A sensorless, physiologic feedback control strategy to increase vascular pulsatility for rotary blood pumps

Area of Science:

• Biomedical Engineering
• Cardiovascular Engineering
• Medical Devices

Background:

• Continuous flow rotary blood pumps (RBPs) operating at constant speeds fail to meet dynamic cardiac demands.
• This limitation leads to suction, reduced vascular pulsatility, and increased adverse events in patients.

Purpose of the Study:

• To develop and evaluate a sensorless, physiologic feedback control strategy for RBPs.
• The goal is to mitigate limitations of constant speed operation by restoring vascular pulsatility and ensuring physiologic perfusion.

Main Methods:

• A sensorless algorithm using intrinsic pump speed to derive differential pump speed (ΔRPM) was developed.
• A gain-scheduled proportional-integral controller with switching setpoints (ΔRPM_high and ΔRPM_low) was implemented.
• In-silico testing simulated various conditions including rest, exercise, and pulmonary vascular resistance changes.

Main Results:

• The control algorithm successfully augmented aortic pressure pulsatility (>35 mmHg at rest, ~30 mmHg during exercise).
• Ventricular suction was avoided, and adequate cardiac output was maintained across all simulated scenarios.
• Sensorless algorithm performance closely matched sensor-based methods.

Conclusions:

• Augmenting vascular pulsatility with RBPs is feasible using a sensorless control strategy.
• This approach can minimize adverse events associated with diminished pulsatility.
• Further validation through mock circulation and animal studies is warranted.