Perivascular Sensor for Blood Flow and Pressure Measurement
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Solution Overview
Problem
Current methods for measuring blood flow and pressure in blood vessels are invasive, prone to errors due to foreign object insertion, and unsuitable for long-term, accurate readings, with non-invasive tonometric methods facing technical challenges for implantable applications and perivascular ultrasound having limitations in continuous, real-time measurements.
Innovation Solution
A system using a single perivascular sensor that measures blood flow and pressure without penetrating the vessel wall, employing ultrasound transducers and a tonometric pressure sensor to obtain real-time, continuous readings by flattening the conduit surface for pressure measurement and using ultrasound beams at an oblique angle for flow measurement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a catheter with sensor is inserted into the blood stream for localized pressure measurement, then pressure measurement capability is achieved, but the invasive nature causes tissue formation around the catheter degrading measurement accuracy over time
Solution Approach 1:
The invention extracts the sensor from the invasive catheter approach and places it perivascularly outside the blood vessel. The sensor measures pressure by detecting the compliance of the vessel wall in response to external compression, eliminating the need for internal catheter insertion while maintaining measurement capability.
Solution Approach 2:
The invention introduces an intermediary approach where the sensor does not directly contact the blood or vessel wall interior, but instead measures pressure through the vessel wall's mechanical response to external compression. This intermediary measurement method avoids tissue rejection while maintaining accuracy.
2Reliability
If a catheter is inserted into the blood vessel for flow and pressure measurement, then real-time measurements are obtained, but the foreign object causes immune response and tissue formation degrading long-term measurement capability
Solution Approach 1:
The sensor is extracted from the blood vessel interior and positioned perivascularly outside the vessel. This eliminates the foreign body effect and immune response caused by internal catheter insertion, allowing long-term reliable measurements without tissue rejection.
Solution Approach 2:
The invention replaces the mechanical intrusion of a catheter with a non-invasive mechanical measurement approach. Instead of inserting a sensor into the vessel, the system uses external compression and measures the vessel wall's compliance response, substituting direct mechanical contact with indirect mechanical measurement.
3Ease of operation
If tonometric pressure measurement is used by pressing a sensor against the outside of a vessel, then non-invasive pressure measurement is achieved, but technical problems prevent its adoption as an implantable method for localized blood pressure measurement
Solution Approach 1:
The invention segments the measurement function into two parts: external compression applied to the vessel and compliance measurement of the vessel wall response. This segmentation allows the sensor to measure localized pressure at a specific vessel location without requiring invasive insertion, combining non-invasive operation with accurate localized measurement.
Solution Approach 2:
The invention changes the measurement parameter from direct pressure sensing to compliance measurement. By measuring how the vessel wall deforms in response to external compression, the system indirectly determines pressure with high accuracy while maintaining non-invasive operation and implantable capability.
4Productivity
If perivascular ultrasound measurement is used for blood flow measurement, then non-invasive flow measurement is achieved, but continuous real-time measurements over extended periods cannot be made without loss of accuracy
Solution Approach 1:
The invention merges the ultrasound flow measurement capability with the perivascular pressure sensor into a single integrated device. This combination allows simultaneous or sequential measurement of both flow and pressure at the same location, enabling continuous real-time monitoring while maintaining accuracy through a stable perivascular position.
Solution Approach 2:
The perivascular sensor is positioned and secured outside the blood vessel before measurement begins. This preliminary positioning ensures stable contact with the vessel wall, eliminating the need for repeated repositioning and maintaining measurement accuracy over extended continuous monitoring periods.
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 real-time, continuous, and accurate measurements of blood flow and pressure over extended periods without invasive procedures, allowing for the calculation of tissue or organ impedance, reducing tissue rejection and maintaining measurement accuracy.
Implementation Method 1
making a volume flow or flow velocity measurement using an ultrasound wave beam passed into a conduit at an oblique angle to the a fluid flowing in the conduit
Implementation Method 2
flattening a portion of the conduit
Data Source
AI summary
A system and method for measuring fluid flow and pressure in a flexible conduit is disclosed. An embodiment of the system and method uses an ultrasound sensor for determining volume of flow and a tonometric system for determining pressure along a common length of a flexible conduit.