Wearable Cuff Inflation Speed Control for Blood Pressure Accuracy

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Solution Overview

Problem

Existing methods for controlling wearable cuffs during blood pressure measurement face challenges such as discomfort due to high cuff pressures and artifacts induced by changing inflation speeds, which can lead to inaccurate measurements.

Innovation Solution

The apparatus controls the inflation speed of a wearable cuff by initiating inflation at a first speed and changing it at a rate limited to a maximum value, dependent on the subject's pulse rate and pressure oscillation amplitude, to minimize artifacts and ensure accurate blood pressure measurement.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If the inflation speed is changed rapidly to reduce measurement time, then productivity is improved, but measurement precision deteriorates due to artifacts in the pressure signal

Engineering Contradiction:
Improvemeasurement timeVSAvoidblood pressure measurement accuracy
Core Design Contradiction:
ProductivityVSMeasurement precision

Solution Approach 1:

The patent dynamically adjusts the inflation speed parameter based on detected pulse rate and oscillation amplitude. By changing the inflation speed parameter adaptively rather than using a fixed speed, the system optimizes the balance between measurement time and signal quality, reducing artifacts while maintaining productivity

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The system uses feedback from detected pressure oscillations and pulse rate to continuously adjust the inflation speed. The feedback mechanism monitors the pressure signal quality and modifies the inflation parameters in real-time to minimize artifacts and ensure accurate blood pressure determination

Inventive Principle:
Principle #23Feedback

2Reliability

If the cuff is inflated to high pressure levels to ensure adequate occlusion, then measurement reliability is improved, but object-affected harmful factors worsen due to subject discomfort and venous pooling

Engineering Contradiction:
Improveblood pressure measurement reliabilityVSAvoidsubject discomfort
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent implements dynamic inflation where the cuff pressure is adjusted in real-time based on detected oscillation amplitudes and pulse rate. Rather than inflating to a fixed high pressure, the system dynamically adapts the pressure level to the minimum required for adequate occlusion, reducing subject discomfort while maintaining measurement reliability

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system performs preliminary detection of pulse rate and oscillation characteristics before final blood pressure determination. This preliminary action allows optimization of inflation parameters in advance, ensuring adequate occlusion is achieved with minimal necessary pressure, thereby reducing venous pooling and discomfort

Inventive Principle:
Principle #10Preliminary action

3Measurement precision

If the inflation speed is changed adaptively based on pulse rate, then measurement precision is improved, but device complexity increases due to additional control mechanisms

Engineering Contradiction:
Improveblood pressure measurement precisionVSAvoidcontrol system complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The system uses the subject's own physiological signals (pulse rate and oscillation amplitude) to automatically adjust inflation parameters. The measurement process itself provides the information needed for control, eliminating the need for external sensors or complex pre-programming, thus improving precision without excessive complexity

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The pressure oscillation detection serves multiple functions: it characterizes the pulse waveform, determines pulse rate, guides inflation speed adjustment, and eventually determines blood pressure. This multi-functionality reduces the need for separate control mechanisms, achieving improved precision with manageable device complexity

Inventive Principle:
Principle #6Universality (Multi-functionality)

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

This approach reduces discomfort and improves measurement accuracy by limiting the rate of inflation speed changes, thereby minimizing artifacts in the pressure signal and allowing for more precise blood pressure determination during the inflation stage.

Implementation Method 1

In the oscillometric method for blood pressure measurement, the systolic and diastolic blood pressure values are based on small volume oscillations or pressure oscillations that are induced in the cuff by each heart beat.

Methodology Applied
Scientific EffectOscillometric method:

Implementation Method 2

The amplitude of these volume or pressure oscillations depends on the difference between the cuff pressure and the actual arterial blood pressure.

Methodology Applied
Scientific EffectPressure oscillation:

Data Source

PatentEP3752052B1Controlling a wearable cuff
Publication Date: 2021.10.06 KONINKLIJKE PHILIPS NV
  • EP3752052B1 patent drawingFigure 1
  • EP3752052B1 patent drawingFigure 2
  • EP3752052B1 patent drawingFigure 3

AI summary

There is provided an apparatus (12) for controlling a wearable cuff (14) for use in measuring blood pressure, wherein the wearable cuff (14) is inflatable to pressurize a measurement site of a subject (18). The apparatus (12) is configured to initiate the inflation of the wearable cuff (14) at a first inflation speed and change the first inflation speed during inflation of the wearable cuff (14). The first inflation speed is changed at a rate that is limited to a maximum value.