Electronic Sphygmomanometer Circumferential Length Estimation
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Solution Overview
Problem
Conventional methods for non-invasive blood pressure measurement using cuff bands face challenges such as measurement errors due to inappropriate cuff widths, increased production costs, and complexity from additional detecting functions or resistance measurements, and errors in estimating circumferential length during pressurization.
Innovation Solution
An electronic sphygmomanometer with a cuff band containing a fluid bag, an electric depressurizing valve, and a drive circuit that regulates the depressurizing speed to estimate the circumferential length using previously set basic data, allowing for accurate blood pressure measurement without additional detecting functions or complex mechanisms.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If additional detecting functions or resistance measurement mechanisms are added to the cuff band to measure circumferential length, then measurement precision is improved, but device complexity and production costs increase
Solution Approach 1:
The patent replaces mechanical detection mechanisms (sliding resistors, additional sensors) with a computational approach. The circumferential length is calculated using the correlation formula between pressure pump discharge quantity and circumferential length, combined with pressure sensor data during the pressurization process. This eliminates the need for mechanical measuring components in the cuff band while achieving accurate measurement.
Solution Approach 2:
The system uses the existing pressurization process and pressure sensor already required for blood pressure measurement to simultaneously obtain circumferential length information. The discharge quantity of the pressure pump during normal operation serves dual purposes: both pressurizing the cuff for blood pressure measurement and providing data for circumferential length calculation, eliminating the need for separate measurement mechanisms.
2Adaptability or versatility
If multiple cuff bands with different widths are prepared to cover various circumferential lengths, then adaptability is improved, but device complexity and selection complexity increase
Solution Approach 1:
The patent changes the approach from physical adaptation (multiple cuff sizes) to computational adaptation (correction based on measured parameters). By measuring the actual circumferential length and applying the appropriate correction value from the correlation data, a single cuff band design can accurately measure blood pressure across different arm sizes without requiring multiple physical variants.
Solution Approach 2:
The single cuff band design becomes universal by incorporating the circumferential length measurement and correction capability. Instead of requiring different cuffs for different arm sizes, one cuff band can serve all users by automatically determining the appropriate measurement parameters and applying corrections based on the measured circumferential length.
3Ease of operation
If the circumferential length is estimated based on pressurization time to a specific pressure, then ease of operation is improved, but measurement precision deteriorates due to operational fluctuations
Solution Approach 1:
The system implements feedback control by continuously monitoring the actual pressure during pressurization and using the measured discharge quantity to calculate circumferential length. Rather than relying on fixed pressurization time assumptions, the system uses real-time pressure feedback and discharge quantity data to accurately determine circumferential length, compensating for variations in pressurization rate and operational conditions.
Data Source
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AI summary
To provide an electronic sphygmomanometer capable of accurately obtaining a circumferential length of a measurement site without providing a complicated mechanism of a cuff band or pressurizing means for the cuff band. The electronic sphygmomanometer includes a cuff band (20) wrapped around a measurement site; a fluid bag (201) internally included in the cuff band (20); pressurizing means (102, 111) for pressurising an inside of the fluid bag (201); an electric depressurizing valve (103) for depressurizing an inside of the fluid bag (201); an electric depressurizing valve drive circuit (112) for regulating a drive energy amount of the electric depressurizing valve (103); and circumferential length estimating means (124) for obtaining a circumferential length of the measurement site by using a drive energy amount regulated by the electric depressurizing valve drive circuit (112) and previously set basic data.