Blood Flow Control Apparatus Using Pump Angular Velocity
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Solution Overview
Problem
Existing blood treatment systems rely on peristaltic pumps for controlling blood flow in extracorporeal circuits, but they require continuous measurement and adjustment of parameters to achieve accurate flow control, which is inefficient and can lead to unsafe operating conditions.
Innovation Solution
An apparatus with sensors and a control unit that calculates and sets the angular velocity of the peristaltic pump based on pre-loaded mathematical relations specific to the vascular access, allowing for accurate blood flow control without continuous measurement or periodic adjustments, and provides warnings for potentially dangerous conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If continuous measurement and adjustment of parameters is performed to achieve accurate flow control, then measurement precision is improved, but device complexity and operational burden increase
Solution Approach 1:
The patent applies preliminary action by performing calibration before the actual blood treatment procedure. During calibration, the system determines the relationship between pump angular velocity and actual blood flow by measuring flow at multiple angular velocity settings and storing this data in a lookup table. This pre-computed calibration data eliminates the need for continuous measurement and adjustment during treatment, as the system can directly query the pre-determined relationship to calculate flow based on angular velocity and pressure readings.
2Reliability
If continuous monitoring is performed to maintain safe operating conditions, then reliability is improved, but loss of time and operational efficiency decrease
Solution Approach 1:
The system performs preliminary calibration to establish the relationship between pump angular velocity and actual blood flow before treatment begins. During treatment, the system only needs to read the current angular velocity from the pump and the upstream pressure from a pressure sensor, then queries the pre-computed calibration data to calculate the actual flow. This eliminates continuous monitoring and adjustment operations, maintaining reliability while significantly reducing time loss.
Solution Approach 2:
The system uses the pump's own angular velocity reading and the pressure sensor reading to self-calculate the actual blood flow using the calibration data. This self-service approach eliminates the need for external continuous monitoring systems or manual adjustments, as the system automatically determines flow based on its own operational parameters and the pre-established calibration relationship.
3Ease of operation
If simple proportional calculation is used for flow based on pump angular velocity, then ease of operation is improved, but measurement precision deteriorates due to errors from varying factors
Solution Approach 1:
The system performs preliminary calibration measurements at multiple angular velocity settings to determine the actual relationship between pump rotation and blood flow under specific conditions (including particular tubing configurations, access organ characteristics, and pressure conditions). This calibration data is stored in a lookup table that captures the non-linear relationship between angular velocity and flow. During treatment, the system uses this pre-determined relationship to calculate actual flow, achieving both ease of operation (simple lookup and calculation) and measurement precision (accurate flow values accounting for varying factors).
Solution Approach 2:
The system accounts for parameter changes by performing calibration under specific conditions (including particular tubing configurations, access organ characteristics, and pressure conditions) and using this calibrated relationship during treatment. The calibration process captures how the relationship between angular velocity and flow changes with different operating parameters, allowing the system to maintain precision across varying conditions without complex real-time adjustments.
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 precise and safe blood flow control before treatment, reducing the need for continuous monitoring and minimizing the risk of adverse reactions by setting optimal pump conditions based on patient-specific parameters.
Implementation Method 1
There is usually a peristaltic pump located at the access branch, which pump is destined to act on the access branch in order progressively to move the blood flow towards the treatment unit
Data Source
AI summary
The apparatus for blood flow control in an extracorporeal circuit comprises: a user interface for setting a desired blood flow value (qbREAL) and a datum relating to the vascular access, a memory for recording a plurality of mathematical relations having mathematical expressions relating to the vascular access organ to be used, and a control unit. The control unit identifies the vascular access, selects, from among the plurality of mathematical relations present in the memory, a relation which corresponds to the vascular access identified, and calculates, as a mathematical function of the set value for the desired flow (qbREAL), a value at which to set the angular velocity of the pump associated to the extracorporeal circuit and/or a theoretical value of the arterial pressure upstream of the pump.