Ventricular Assist Device Pump Speed Control Algorithm
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current ventricular assist devices (VADs), particularly continuous flow LVADs, face challenges in providing adequate blood flow adaptation to changing clinical and physical activity conditions while preventing ventricular suction, which can lead to adverse events such as myocardial damage and arrhythmias, due to the lack of physiologic control mechanisms and reliance on invasive sensors prone to failure.
Innovation Solution
A novel control algorithm based on intrinsic pump speed measurements, using a gain-scheduled proportional-integral (PI) controller to maintain differential pump speed setpoints that mimic physiologic arterial pulsatility, thereby ensuring adequate perfusion and suction prevention without the need for pressure, flow, or volume sensors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If continuous flow LVAD is used to provide mechanical circulatory support, then device durability and lower thrombosis rate are improved, but ability to adapt to changing perfusion demand and prevent ventricular suction deteriorates
Solution Approach 1:
The patent implements dynamic pump speed adjustment by transitioning from fixed-speed operation to variable-speed control. The controller continuously monitors pump speed and adjusts the motor controller output to maintain a differential pump speed between systolic and diastolic phases, enabling the device to adapt to changing perfusion demands while maintaining the reliability benefits of continuous flow architecture.
Solution Approach 2:
The patent employs a feedback control mechanism where the controller monitors actual pump speed and compares it to reference differential pump speed values. Based on this feedback, the controller adjusts motor controller settings to maintain optimal differential pump speed, enabling automatic adaptation to varying physiological conditions without requiring additional sensors.
2Productivity
If pump speed is increased to meet higher perfusion demand, then blood flow to end-organs is improved, but risk of ventricular suction increases
Solution Approach 1:
The patent implements dynamic pump speed adjustment by transitioning from fixed-speed operation to variable-speed control. The controller continuously monitors pump speed and adjusts the motor controller output to maintain a differential pump speed between systolic and diastolic phases, enabling the device to adapt to changing perfusion demands while maintaining the reliability benefits of continuous flow architecture.
Solution Approach 2:
The patent applies preliminary anti-action by using suction detection algorithms that monitor pump speed morphology to predict and prevent suction events before they occur. When the controller detects patterns indicating impending suction, it proactively reduces pump speed to prevent the harmful effect, rather than waiting for suction to actually occur.
3Adaptability or versatility
If physiologic control mechanisms are added to adapt pump flow to perfusion demand, then perfusion adaptation is improved, but device complexity and cost increase
Solution Approach 1:
The patent implements self-service control by utilizing the pump's own operational parameters (motor current, speed) as feedback signals. The controller processes these intrinsic measurements to automatically adjust pump speed and maintain optimal differential pump speed, eliminating the need for external physiological sensors while achieving physiologic adaptation through the device's existing operational data.
Solution Approach 2:
The patent makes the motor controller serve multiple functions: it not only drives the pump motor but also acts as the control system that monitors pump performance and adjusts operating parameters. This multi-functionality reduces overall device complexity by eliminating separate control hardware while maintaining sophisticated physiologic adaptation capabilities.
4Measurement precision
If invasive sensors are implanted for direct pressure and flow measurement, then measurement accuracy is improved, but risk of sensor failure and thrombus formation increases
Solution Approach 1:
The patent implements self-service control by utilizing the pump's own operational parameters (motor current, speed) as feedback signals. The controller processes these intrinsic measurements to automatically adjust pump speed and maintain optimal differential pump speed, eliminating the need for external physiological sensors while achieving physiologic adaptation through the device's existing operational data.
Solution Approach 2:
The patent uses pump speed as an intermediary parameter that indirectly reflects physiological conditions. Rather than directly measuring pressure and flow with invasive sensors, the system uses easily measurable pump speed variations as a mediator to infer perfusion demand and adjust pump operation accordingly, avoiding the risks associated with direct sensor implantation.
Data Source
AI summary
Methods, systems, and computer readable media for controlling ventricular assist devices are disclosed. In some embodiments, the method includes receiving at least one reference pump speed differential associated with a pump of a ventricular assist device; determining a filtered pump speed differential associated with the pump of a ventricular assist device; and adjusting, using a feedback based controller algorithm, current to the pump based on the at least one reference pump speed differential and the filtered pump speed differential. In some embodiments, the system includes a controller implemented using the non-transitory computer readable medium, wherein the controller is configured for receiving at least one reference pump speed differential associated with a pump of a ventricular assist device; determining a filtered pump speed differential associated with the pump of a ventricular assist device; and adjusting current to the pump based on the at least one reference pump speed differential and the filtered pump speed differential.