Central Systolic Blood Pressure Estimation via Transfer Function
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Solution Overview
Problem
Existing blood pressure monitoring devices primarily measure peripheral systolic blood pressure, which exceeds central systolic blood pressure, making them less accurate for indicating heart load and predicting cardiovascular events, and current non-invasive methods like SphygmoCor are expensive, require trained personnel, and introduce systematic errors.
Innovation Solution
A non-invasive blood pressure determining device measures peripheral blood pressure waveforms and measurements within the cardiac cycle, applying a transfer function to estimate central systolic blood pressure using a conventional oscillometric blood pressure monitor, eliminating the need for multiple devices and reducing systematic errors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a conventional non-invasive blood pressure determining device is used to measure peripheral blood pressure, then the device is inexpensive and easy to operate, but the measurement accuracy for central systolic blood pressure is reduced due to pressure amplification in peripheral arteries
Solution Approach 1:
The patent introduces a transfer function as an intermediary mathematical model that transforms peripheral blood pressure waveform measurements into estimates of central blood pressure waveform. This transfer function acts as a mediator that bridges the gap between easily obtainable peripheral measurements and the desired central pressure values, resolving the contradiction by enabling accurate central pressure estimation through mathematical transformation rather than direct measurement
Solution Approach 2:
The patent replaces the need for complex mechanical measurement systems (like catheter-based aortic pressure measurement or specialized devices such as SphygmoCor) with a computational approach. By substituting the mechanical measurement system with a mathematical transfer function applied to standard oscillometric measurements, the system achieves central pressure accuracy without requiring expensive or complex hardware
2Measurement precision
If the SphygmoCor device is used to estimate central systolic blood pressure, then measurement accuracy is improved, but the device complexity and cost increase significantly
Solution Approach 1:
The patent makes the standard oscillometric blood pressure determining device multi-functional by enabling it to perform both conventional peripheral blood pressure measurement and central blood pressure estimation using the same hardware. The device applies the transfer function to the existing peripheral waveform data, allowing one simple device to serve multiple purposes without requiring separate specialized equipment
Solution Approach 2:
The patent creates a mathematical copy or representation of the central blood pressure waveform from the peripheral waveform measurements. Instead of physically measuring central pressure with complex equipment, the system generates a computational copy of the central pressure signal through the transfer function, achieving the same informational value with simpler means
3Measurement precision
If the SphygmoCor device is used to estimate central systolic blood pressure, then measurement accuracy is improved, but the time required for measurement increases
Solution Approach 1:
The patent performs preliminary computational processing by applying the transfer function to the peripheral waveform during the same measurement cycle. The system prepares and processes the waveform data in real-time as part of the standard measurement procedure, so that central pressure estimation is obtained simultaneously with peripheral pressure measurement rather than requiring additional separate measurement steps
4Ease of operation
If calibration from brachial artery blood pressure is performed, then the measurement process is simplified, but systematic error is introduced due to pressure differences between brachial and radial arteries
Solution Approach 1:
The patent extracts and removes the source of systematic error by eliminating the need for separate brachial artery calibration. The transfer function is applied directly to the radial waveform without requiring calibration against brachial pressure measurements, thereby taking out the calibration step that introduces error while maintaining the simplicity of the measurement process
Data Source
AI summary
The application relates to an apparatus and a method for estimating a central systolic blood pressure (cSBP) of a subject, in which a peripheral blood pressure waveform of the subject's pulse and at least two peripheral blood pressure measurements within the cardiac cycle of the subject are determined and the peripheral blood pressure waveform is manipulated with a transfer function to provide an estimate of the central blood pressure waveform of the subject's pulse. The at least two peripheral blood pressure measurements within the cardiac cycle of the subject and the peripheral blood pressure waveform of the subject's pulse are determined at substantially the same point on a peripheral artery of the subject. The estimate of the central blood pressure waveform of the subject's pulse provides an estimate of the central systolic blood pressure of the subject.