Optical Pressure Sensing Guidewire for Accurate Blood Pressure Measurement
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Solution Overview
Problem
Current medical devices for measuring blood pressure within blood vessels lack effective solutions for accurate and flexible pressure sensing, particularly in navigating tortuous anatomy and avoiding deformations that can lead to pressure reading offsets.
Innovation Solution
A pressure sensing guidewire with an elongated shaft and an optical pressure sensing block, featuring a pressure sensing membrane and an optical fiber connector, is designed to measure blood pressure, incorporating a central portion that spaces the sensing membrane away from the lumen and a tip member with a shaping or coil member for flexibility and reduced contact with the vessel wall.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the pressure sensing membrane is positioned close to the lumen for compact design, then device size is reduced, but the sensor contacts the vessel wall causing pressure reading offsets
Solution Approach 1:
The patent introduces a longitudinal dimension (z-axis) separation between the pressure sensing membrane and the lumen by positioning the membrane in the distal region while the lumen extends through the proximal region. This spatial separation in the longitudinal dimension prevents contact between the sensor and vessel wall while maintaining device functionality.
Solution Approach 2:
The patent introduces a fluid-filled chamber as an intermediary medium between the pressure sensing membrane and the external environment. This intermediary allows pressure transmission to the sensor without direct contact between the sensor and the vessel wall or surrounding tissues.
2Adaptability or versatility
If the guidewire is made flexible to navigate tortuous anatomy, then navigability is improved, but the sensor becomes more susceptible to deformations causing reading offsets
Solution Approach 1:
The patent employs a flexible membrane structure for the pressure sensing element that can deform with the guidewire during navigation but maintains its functional integrity. The membrane is designed to be flexible enough to accommodate guidewire bending while rigid enough to accurately sense pressure changes.
Solution Approach 2:
The patent changes the physical parameters of the pressure sensing membrane, specifically its thickness, material composition, and structural configuration, to optimize the balance between flexibility and measurement accuracy. By adjusting these parameters, the membrane can withstand deformations during navigation while maintaining sensing precision.
3Manufacturing precision
If the pressure sensor is positioned in the distal region for accurate local measurement, then measurement location precision is improved, but the optical fiber alignment becomes more difficult
Solution Approach 1:
The patent incorporates the optical fiber and its alignment features during the initial manufacturing of the guidewire assembly, before the final assembly step. The optical fiber is pre-positioned and secured within the guidewire structure, allowing for precise alignment to be established during manufacturing rather than during final assembly or clinical use.
Solution Approach 2:
The patent merges the optical fiber connector with the pressure sensing membrane assembly, creating an integrated component where the fiber alignment features are built into the membrane holder structure. This integration simplifies the alignment process by reducing the number of separate components that need to be precisely positioned relative to each other.
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 guidewire provides accurate blood pressure measurements by minimizing contact between the pressure sensor and the vessel wall, reducing deformations and thus avoiding pressure reading offsets, while maintaining flexibility for navigating complex vascular structures.
Implementation Method 1
an optical fiber extending through the lumen and coupled to the optical fiber connector
Implementation Method 2
a pressure sensing membrane disposed on the distal portion of the optical pressure sensing block
Data Source
AI summary
Medical devices and methods for making and using medical devices are disclosed. An example medical device may include a medical device for measuring blood pressure. The medical device may include an elongated shaft having a proximal region and a distal region and a lumen extending therethrough and an optical pressure sensing block disposed within the lumen, the optical pressure sensing block including a distal portion bearing a pressure sensing membrane and a proximal portion forming an optical fiber connector extending proximally from the proximal portion. The optical fiber connector may be configured to be coupled to an optical fiber extending through the lumen.