Blood Pressure Cuff Control Target Value Dynamics
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Solution Overview
Problem
Conventional blood pressure measurement devices using the volume compensation method face inaccuracies due to the influence of body tissue deformation, limiting measurements to specific areas like the finger and resulting in underestimation of pulse pressure differences.
Innovation Solution
A blood pressure measurement device and method that dynamically adjusts the control target value based on body tissue deformation by detecting arterial volume changes and using a low-pass filter to interpolate diastolic and systolic blood pressure values, ensuring accurate cuff pressure control and blood pressure measurement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a fixed control target value is used for the entire range of control cuff pressures, then the device complexity is reduced, but the measurement precision deteriorates due to body tissue deformation influence
Solution Approach 1:
The control target value is changed from a fixed value to a dynamic value that varies according to the cuff pressure. The determination unit dynamically determines control target values at different cuff pressure points (diastolic and systolic blood pressure points) and the change unit interpolates between these points to provide appropriate control target values for different measurement conditions, thereby adapting to body tissue deformation at different pressure levels.
Solution Approach 2:
The invention changes the parameter of control target value from a constant fixed value to a variable value that changes with cuff pressure. By determining control target values at different pressure points and interpolating between them, the system adjusts the control parameter to compensate for body tissue deformation effects at different compression levels.
2Ease of operation
If the artery is compressed with a cuff to measure blood pressure, then the blood pressure can be measured non-invasively, but the body tissue deformation causes the measured pulse pressure difference to be smaller than the actual value
Solution Approach 1:
The system uses feedback from the arterial volume signal to dynamically adjust the control target value. The determination unit monitors the arterial volume changes and uses this feedback to determine appropriate control target values at different cuff pressure points, which compensates for the distorting effect of body tissue deformation on the pulse pressure measurement.
Solution Approach 2:
The invention introduces an intermediary processing step (interpolation by the change unit) between the raw arterial volume signal and the control target value. This intermediary process compensates for the distorting effects of body tissue deformation by calculating intermediate control target values that account for the non-linear relationship between cuff pressure and arterial volume changes.
3Measurement precision
If control target values are determined at diastolic and systolic blood pressure points and interpolated, then the measurement precision is improved, but the device complexity increases
Solution Approach 1:
The invention segments the blood pressure measurement range into distinct points (diastolic and systolic blood pressure points) and determines control target values at each segment point separately. The change unit then interpolates between these segmented points to provide continuous control target values, breaking down the complex problem into manageable segments.
Solution Approach 2:
The determination unit performs preliminary determination of control target values at key pressure points (diastolic and systolic) before actual blood pressure measurement. This preliminary action establishes reference points that guide the interpolation process, preparing the system in advance for accurate control during measurement.
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 device provides accurate blood pressure measurements by accounting for body tissue deformation, reducing measurement errors and enabling continuous, precise monitoring of blood pressure across the entire range of control pressures.
Implementation Method 1
an arterial volume sensor (70) having a light emitting element (71) and a light receiving element (72)
Data Source
AI summary
A blood pressure measurement device includes a cuff, inflation/deflation unit, pressure detection unit, volume detection unit, and control unit. The control unit determines values of an arterial volume signal detected by the volume detection unit, changes a prescribed control target value from the determined value at a time of diastolic blood pressure to a vicinity of the value at the time of systolic blood pressure during a rise time, changes the prescribed control target value from the determined value at the time of systolic blood pressure to a vicinity of the value at the time of diastolic pressure during a fall time, and adjusts the pressure of the cuff by controlling the inflation/deflation unit such that the volume indicated by the arterial volume signal detected by the volume detection unit matches the prescribed control target value. Thus, by applying a control target value, blood pressure can be measured.