Removable Pressure Sensor for Extracorporeal Circulation
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Solution Overview
Problem
Existing pressure sensors for extracorporeal circulation circuits require complex setup and risk thrombus formation due to the need for a bifurcated liquid flow path and chamber filling, making instantaneous pressure measurement challenging and unsafe during cardiac surgery.
Innovation Solution
A removable pressure sensor with a main body featuring a tube mounting recessed portion that elastically deforms the tube, allowing pressure measurement without a liquid flow path or chamber filling, and includes a temperature sensor for pressure correction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a bifurcated liquid flow path and liquid chamber are used for pressure measurement, then pressure measurement capability is achieved, but device complexity and thrombus formation risk increase
Solution Approach 1:
The invention extracts the pressure measurement function from the liquid flow path structure. Instead of using a bifurcated flow path with a liquid-filled chamber, the patent uses a solid-state pressure sensor that directly contacts the tube wall. This eliminates the complex liquid flow path structure while maintaining pressure measurement capability through direct mechanical contact with the tube.
Solution Approach 2:
The invention replaces the mechanical liquid-filled chamber system with an electronic pressure sensor system. The pressure sensor uses electrical components (strain gauges, piezoelectric elements, or capacitive sensors) to detect pressure through tube wall deformation, substituting the mechanical liquid transmission system with an electronic measurement system that is simpler and safer.
2Measurement precision
If a bifurcated liquid flow path is formed in the tube, then pressure measurement is enabled, but thrombus formation risk increases
Solution Approach 1:
The invention removes the liquid-filled chamber and bifurcated flow path from the measurement system. By using a pressure sensor that contacts only the external surface of the tube, the system eliminates stagnant liquid regions where thrombus formation occurs, while still enabling pressure measurement through tube wall deformation detection.
Solution Approach 2:
The tube wall itself serves as an intermediary between the liquid and the pressure sensor. Instead of requiring direct contact between the sensor and liquid (which creates stagnant regions), the tube wall transmits pressure information to the sensor through elastic deformation, acting as a safe intermediary that prevents thrombus formation while enabling measurement.
3Measurement precision
If manual filling of liquid chamber is required, then pressure measurement setup is completed, but operational time and complexity increase
Solution Approach 1:
The pressure sensor system is self-contained and requires no external liquid filling operation. The sensor automatically detects pressure through tube wall deformation as blood flows through the tube, eliminating the manual filling step entirely. The system serves itself by using the tube's natural deformation under blood pressure to generate the measurement signal.
Solution Approach 2:
The pressure sensor is pre-mounted on the tube exterior before the extracorporeal circulation begins. This preliminary positioning allows immediate pressure measurement as soon as blood flows through the tube, eliminating the need for time-consuming setup operations during the surgical procedure.
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 simple, instantaneous, and safe measurement of intra-circuit pressure without thrombus formation, improving operational efficiency and safety during extracorporeal circulation.
Implementation Method 1
a tube mounting recessed portion 34 into which an intermediate part of the tube 11 is removably fitted, whereupon the tube 11 is elastically deformed
Data Source
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AI summary
[Problem] Provided are a removable pressure sensor which can simply, instantaneously, and safely measure an intra-circuit pressure of a liquid circulating in a circuit, and an extracorporeal circulator provided with a removable pressure sensor. [Means for Resolution] A removable pressure sensor 30 includes a main body portion 31 and a pressure measurement element 40 that is disposed in the main body portion 31. The main body portion 31 has a base portion 32 which has a tube mounting recessed portion 34 such that an intermediate part of a tube 11 (12, 19) is removably fitted, the tube 11 (12, 19) is elastically deformed, and the pressure measurement element 40 measures a circuit pressure of a liquid inside the tube 11 (12, 19); and a lid portion 33 which holds the tube 11 (12, 19) inside the tube mounting recessed portion 34 by closing the tube mounting recessed portion 34 of the base portion. The tube mounting recessed portion 34 has a rectangular cross section, and a width L of the rectangular cross section is configured to be smaller than an external dimension D of the tube.