement of blood pressure waveforms and vascular tone, limiting their use in portable and wearable applications, especially in dynamic physiological states.
Innovation Solution
A wearable sensor assembly with a flexible band and piezoelectric sensors that measure vascular wall motion and blood flow, combined with photoplethysmograph-derived data, processed to extract indicators of vascular health, enabling continuous monitoring and potential therapeutic interventions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If invasive monitoring techniques are used to obtain true blood pressure waveform data, then measurement precision is improved, but device complexity and ease of operation deteriorate
Solution Approach 1:
The patent replaces the mechanical/invasive arterial catheter system with a piezoelectric sensor system that detects vascular wall motion through acoustic/electrical signals. The piezoelectric material converts mechanical stress from vascular wall motion directly into electrical signals, eliminating the need for invasive mechanical insertion while maintaining measurement capability
Solution Approach 2:
The patent introduces piezoelectric material as an intermediary between the vascular wall and the measurement system. The piezoelectric sensor detects vibrations and motions of the vascular wall through acoustic coupling, serving as a mediator that translates biological mechanical motion into measurable electrical signals without direct invasive contact
2Ease of operation
If non-invasive monitoring systems are used to improve ease of operation, then portability is improved, but measurement precision deteriorates due to reduced waveform data
Solution Approach 1:
The patent employs dynamic signal processing techniques including wavelet transforms and empirical mode decomposition to extract meaningful waveform features from the piezoelectric sensor signals. These dynamic processing methods enable reconstruction of accurate blood pressure waveforms from the raw acoustic/electrical signals, maintaining measurement precision while preserving portability
Solution Approach 2:
The patent transforms the raw piezoelectric sensor signals through multiple parameter changes including frequency domain transformation, time-frequency analysis, and derivation of various hemodynamic parameters (pulse pressure, stroke volume, vascular tone). These parameter transformations convert simple acoustic signals into comprehensive cardiovascular measurements
3Measurement precision
If mechanical cuff inflation is used to obtain blood pressure data, then measurement capability is improved, but device complexity and ease of operation worsen due to obstruction of normal activities
Solution Approach 1:
The patent extracts the essential measurement function from the complex mechanical cuff system. By using piezoelectric sensors to detect vascular wall motion directly, the system removes the inflatable cuff, pump, and complex mechanical components while retaining the core capability of blood pressure measurement through a simplified wearable form factor
4Productivity
If continuous monitoring is implemented to improve productivity, then real-time data availability is improved, but use of energy deteriorates
Solution Approach 1:
The patent implements periodic sampling of the piezoelectric sensor signals at optimized intervals rather than continuous high-rate acquisition. The signal processing is performed in discrete time windows, allowing the system to maintain continuous monitoring capability while reducing average power consumption through duty-cycled operation and event-triggered processing
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, real-time monitoring of cardiovascular parameters, providing valuable clinical decision-making tools and facilitating more effective management of disease states through continuous, non-invasive, and portable means.
Implementation Method 1
a piezoelectric sensor for measuring raw signal data, in real time, of vascular wall motion and blood flow dependent measurements, wherein the piezoelectric sensor comprises a piezoelectric electrode structure in the sensing layer for measuring the raw signal data in response to physical movement of the sensor region
Implementation Method 2
a secondary sensor for collecting and extracting photoplethysmograph derived blood flow data
Data Source
AI summary
The invention is a passive, wearable sensor that uses a thin piezoelectric material to produce a time history of blood pressure of the patient, with signal processing algorithms to extract physiological information. The sensor consists of a piezoelectric transducer set in a polymer laminate that can be applied to the finger or wrist of the patient. During use, a combination of compressive and bending deformation in the piezoelectric layer in response to blood pressure in the finger or wrist as a voltage output. Using signal processing techniques, the raw signal is filtered and decomposed to obtain a information to form derivative signals such as blood pressure, pulse pressure, pulse pressure variability, heart rate, heart rate variability, and respiratory rate which can be very important pre-cursors in the monitoring of the patient's physiological conditions.