Inductive Pulse Wave Sensor for Non-Invasive Blood Pressure Monitoring
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Solution Overview
Problem
Existing non-invasive blood pressure measurement methods are prone to measurement artifacts due to varying conditions and patient compliance issues, and they often require external pressure cuffs or electrodes, which can be cumbersome and inaccurate.
Innovation Solution
A sensor using principles of magnetic induction to detect pulse waves through inductive coupling with the body, allowing for contactless and cuff-free measurement of blood pressure and vital signs by detecting changes in blood volume, geometry, and conductivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional non-invasive blood pressure measurement methods (sphygmomanometers, oscillometric techniques, tonometry) are used, then blood pressure can be measured non-invasively, but external pressure cuffs must be applied to the subject's body which causes measurement artifacts due to varying conditions and patient non-compliance
Solution Approach 1:
The patent extracts and eliminates the external pressure cuff from the measurement system. Instead of applying a cuff to the subject's body, the invention uses a sensor that detects pulse waves through the skin surface, removing the source of measurement artifacts caused by cuff position, size, and pressure variations.
Solution Approach 2:
The patent replaces the mechanical cuff-based measurement system with an optical/electrical sensor system. The sensor detects changes in light absorption or electrical properties of the skin and underlying tissues during pulse wave propagation, substituting mechanical pressure application with non-contact or minimal-contact detection methods.
2Measurement precision
If ECG and PPG combined methods are used to measure PTT, then pulse transit time can be determined, but electrodes must be glued to the skin which reduces ease of use and may cause skin irritation
Solution Approach 1:
The patent removes the requirement for skin-adhered electrodes by using sensors that detect pulse waves through the skin surface. The measurement can be performed with the sensor placed on or near the skin without requiring adhesive application, eliminating skin irritation and simplifying the measurement process.
Solution Approach 2:
The patent uses the skin and underlying tissues as an intermediary medium through which the sensor can detect pulse waves without direct contact or adhesion. The sensor detects changes in optical or electrical properties of these intermediate layers, allowing measurement without electrodes glued to the skin.
3Measurement precision
If PPG sensors are placed at body points under which arteries are close to the skin, then pulse waves can be detected, but the measurement location is limited and may reduce measurement accuracy for certain subjects
Solution Approach 1:
The patent creates a universal sensor that can detect pulse waves at multiple body locations regardless of artery proximity to the skin surface. The sensor is designed to penetrate or detect through various tissue depths, making it adaptable to different body sites and subject anatomies without requiring precise placement over specific arterial points.
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, non-invasive, and continuous monitoring of blood pressure and other vital signs without the need for external pressure cuffs or skin contact, improving measurement accuracy and user convenience.
Implementation Method 1
the sensor comprises a number of electrical coils for generating an inductive coupling to the subject's body in a way that the properties of said inductive coupling change if a pulse passes a screened volume underneath the sensing position
Data Source
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AI summary
In order to provide an easy-to-use technique for measuring blood pressure and/or other vital signs of a subject, a sensor for detecting the passing of a pulse wave from a subject's arterial system is suggested, the sensor being adapted to be located at a sensing position on the exterior of the subject's body, characterized in that the sensor comprises a number of electrical coils for generating an inductive coupling to the subject's body in a way that the properties of said inductive coupling change if a pulse wave passes a screened volume underneath the sensing position, and a circuit connected to the number of electrical coils, said circuit being adapted to detect said property changes of the inductive coupling.