Continuous flow total artificial heart: modeling and feedback control in a mock circulatory system

Area of Science:

• Biomedical Engineering
• Cardiovascular Engineering
• Medical Devices

Background:

• Total artificial hearts (TAH) are crucial for end-stage heart failure treatment.
• Maintaining stable blood flow and left-right balance in TAH systems is a significant challenge.
• Continuous flow pumps offer advantages but require sophisticated control mechanisms.

Purpose of the Study:

• To develop and test an in vitro physiologic flow control system for a dual continuous flow pump TAH.
• To evaluate the system's ability to maintain constant loop flow against varying outflow resistances.
• To assess the effectiveness of digital integral controllers in regulating pump speed for flow stability.

Main Methods:

• Development of a mock circulatory loop simulating cardiovascular conditions.
• Implementation of a multivariable feedback control system with two digital integral controllers.
• In vitro testing by simulating systemic and pulmonary hypertension via increased vascular resistances.
• Validation of flow regulation by measuring circuit flow response to resistance changes.

Main Results:

• The control system successfully maintained a constant circuit flow of 4 L/min under baseline conditions.
• In simulated hypertensive states, the controllers automatically adjusted pump speeds to restore flow to 4 L/min within seconds.
• The system demonstrated effective regulation of flow despite significant increases in both pulmonary and systemic vascular resistances.

Conclusions:

• The developed multivariable feedback flow control system is effective for dual continuous flow pump TAH.
• This system can provide automatic flow control and maintain left-right balance, supplementing inherent pump characteristics.
• The findings suggest potential for improved TAH performance and patient outcomes through advanced control strategies.