Sphygmomanometer Pulse Wave Amplitude Correction

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Solution Overview

Problem

Miniaturization and cost reduction of blood pressure measurement devices lead to non-constant cuff compression pace, resulting in errors in pulse wave amplitude calculation and decreased measurement accuracy.

Innovation Solution

An oscillometric type sphygmomanometer with a central control unit that includes a cuff pressure detection section, pulse rate calculation section, pulse wave amplitude calculation section, and pulse wave amplitude correction section, which corrects pulse wave amplitude based on the change in cuff pressure pace and pulse rate using a predetermined method, ensuring accurate blood pressure determination.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If miniaturization and cost reduction of pump are pursued, then device size and cost decrease, but cuff compression pace becomes non-constant and measurement accuracy decreases

Engineering Contradiction:

Improvecost reductionVSAvoidmeasurement accuracy

Core Design Contradiction:

Ease of manufactureVSMeasurement precision

Solution Approach 1:

The patent applies feedback by continuously monitoring the actual cuff compression pace through pressure sensors and comparing it against the target pace. When deviations are detected, the control unit adjusts pump operation to correct the compression pace, ensuring measurement accuracy is maintained despite using miniaturized, less precise pumps

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The patent changes operational parameters by dynamically adjusting pump flow rate and cuff inflation/deflation speed based on real-time pressure measurements. The system adapts compression pace parameters to compensate for variations introduced by miniaturized pump components

Inventive Principle:

Principle #35Parameter changes

2Ease of manufacture

If miniaturization and cost reduction of pump are pursued, then device size and cost decrease, but cuff compression pace becomes non-constant and measurement accuracy decreases

Engineering Contradiction:

Improvecost reductionVSAvoiddevice complexity

Core Design Contradiction:

Ease of manufactureVSDevice complexity

Solution Approach 1:

The patent introduces feedback mechanisms with pressure sensors and control algorithms that continuously monitor and adjust cuff compression. This adds control complexity but compensates for the simpler, cheaper pump components, achieving a balance between device complexity and manufacturing cost

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The patent replaces complex mechanical flow control mechanisms with electronic control systems. Instead of using mechanically precise pumps, the system uses microprocessors and sensors to achieve precise cuff compression control, reducing mechanical complexity and manufacturing cost

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Device complexity

If cuff compression pace is not constant, then device simplicity is maintained, but pulse wave amplitude calculation generates errors

Engineering Contradiction:

Improvedevice simplicityVSAvoidamplitude accuracy

Core Design Contradiction:

Device complexityVSMeasurement precision

Solution Approach 1:

The patent uses feedback from pressure sensors to continuously monitor cuff compression in real-time. The control unit adjusts pump operation based on actual compression pace deviations, maintaining constant compression despite simpler pump mechanisms

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The patent applies dynamic control by continuously adjusting cuff compression parameters during measurement. The system adapts compression pace moment-by-moment to maintain optimal conditions for pulse wave detection, transforming a static simple system into a dynamic controlled one

Inventive Principle:

Principle #15Dynamics

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

The solution improves the accuracy of blood pressure measurement by correcting amplitude errors caused by non-constant cuff compression pace, enhancing the precision of pulse wave detection and overall measurement accuracy.

Implementation Method 1

a pressure sensor for measuring a cuff pressure on the measurement location during inflation/deflation of the cuff

Methodology Applied

Scientific EffectPressure detection:

Implementation Method 2

a pump and valve for inflating/deflating the cuff

Methodology Applied

Scientific EffectFluid pressure: Pressure Increase

Data Source

PatentUS9271655B2Oscillometric type sphygmomanometer

Publication Date: 2016.03.01 OMRON HEALTHCARE CO LTD

AI summary

A sphygmomanometer includes a pulse wave detecting section, a pulse wave amplitude calculation section, a pace change calculation section, and a pulse wave amplitude correction section. The pulse wave detecting section detects pulse waves, and the pulse wave amplitude calculation section calculates an amplitude of a pulse wave. The pace change calculation section calculates the amount of change of the increasing/decreasing pace of the cuff pressure between pulse waves based on the difference between the increasing/decreasing pace of the cuff pressure during a period of the pulse wave and the increasing/decreasing pace of the cuff pressure during a period of a preceding pulse wave. The pulse wave amplitude correction section corrects the amplitude of the pulse wave based on the amount of change of the increasing/decreasing pace of the cuff pressure. A blood pressure value is determined based on the corrected amplitude of the pulse wave.