Forearm Pressure Cuff With Sensing Pad for Obese Blood Pressure Measurement
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Solution Overview
Problem
Existing blood pressure measurement devices struggle to accurately measure physiological parameters in obese subjects due to increased fat layers obscuring signal quality, particularly in conventional oscillometric cuffs.
Innovation Solution
A pressure measuring device with a fluid-filled pressure sensing pad, preferably gas-filled, positioned along the middle of a shell surrounding the body part, focusing on distal body parts like the forearm or lower leg, and using a kinking-proof shell to maintain accurate pressure application and measurement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a conventional oscillometric cuff is used with a single component for both pressure application and measurement, then the device structure is simple, but the measurement precision deteriorates due to inability to accurately reflect blood pulsations
Solution Approach 1:
The cuff is divided into functionally separate components: a pressure application element (bladder) for applying occlusion pressure, a shell for structural support and shape maintenance, and a pressure sensing device with sensing element for detecting blood pulsations. This segmentation allows each component to be optimized for its specific function, improving measurement precision while maintaining reasonable device complexity.
Solution Approach 2:
The shell acts as an intermediary component positioned between the pressure application element and the body part. It maintains the cuff's shape and ensures uniform pressure distribution while allowing the sensing element to accurately detect tissue pressure pulses, thereby improving measurement accuracy without requiring direct contact between the sensing element and the body.
2Adaptability or versatility
If measurements are taken on proximal body parts with significant fat layers, then the device can be used on obese subjects, but the measurement precision deteriorates due to decreased signal quality from increased fat between skin and inner vessels
Solution Approach 1:
The device replaces the traditional oscillometric detection method with a direct tissue pressure pulse detection approach. The pressure sensing device measures the actual pressure pulses in the tissue caused by blood flow, rather than relying on oscillations transmitted through fat and tissue layers. This substitution of measurement principle maintains high signal quality even in obese subjects with significant fat layers.
3Measurement precision
If a fluid-filled pressure sensing pad is used, then the measurement precision improves by accurately reflecting blood pulsations, but the device complexity increases due to additional fluid filling and sealing requirements
Solution Approach 1:
The pressure sensing device uses a fluid-filled (preferably gas-filled) pressure sensing pad that transmits tissue pressure pulses to the sensing element through fluid pressure. This pneumatic/hydraulic coupling allows accurate detection of blood pulsations while the fluid also provides cushioning and uniform pressure distribution. The simplicity of using common fluids like air or water keeps the implementation straightforward despite the added functional complexity.
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 achieves high signal-to-noise ratio and accurate blood pressure measurements by minimizing hydrostatic pressure errors and adapting to individual body shapes, reducing production costs while maintaining measurement accuracy.
Implementation Method 1
a fluid-filled pressure sensing pad arranged in a pressure sensing area extending along a middle of an inner surface of the shell
Implementation Method 2
a pressure application element configured to apply pressure to the body part
Data Source
Figure 1
Figure 2
Figure 3A
AI summary
The invention relates to a pressure measuring device 6 configured to surround a subject's body part 5, wherein the pressure measuring device comprises a) a pressure application element 88 configured to apply pressure to the body part, and b) a shell 4 arranged to be located between the pressure application element and the body part, when the pressure measuring device surrounds the body part 5. Furthermore, the pressure measuring device comprises c) a pressure sensing device comprising a fluid-filled pressure sensing pad 61 arranged in a pressure sensing area 72 extending, as measured in a proximal-distal direction 83, along a middle of an inner surface of the shell, wherein the pressure sensing device is configured to measure a pressure signal indicative of blood pulsations in the subject. The pressure measuring device allows for an accurate measurement of a physiological parameter like blood pressure, even if the subject is severely obese.