Blood Pump Flow Control via Pressure Sensors
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Solution Overview
Problem
Blood pumps implanted in the body require precise control of motor speed to ensure adequate blood flow without causing ventricular collapse or suction, and existing monitoring methods are inadequate for pulsatile heart function, making it difficult to manage patient care and pump operation effectively.
Innovation Solution
Incorporating sensors on the inflow and outflow conduits to measure blood pressure and flow, allowing for continuous or periodic monitoring and adjustment of pump speed based on left ventricular or arterial pressure, using the formula Flow=(pump outlet pressure−pump inlet pressure)×C to calculate blood flow and determine motor speed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the pump speed is increased to provide adequate blood flow, then the blood flow is improved, but the ventricle may collapse due to suction
Solution Approach 1:
The patent applies feedback by using sensors to continuously monitor left ventricular pressure and arterial pressure, then feeding this information back to the controller to automatically adjust pump speed. The controller increases pump speed when blood flow is insufficient and decreases it when pressure indicates risk of ventricular collapse, resolving the contradiction between maximizing blood flow and preventing ventricular collapse through closed-loop control.
Solution Approach 2:
The patent implements dynamics by making the pump speed variable rather than fixed. The controller dynamically adjusts the motor speed based on real-time pressure measurements from sensors, allowing the pump to adapt its performance characteristics to match the patient's physiological needs and avoid both insufficient flow and ventricular collapse.
2Object-affected harmful factors
If the pump speed is decreased to prevent ventricular collapse, then the ventricle is protected, but the blood flow becomes insufficient
Solution Approach 1:
The feedback mechanism continuously monitors pressure parameters and automatically adjusts pump speed to maintain optimal blood flow while preventing ventricular collapse. The system responds to pressure changes in real-time, increasing flow when needed and protecting the ventricle when pressure indicates risk, thus resolving the contradiction between blood flow and ventricular protection.
Solution Approach 2:
The patent changes the operational parameters of the pump by dynamically adjusting motor speed based on measured pressure parameters. The controller modifies pump characteristics in response to real-time data from sensors, optimizing the balance between blood flow delivery and ventricular protection through parameter modulation.
3Device complexity
If standard blood pressure monitoring devices are used, then the equipment is simple, but the devices become useless when pulsatile heart function is absent
Solution Approach 1:
The patent introduces pressure sensors in the inflow and outflow conduits as intermediaries to measure blood pressure directly at the pump interfaces. These sensors serve as mediators that provide reliable pressure data even when the heart lacks pulsatile function, replacing the need for traditional arterial line monitoring and enabling continuous measurement throughout the pump cycle.
Solution Approach 2:
The patent substitutes traditional mechanical blood pressure monitoring methods with electronic pressure sensors integrated into the pump system. This replacement enables continuous, non-invasive pressure measurement that works reliably whether the heart is pulsating or not, maintaining measurement capability across different physiological states.
4Measurement precision
If pressure sensors are added to monitor blood pressure, then the measurement accuracy is improved, but the device complexity increases
Solution Approach 1:
The patent achieves multi-functionality by using the same pressure sensors to serve multiple purposes: monitoring left ventricular pressure, monitoring arterial pressure, and providing feedback for pump speed control. This universal use of sensors across different functions justifies the added complexity by delivering multiple measurement and control capabilities from a single integrated system.
Solution Approach 2:
The patent merges the pressure sensing function with the pump control system by integrating sensors into the conduits and connecting them directly to the controller. This consolidation combines measurement and control functions into a unified system, reducing overall system complexity compared to separate monitoring and control systems.
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 enables precise control of blood flow, prevents ventricular collapse, facilitates weaning from the pump, and maintains arterial pressure stability, improving patient management and pump operation by providing accurate and continuous blood flow measurements.
Implementation Method 1
the inflow conduit comprises a first sensor located to detect an inflow conduit pressure that is substantially the same as left ventricular pressure
Implementation Method 2
the outflow conduit comprises a second sensor located to detect an outflow conduit pressure that is substantially the same as arterial pressure
Implementation Method 3
The blood flow calculation can be based on the left ventricular pressure and the arterial pressure, based on pressure changes within the blood pump, or based on motor speed and the pressure drop across the pump
Implementation Method 4
Flow=(pump outlet pressure−pump inlet pressure)×C, where C=an empirically derived constant describing the pump geometry, surface conditions, and viscosity
Data Source
AI summary
Materials and methods related to blood pump systems are described. These can be used in patients to, for example, monitor arterial pressure, measure blood flow, maintain left ventricular pressure within a particular range, avoid left ventricular collapse, prevent fusion of the aortic valve in a subject having a blood pump, and provide a means to wean a patient from a blood pump.