Doppler Catheter Transducer Nesting for Artery Velocity
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Solution Overview
Problem
Conventional methods for measuring arterial blood mean velocity and cardiac output are either inaccurate due to limitations in Doppler echocardiography or non-continuous in cardiac catheterization, making it difficult to obtain precise and continuous measurements, especially in certain body locations.
Innovation Solution
A cardiac output Doppler catheter system is introduced, where a Doppler transducer is placed within the artery to direct ultrasound waves parallel to blood flow, allowing for accurate measurement of blood mean velocity and continuous cardiac output monitoring, along with the ability to measure cross-sectional artery dimensions using additional transducers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If Doppler echocardiography is used to measure blood mean velocity, then non-invasive measurement is achieved, but measurement accuracy deteriorates due to angle limitations
Solution Approach 1:
The Doppler transducer is nested within the catheter body, allowing the transducer to be positioned inside the artery while the catheter provides structural support and access. This nesting enables the transducer to achieve optimal measurement angles (within 15 degrees of blood flow direction) that would be difficult to obtain from external positioning, thereby resolving the contradiction between non-invasive operation and measurement precision.
2Measurement precision
If conventional cardiac catheterization is used, then invasive access is achieved, but continuous measurement capability is lost
Solution Approach 1:
The catheter is designed with a flexible body and movable transducer that can be positioned and held continuously within the artery. The transducer can be advanced to the desired location and maintained in position for continuous measurement of blood flow parameters, eliminating the intermittent nature of conventional catheterization and enabling prolonged monitoring.
3Ease of operation
If Doppler transducer is positioned outside the artery, then non-invasive operation is maintained, but measurement accuracy deteriorates due to angle constraints
Solution Approach 1:
The Doppler transducer is nested within the catheter structure, allowing it to be positioned inside the artery lumen. This internal positioning enables the transducer to align its ultrasonic beam parallel to blood flow direction, achieving optimal Doppler angle (within 15 degrees) for accurate velocity measurement, which cannot be achieved from external positioning.
4Measurement precision
If transducer is inserted into the artery through conduit, then measurement accuracy is improved, but device complexity increases
Solution Approach 1:
The catheter body serves multiple functions: it provides structural support for insertion, houses the movable transducer mechanism, and facilitates positioning within the artery. The wires are designed to be movable within the conduit, allowing the transducer to be advanced to the measurement location and then withdrawn for signal processing. This multi-functionality reduces the need for separate components and simplifies the overall device architecture.
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
This approach enhances the accuracy of blood mean velocity measurement and enables continuous cardiac output monitoring, providing more reliable data for cardiac function assessment and management, particularly in newborns with cardiopulmonary issues.
Implementation Method 1
Conventional Doppler echocardiography used for measuring blood mean velocity in arteries employs a Doppler transducer outside the arteries to transmit ultrasound to the arteries
Implementation Method 2
employes a Doppler transducer outside the arteries to transmit ultrasound to the arteries
Data Source
Figure 1A~1B
Figure 2~3
Figure 4
AI summary
An apparatus for performing measurements in an artery includes a Doppler catheter, comprising a Doppler transducer and a wire connected to the Doppler transducer; and an elongated catheter body having a conduit therein for housing the wire of the Doppler catheter. The body has a proximal end and a distal end; wherein the wire is movable in the conduit relative to the catheter body so that the Doppler transducer and the wire are capable of being threaded into said conduit at the proximal end after the distal end of the catheter has been inserted into the artery, until the Doppler transducer emerges outside the conduit at the distal end of said body for performing ultrasound measurements in the artery. Another embodiment employs at least an additional side transducer for measuring the cross-sectional dimension of the artery useful for computing blood flow.