Wearable Tonometer Radial Artery Sensor Array
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Solution Overview
Problem
Existing wearable tonometers face challenges in accurately measuring arterial blood pressure due to cross-talk between sensors, movement artifacts, and nonlinearity in force transmission, leading to noisy and unreliable signals.
Innovation Solution
A wearable tonometer design featuring a detection group with multiple pressure sensors and a touching group made of materials with an elastic constant greater than the radial artery, combined with an adjusting device and a locking mechanism to maintain constant force and correct positioning, reducing cross-talk and noise, and enhancing signal accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple pressure sensors are used to detect arterial blood pressure, then the reliability of measurement is improved, but cross-talk between sensors occurs causing measurement errors
Solution Approach 1:
A touching group made of stiff material is introduced as an intermediary between the pressure sensors and the radial artery. This touching group transmits the arterial pressure forces to the sensors while its stiff material composition prevents signal distortion and cross-talk between adjacent sensors, thereby maintaining measurement reliability without harmful interference
Solution Approach 2:
The touching group is designed with localized stiff material properties at specific contact points with the artery. Each contact point has optimized local mechanical characteristics that match the arterial wall properties, ensuring accurate local pressure detection while preventing signal leakage to adjacent sensors
2Ease of operation
If the tonometer is made wearable and movable, then the ease of operation is improved, but the positioning accuracy deteriorates causing loss of artery signal
Solution Approach 1:
The tonometer is segmented into a wearable support body with multiple independent sensor units arranged in an array. This segmentation allows the device to be worn comfortably while maintaining multiple potential detection points, so that if one sensor loses contact with the artery, others can still detect the signal
Solution Approach 2:
The control unit dynamically selects the optimal sensor from the array based on real-time signal quality assessment. As the patient moves, the system adapts by identifying which sensor maintains the best contact with the radial artery, ensuring continuous accurate measurement despite positioning changes
3Ease of manufacture
If soft materials like silicone rubber are used between sensors and artery, then the ease of manufacture is improved, but the measurement precision deteriorates due to nonlinearity in force transmission
Solution Approach 1:
The material parameter (elastic constant) of the touching group is changed from soft materials like silicone rubber to stiff materials with elastic constant greater than that of the radial artery. This parameter change ensures linear force transmission from the artery to the sensors, maintaining measurement precision while still allowing for manufacturable designs
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 significantly improves signal sensitivity and accuracy by reducing cross-talk between sensors and maintaining consistent force application, ensuring reliable and precise arterial blood pressure monitoring.
Implementation Method 1
a touching group (60) interposed, in use, between said sensors (25) and said radial artery (101)... each connection portion (63a-63d) configured such that the respective protuberant member (65a-65d) is able to elastically move along a direction (165a-165d) substantially orthogonal to the base portion (61)
Data Source
Figure 1~2
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Figure 5~6
AI summary
An improved tonometer (1) for continuously monitoring the arterial blood pressure of a patient for a predetermined period of time comprises a bracelet (10) configured in such a way to be applied to a wrist of a patient (100). It is, furthermore, provided a detection group (20) mounted on the bracelet (10) and arranged to detect a pressure signal. The detection group (20) comprises a plurality of pressure sensors (25) arranged to detect a respective pressure signal associated to the blood pressure wave of the patient (100). At least one pressure sensor (25) is positioned, in use, in proximity of the radial artery of the patient (100), at the opposite side of the radial bone. It is, also, provided a touching group (60) that is interposed, in use, between the detection group (20) and the radial artery of the patient and equipped with a plurality of protuberant members (65a-65d), each of which associated to a respective pressure sensor (25) and arranged to be positioned, in use, into contact with the skin of the patient, in such a way to exert a predetermined force F on the radial artery.