Pulse Wave Approximation via Weighted Signal Transfer
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Solution Overview
Problem
Current non-invasive blood pressure measurement methods, such as the oscillometric method, cannot reliably determine the shape of a patient's pulse wave, which is crucial for health assessment, and existing methods like the volume-clamp method are prone to errors and interference due to pressure reflections when measuring at locations remote from the heart.
Innovation Solution
A method involving non-invasive measurement of pulse signals, weighting these signals using a differential pressure function, and iteratively adding them to approximate the central arterial pulse wave without the need for continuous pressure cuff adjustments, allowing for accurate pulse wave approximation near the heart.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If the oscillometric non-invasive blood pressure measurement method is used, then the measurement is less dangerous and more convenient, but the shape of the pulse wave cannot be reliably determined
Solution Approach 1:
The patent uses a transfer function as an intermediary to translate peripheral pulse wave measurements into central pulse wave characteristics. The transfer function acts as a mathematical mediator that converts the oscillometric signal from the cuff into an approximation of the central arterial pulse wave shape, enabling reliable determination of pulse wave morphology without invasive catheterization.
Solution Approach 2:
The patent replaces the mechanical invasive catheter-based measurement system with a mathematical modeling approach. Instead of physically inserting a catheter into blood vessels, the system uses computational algorithms (transfer functions) to derive central pulse wave characteristics from non-invasive oscillometric measurements, eliminating the need for mechanical intrusion while preserving measurement accuracy.
2Duration of action of stationary object
If the volume-clamp method is used to measure pulse waves, then the measurement can be performed continuously, but errors and interference occur due to pressure reflections when measuring at locations remote from the heart
Solution Approach 1:
The transfer function serves as a mathematical intermediary that corrects for the distorting effects of pressure reflections and wave propagation delays. By applying this transfer function to the peripheral oscillometric signals, the system reconstructs the central pulse wave shape, effectively eliminating the measurement errors introduced by remote measurement locations while maintaining continuous monitoring capability.
Solution Approach 2:
The patent transforms the measurement parameters by applying a transfer function that adjusts the peripheral pulse wave signal into an approximation of central pulse wave characteristics. This parameter transformation accounts for the differences in wave propagation between peripheral and central arteries, converting the measured oscillations into accurate central pulse wave representations without requiring changes in measurement location.
3Measurement precision
If the pressure in the pressure cuff is continuously increased over a time period corresponding to multiple heart beats, then the systolic and diastolic blood pressure values can be determined, but the pulse wave shape becomes distorted and varies significantly between heart beats
Solution Approach 1:
The transfer function acts as a stabilizing intermediary that normalizes the varying pulse signals obtained during cuff inflation. By applying this mathematical transformation to each individual pulse signal, the system compensates for the distortions caused by changing cuff pressure, producing a consistent and reliable approximation of the central pulse wave shape that remains stable throughout the measurement process.
Solution Approach 2:
The patent applies the transfer function in advance to each measured pulse signal before aggregation. This preliminary mathematical processing pre-corrects the signals for the expected distortions caused by cuff pressure changes, ensuring that when the signals are combined to determine blood pressure values, the pulse wave shape information is already stabilized and consistent across all heart beats.
Data Source
AI summary
In an approach to non-invasive blood pressure measurements, a blood pressure measurement system receives a pulse curve signal representing a sequence of pulse curves of a subject from a pressure cuff. The blood pressure measurement system applies a weighting function that applies one or more weights to a pulse curve of the sequence of pulse curves to obtain a weighted pulse curve and the one or more non-constant clamp pressure signals are a weighting function input parameter. The blood pressure measurement system sums at least the weighted pulse curve and a second weighted pulse curve, which approximates a shape and an amplitude of a pulse wave of the subject. The blood pressure measurement system determines a health status of the subject based on the pulse wave and generates a graphical representation of the pulse wave of the subject and the health status of the subject.