Development of a miniature motor-driven pulsatile LVAD driven by a fuzzy controller

Area of Science:

• Biomedical Engineering
• Cardiovascular Devices
• Mechanical Engineering

Background:

• Left Ventricular Assist Devices (LVADs) are crucial for managing heart failure.
• Existing LVADs face challenges related to size, weight, and efficiency.
• Development of novel LVAD designs is essential for improving patient outcomes.

Purpose of the Study:

• To develop and evaluate a small, lightweight, motor-driven pulsatile LVAD utilizing a ball screw mechanism.
• To investigate the efficacy of magnetic attractive force for active blood filling during the pump's filling phase.
• To assess the performance and efficiency of the developed LVAD through in vitro experiments.

Main Methods:

• Design and construction of a motor-driven LVAD incorporating a brushless DC motor and ball screw.
• Integration of Nd-Fe-B magnets and an iron plate to facilitate active blood filling via magnetic force.
• Implementation of a fuzzy logic position and velocity controller with independent program modules.
• In vitro evaluation using a mock circulation system to measure pump outflow, response to afterload and preload, and operating efficiency.

Main Results:

• The LVAD achieved a stroke volume of 55 ml, overall volume of 285 ml, and weight of 360 g.
• Maximum pump outflow reached 5.1 L/min at 95 bpm against 95 mmHg afterload.
• Active filling provided a pump output of 3.6 L/min at 75 bpm under 0 mmHg preload.
• Operating efficiency was measured between 8% and 10.5%.

Conclusions:

• The developed motor-driven LVAD demonstrates adequate pump outflow for cardiac assistance.
• The magnetic attractive force effectively contributes to active blood filling.
• Further advancements in software control and blood pump design are necessary to optimize performance and efficiency.