Wireless Pressure Sensor for Extracorporeal Blood Circuits
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Solution Overview
Problem
Existing medical pressure sensing systems in extracorporeal blood circuits face challenges such as cross-contamination, leakage, and electrical safety issues due to the presence of blood and contaminants, leading to inaccurate pressure measurements and risks to operators.
Innovation Solution
A wireless pressure sensing system using a compressible container with a capacitance or inductance-based resonance circuit that communicates pressure information via alternating electromagnetic fields, eliminating the need for direct electrical connections and minimizing the air-blood interface.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If an ordinary pressure transducer is used in the dialysis machine with an air column separator, then pressure sensing is achieved, but cross-contamination risk increases due to potential blood contact with the pressure sensor
Solution Approach 1:
The pressure sensor is extracted from the reusable dialysis machine and integrated into the disposable blood circuit cartridge. This separation ensures that the pressure sensor is disposed of with the single-use circuit, eliminating the risk of cross-contamination while maintaining accurate pressure sensing capability.
Solution Approach 2:
The pressure sensor is made part of a disposable cartridge that is discarded after a single use. This approach eliminates cross-contamination risks by ensuring the sensor never contacts blood from multiple patients, while the low cost of the disposable sensor makes this economically viable.
2Loss of information
If electrical connectors and wiring are used to transmit pressure information, then pressure data can be conveyed, but the risk of fluid spillage and contamination increases due to edges and indentations in connectors
Solution Approach 1:
The mechanical electrical connector system is replaced with optical communication (LED and photodetector). This substitution eliminates edges and indentations where blood could accumulate, while maintaining the ability to transmit pressure information through light signals across an air gap.
Solution Approach 2:
An air gap acts as an intermediary medium between the LED and photodetector, allowing optical signal transmission without direct physical contact. This eliminates the need for electrical connectors that create contamination risks while preserving data transmission functionality.
3Ease of operation
If electrical connectors are exposed for operator connection, then system setup is possible, but operator safety is compromised due to electric shock risk
Solution Approach 1:
Electrical connectors are replaced with optical components (LED and photodetector) that operate at safe voltage levels. This substitution maintains ease of setup through simple alignment while eliminating the electric shock hazard associated with exposed electrical connectors.
4Object-affected harmful factors
If a protective filter is placed to prevent blood contact with the pressure sensor, then cross-contamination is reduced, but bacteria growth may occur in blood residuals at the filter
Solution Approach 1:
The pressure sensor is extracted from the reusable machine and integrated into the disposable cartridge, eliminating the need for a protective filter. This removes the trapping of blood residuals that could support bacterial growth, while maintaining cross-contamination prevention through single-use disposal.
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 solution reduces the risk of cross-contamination, simplifies setup, prevents leakage, and provides accurate pressure measurements while ensuring electrical safety, allowing for disposable and inexpensive sensors that can be used in various medical procedures.
Implementation Method 1
the container is compressible, the compression or expansion of which is indicative of the pressure
Implementation Method 2
comprises an electric circuit that is configured to be energized by an applied alternating first electromagnetic field and configured to communicate information indicative of a pressure from the pressure sensor via a second alternating electromagnetic field
Data Source
AI summary
A biological fluid device (703) comprises a pressure sensor (702), which is arranged on the device. The pressure sensor comprises a compressible container, the compression of which is indicative of the pressure, and is capable of wireless communication.