Magnetic Levitation Blood Pump Flow Rate Estimation
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Solution Overview
Problem
Direct blood flow rate measurement in ventricular assist devices (VADs) is undesirable due to the complexity and potential for thrombosis associated with additional components like flow rate sensors, and estimated flow rates based on electrical power consumption may not be sufficiently accurate in certain operational regimes.
Innovation Solution
A blood circulation assist system that estimates flow rate by determining an impeller position parameter, including rotational speed and transverse position, to provide more accurate measurements, using a controller to adjust drive current and minimize power consumption, and employing sensors to monitor magnetic flux levels for impeller position within the blood flow channel.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a flow rate sensor is used to directly measure blood flow rate, then measurement precision is improved, but device complexity increases and thrombosis risk increases
Solution Approach 1:
The patent replaces mechanical flow rate sensors with a magnetic levitation system that uses magnetic fields to both levitate the impeller and measure flow rate. The motor stator generates magnetic fields that interact with the impeller, eliminating the need for separate mechanical sensors and reducing device complexity while maintaining measurement capability.
Solution Approach 2:
The motor stator serves multiple functions: it levitates the impeller magnetically, drives the impeller rotation, and simultaneously measures the blood flow rate by monitoring the interaction between magnetic fields and the impeller. This multi-functionality reduces the number of components needed while improving measurement precision.
2Measurement precision
If a flow rate sensor is used to directly measure blood flow rate, then measurement precision is improved, but the risk of thrombosis increases
Solution Approach 1:
The patent replaces mechanical flow rate sensors that directly contact blood with a magnetic field-based measurement system. The motor stator measures flow rate through magnetic interactions with the impeller without requiring additional sensors in direct contact with blood, thereby reducing thrombosis risk while maintaining measurement precision.
3Device complexity
If estimated flow rate based on electrical power consumption is used, then device complexity is reduced, but measurement precision deteriorates in certain operational regimes
Solution Approach 1:
The patent implements a feedback mechanism where the motor stator continuously monitors the interaction between magnetic fields and the impeller to directly measure flow rate. This real-time feedback provides accurate flow rate data across all operational regimes, eliminating the inaccuracies associated with power consumption-based estimation methods.
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 approach allows for more accurate estimation of blood flow rate in VADs, reducing the need for additional sensors and minimizing power consumption, while avoiding the risks of thrombosis, and improving the reliability of circulatory support in heart failure patients.
Implementation Method 1
The motor stator is operable to magnetically levitate the impeller within the blood flow channel transverse to the impeller axis of rotation
Implementation Method 2
a motor stator operable to magnetically rotate the impeller
Data Source
AI summary
Methods of operating a blood pump having a magnetically levitated impeller. A method of operating a blood pump includes controlling supply of drive currents to drive coils of the blood pump to magnetically rotate an impeller around an impeller axis of rotation within a blood flow channel of a blood pump. Supply of a bearing current to a levitation coil of the blood pump is controlled to magnetically levitate the impeller in a direction transverse to the impeller axis of rotation so as to minimize power consumption of the blood pump during operation of the blood pump.