Implantable Pressure Probe With Membrane-Based Temperature Compensation

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Solution Overview

Problem

Existing implantable pressure transducers are susceptible to temperature fluctuations, leading to measurement inaccuracies due to volume changes in the pressure transmission medium, and are limited by installation space and electrical isolation requirements, making them unsuitable for widespread medical applications.

Innovation Solution

A pressure sensor device with a catheter section containing a lumen filled with a temperature-controlled transmission fluid, featuring an elastic membrane and a tubular section designed to minimize stress on the membrane, allowing for accurate pressure measurement despite temperature changes and confined spaces.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If implantable pressure transducers are used, then direct blood pressure measurement is achieved, but temperature fluctuations cause volume changes in the pressure transmission medium leading to measurement inaccuracies

Engineering Contradiction:
Improvepressure measurement accuracyVSAvoidtemperature fluctuation influence
Core Design Contradiction:
Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The patent changes the physical parameters of the pressure transmission medium by selecting a gas-filled system with specific thermodynamic properties. The gas cushion absorbs temperature-induced volume changes through compression and expansion, maintaining pressure measurement accuracy despite temperature fluctuations in the implantable device.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent introduces a gas cushion as an intermediary between the pressure source and the transducer. This gas cushion acts as a buffer that decouples the direct mechanical connection, allowing temperature-induced volume changes to be absorbed without directly affecting the pressure measurement signal transmitted to the transducer.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If implantable pressure transducers are used, then pressure monitoring is achieved, but installation space is severely limited with transverse dimension not exceeding approximately 1 mm

Engineering Contradiction:
Improvepressure monitoring capabilityVSAvoidtransducer size
Core Design Contradiction:
ReliabilityVSVolume of moving object

Solution Approach 1:

The patent divides the pressure monitoring system into two separate components: a minimally invasive implantable probe containing only the pressure sensing element and gas cushion, and an external transducer unit. This segmentation allows the implantable portion to be extremely small (under 1 mm transverse dimension) while the larger transducer remains outside the body, maintaining pressure monitoring capability without violating size constraints.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent extracts the bulk of the transducer electronics and processing components from the implantable site and places them externally. Only the essential pressure sensing function and minimal gas cushion remain in the implantable probe, reducing the implantable volume to under 1 mm transverse dimension while preserving full pressure monitoring functionality through the external transducer connection.

Inventive Principle:
Principle #2Taking out (Extraction)

3Measurement precision

If implantable pressure transducers are used, then pressure measurement is achieved, but electrical isolation barrier requirements further limit available installation space

Engineering Contradiction:
Improvepressure measurement capabilityVSAvoidelectrical isolation requirements
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent extracts all electrical isolation barrier requirements from the implantable site by placing the transducer electronics externally. The implantable probe contains only passive mechanical elements (pressure sensing membrane and gas cushion) that require no electrical isolation, while the external transducer handles all electrical processing, eliminating the need for complex isolated barriers in the implantable component.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent replaces the traditional electrical-based pressure transduction system with a purely mechanical pressure transmission system using a gas cushion. This mechanical substitution eliminates the need for electrical isolation barriers entirely in the implantable portion, as the gas-transmitted pressure signal is read by an external transducer, simplifying the implantable device structure.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

4Reliability

If conventional housing with thick walls is used, then protection against temperature-related pressure fluctuations is provided, but the housing arrangement becomes less compliant and pressure measurements are distorted

Engineering Contradiction:
Improveprotection against temperature fluctuationsVSAvoidpressure measurement distortion
Core Design Contradiction:
ReliabilityVSMeasurement precision

Solution Approach 1:

The patent introduces a gas cushion as an intermediary that decouples the implantable probe from the external transducer. This gas cushion absorbs temperature-induced pressure fluctuations within the implantable housing, preventing them from being transmitted to the pressure measurement system, while allowing the housing walls to be thin and compliant for accurate pressure sensing.

Inventive Principle:
Principle #24Intermediary (Mediator)

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 device provides accurate pressure monitoring with minimal influence from temperature-related fluctuations, enabling cost-effective and safe in vivo applications without the need for electronic components, suitable for use in environments with electromagnetic interference.

Implementation Method 1

the lumen is filled with a transmission fluid, wherein the measuring tip comprises a tubular section with at least one laterally arranged opening, wherein the at least one opening is covered by an elastic membrane

Methodology Applied
Scientific EffectPressure transmission: Pascal's Law

Implementation Method 2

the at least one opening is covered by an elastic membrane

Methodology Applied
Scientific EffectElasticity: Elasticity

Data Source

PatentEP3829425B1Pressure sensor device for medical in vivo application, and method of manufacturing such device
Publication Date: 2025.08.13 EMKA MEDICAL GMBH
  • EP3829425B1 patent drawingFigure 1~2
  • EP3829425B1 patent drawingFigure 3~4
  • EP3829425B1 patent drawingFigure 5~7

AI summary

The invention relates to a pressure sensor device (1) for a medical in vivo application with at least one pressure transducer (2) and an implantable probe (3), wherein the probe (3) is proximally connected to the at least one pressure transducer (2), and the probe (3) also comprises a catheter section (4) and a measuring tip (5) on the distal end of the probe (3), the probe (3) having a longitudinal extension along the catheter section (4), wherein the catheter section (4) comprises at least one lumen (7) for producing a fluid connection from the measuring tip (5) to the pressure transducer (2), and the lumen (7) is filled with a transmission liquid, wherein the measuring tip (5) comprises a tubular section with at least one laterally arranged opening (9), the at least one opening (9) being covered with an elastic membrane (14), and wherein the filling quantity of the transmission liquid is determined such that, at a pre-determined temperature of the transmission liquid, the curvature of the membrane (14) transverse to the longitudinal extension is substantially aligned with the contour of the measuring tip (5) transverse to the longitudinal extension. The invention also relates to a measuring system and to a production method.