Implantable MEMS Sensor for Cardiac Pressure Monitoring

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Solution Overview

Problem

Invasive pulmonary artery catheterization for postoperative hemodynamic monitoring is costly and carries morbidity, and existing implantable wireless sensors require invasive procedures and battery maintenance.

Innovation Solution

A miniature implantable sensing system with a sensing unit and anchor designed for minimally invasive placement in an organ's external wall, using a batteryless MEMS sensor and telemetry antenna for real-time, continuous monitoring of physiological parameters, with a readout device for wireless communication and power supply.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If pulmonary artery catheterization is used for postoperative hemodynamic monitoring, then physiological parameters can be monitored, but the procedure is invasive, expensive, and carries morbidity

Engineering Contradiction:
Improvephysiological parameter monitoringVSAvoidinvasiveness and morbidity
Core Design Contradiction:
Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The device is divided into two separate components: a minimally invasive implantable sensor placed in the heart chamber and an external reader unit. This segmentation allows the sensing function to be performed inside the body with minimal intrusion while the complex processing and power supply functions are located outside the body, eliminating the need for invasive catheterization procedures.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent replaces the mechanical catheter-based sensing system with a wireless electromagnetic communication system. The implantable sensor uses an antenna to transmit physiological data wirelessly to the external reader, eliminating the need for physical catheter insertion and mechanical connections that cause morbidity.

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

2Duration of action of moving object

If implantable wireless sensors are used for monitoring, then continuous monitoring is enabled, but the devices require battery maintenance and invasive procedures

Engineering Contradiction:
Improvecontinuous monitoring capabilityVSAvoidbattery maintenance requirement
Core Design Contradiction:
Duration of action of moving objectVSEase of operation

Solution Approach 1:

The implantable sensor is designed to be powered wirelessly by the external reader unit through electromagnetic induction. The sensor draws power during each interrogation cycle without requiring an internal battery, eliminating the need for battery replacement or recharging. The device serves itself by harvesting energy from the external reader's electromagnetic field during normal operation.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The system operates in periodic cycles where the external reader wirelessly powers the implantable sensor and retrieves data in discrete intervals. This periodic operation allows the sensor to remain passive between interrogations, consuming no power, and enables continuous monitoring over long periods without battery maintenance.

Inventive Principle:
Principle #19Periodic action

3Measurement precision

If sensors are placed within heart chambers for pressure monitoring, then accurate cardiac pressure measurement is achieved, but thrombogenesis risk increases

Engineering Contradiction:
Improvecardiac pressure measurement accuracyVSAvoidthrombogenesis risk
Core Design Contradiction:
Measurement precisionVSObject-generated harmful factors

Solution Approach 1:

The implantable sensor incorporates a flexible membrane or diaphragm that directly contacts the blood while the electronic components are sealed in a biocompatible housing. This thin film structure allows accurate pressure transmission from the blood to the sensor while minimizing the sensor's physical footprint and surface area in contact with blood, thereby reducing thrombogenesis risk.

Inventive Principle:
Principle #30Flexible shells and thin films

Solution Approach 2:

The sensor design allows for minimal protrusion into the blood flow and uses a compliant structure that moves with the cardiac cycle rather than rigidly disrupting blood flow. The flexible membrane dynamically responds to pressure changes while maintaining blood flow patterns, reducing the risk of thrombus formation compared to rigid fixed structures.

Inventive Principle:
Principle #15Dynamics

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 safe, fast, and continuous monitoring of cardiac pressures and other parameters without the need for invasive procedures or battery replacement, reducing thrombogenesis risk and allowing long-term, maintenance-free operation.

Implementation Method 1

a sensing device having a sensing element adapted to sense a physiological parameter within an organ

Methodology Applied
Scientific EffectPressure sensing:

Implementation Method 2

using a batteryless MEMS sensor and telemetry antenna for real-time, continuous monitoring of physiological parameters, with a readout device for wireless communication

Methodology Applied
Scientific EffectElectromagnetic radiation:

Data Source

PatentEP2139385B1System for monitoring a physiological parameter within an internal organ of a living body
Publication Date: 2014.10.29 INTEGRATED SENSING SYSTEMS INC
  • EP2139385B1 patent drawingFigure 1a~1b
  • EP2139385B1 patent drawingFigure 2a~3
  • EP2139385B1 patent drawingFigure 4~6

AI summary

A system and surgical procedure for monitoring physiological parameters within an internal organ of a living body. The procedure entails making a first incision to expose the organ and a second incision through an external wall (134) of the organ and into an internal cavity (136). A sensing unit (150A-C) is placed in the second incision such that a proximal end thereof remains outside the organ. The unit (150A-C) includes a sensing device (60) having a sensing element (62,94) for sensing the physiological parameter within the organ, and an anchor (120A-C) to which the sensing device (60) is secured. The unit (150A-C) occludes the second incision and a distal end (112,126) of the unit (150A-C) does not extend more than one centimeter into the cavity (136). The anchor (120A-C) is then secured to the wall (134) of the organ, after which the first incision is closed and a readout device (80) telemetrically communicates with the sensing device (60) to obtain a reading of the physiological parameter.