Flexible Bubble Measuring Device for Continuous Cardiovascular Monitoring
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Solution Overview
Problem
Current non-invasive methods for continuously measuring cardiovascular parameters, such as blood pressure, face challenges including the need for calibration with a cuff, interference from physiological events, and prolonged compressive loads on the body, often requiring multiple sensors or frequent recalibration.
Innovation Solution
A measuring device and method that utilize a single sensor to briefly apply pressure during a measurement phase, calibrate a mathematical model using cardiovascular values, and then reduce pressure to interpolate parameters without continuous exertion, allowing for continuous monitoring of arterial blood pressure and other cardiovascular parameters using machine learning and minimal contact pressure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of stationary object
If continuous pressure is applied to the extremity for monitoring blood pressure, then continuous measurement is achieved, but prolonged compressive loads are exerted on the body
Solution Approach 1:
The patent implements periodic measurement phases where the bladder is inflated to a calibration pressure for a brief period to obtain absolute blood pressure values, followed by deflation to a low residual pressure for continuous monitoring. This periodic inflation-deflation cycle allows continuous measurement capability while significantly reducing the duration of harmful compressive loads on the extremity.
2Measurement precision
If cuff-based calibration is used to determine absolute blood pressure values, then accurate calibration is achieved, but additional sensors and complex setup are required
Solution Approach 1:
The patent enables the single sensor system to perform its own calibration by temporarily inflating the bladder to a known calibration pressure that occludes the artery. During this brief calibration phase, the sensor measures the relationship between the applied pressure and the occluded state, allowing the system to self-calibrate and determine absolute blood pressure values without requiring separate cuff-based calibration equipment or additional sensors.
3Measurement precision
If physiological events such as vasoconstriction and vasodilation occur, then blood pressure calculation accuracy deteriorates, but frequent recalibration is required
Solution Approach 1:
The patent employs feedback mechanisms where the sensor continuously monitors pulsatile blood flow signals and detects changes in vascular tone through analysis of pulse wave characteristics. When vasoconstriction or vasodilation is detected, the system automatically triggers a recalibration sequence by inflating the bladder to the calibration pressure, thereby maintaining measurement accuracy without requiring predetermined recalibration schedules.
4Device complexity
If a single sensor is used for measurement, then device complexity is reduced, but the ability to determine absolute blood pressure values is limited
Solution Approach 1:
The patent transforms the static limitation of a single sensor into a dynamic solution by implementing a controllable inflation system. The bladder is dynamically inflated to a calibration pressure that temporarily occludes the artery, creating a known reference state. During this dynamic calibration phase, the single sensor measures the relationship between applied pressure and blood flow occlusion, enabling it to calculate absolute blood pressure values that would normally require multiple sensors.
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
Enables continuous, non-invasive determination of cardiovascular parameters with reduced long-lasting compressive loads, using a compact system that can be integrated into a wearable unit, providing accurate and efficient monitoring with minimal error detection and adaptive recalibration.
Implementation Method 1
a flexible, fluid-filled bladder, which is supported on the recording element and acts on the extremity
Data Source
AI summary
The invention relates to a method and a measuring device for continuously non-invasively determining at least one cardiovascular parameter, preferably the arterial blood pressure, at an extremity containing an artery, the measuring device comprising a receiving element that can be attached to the extremity and is suited to at least partly surround the extremity, and comprising a flexible bubble which is supported on the receiving element, acts on the extremity and is filled with a fluid. According to the invention, an actuator which is suited to vary the pressure in the flexible bubble is placed in or on the receiving element, and the flexible bubble includes a pressure sensor which is in contact with the fluid in the flexible bubble and which is suited to continuously measure the absolute pressure value. The measuring device further comprises a unit suited to measure the pulsations generated by the volume flow in the artery, and a control unit having two different modes of operation, i.e. a measuring phase and an interpolation phase.