Ventricular Assist Pump Speed Modulation for Artificial Pulse
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Solution Overview
Problem
Existing ventricular assist devices (VADs) do not effectively mimic the natural physiologic pulse of the heart, leading to potential physiologic, metabolic, and vasomotor changes, and may increase the risk of blood stasis and maladies related to reduced pulsatility.
Innovation Solution
A continuous flow blood pump is operated with a modulated motor speed in a repeating cycle, mimicking the rate of pressure change of a natural physiologic pulse by alternating between multiple speed levels, including a sequence of increasing and decreasing speeds to generate pulsatile blood flow.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a continuous flow blood pump is operated at constant speed, then the pump provides stable blood flow, but it fails to mimic the natural physiologic pulse leading to blood stasis and metabolic changes
Solution Approach 1:
The blood pump operates in a repeating cycle with multiple speed levels, transitioning between high speed (first level), intermediate speed (second level), and low speed (third level). This periodic modulation creates pulsatile blood flow that mimics natural physiologic pulse patterns, preventing blood stasis and associated metabolic changes while maintaining overall flow stability
Solution Approach 2:
The pump speed is dynamically adjusted through controlled transitions between different operating levels. The system modulates motor speed rather than maintaining a fixed constant, allowing the pump to adapt its flow characteristics cyclically to replicate natural heart pulse dynamics while preserving reliable blood circulation
2Adaptability or versatility
If the blood pump speed is modulated in a repeating cycle with multiple speed levels, then pulsatile blood flow is generated mimicking natural pulse, but the control system complexity increases
Solution Approach 1:
The control system implements a predetermined repeating cycle with defined speed transitions between first, second, and third levels. This periodic control pattern simplifies the complexity by using a fixed, predictable sequence rather than requiring complex real-time adjustments, while still achieving versatile pulsatile flow generation that mimics natural pulse
Solution Approach 2:
The system controls pump speed by changing the motor operating parameter between discrete speed levels. This parameter modulation approach allows pulsatile flow generation through simple speed transitions rather than complex control algorithms, reducing system complexity while maintaining adaptability to generate physiologic pulse patterns
Data Source
AI summary
A ventricular assist device includes a housing, a rotor, a stator assembly, control electronics, and a percutaneous cable. The housing includes a dividing wall that delineates an inner volume. The rotor includes one or more permanent magnets and centrifugal impeller blades. The rotor and the inner volume are sized for complete magnetic levitation of the rotor within the inner volume so that blood flows through a secondary blood flow path between the rotor and the dividing wall. The stator assembly includes drive coils and levitation coils arranged radially relative to the rotor. The drive coils are operable to drive rotation of the rotor. The levitation coils are operable to electromagnetically levitate the rotor to control a radial position of the rotor within the inner volume. The control electronics are disposed within the housing and configured to control electrical supply to the drive coils and the levitation coils.