Cannula Tip With Integrated Volume Sensor for Rotary Blood Pump Control: Early-Stage Development

Area of Science:

• Biomedical Engineering
• Cardiovascular Devices
• Implantable Sensors

Background:

• Automatic speed control for continuous-flow left ventricular assist devices (cf-LVADs) is hindered by the absence of direct left ventricular unloading measurements.
• Accurate real-time assessment of ventricular volume is essential for effective hemodynamic management and device optimization.

Purpose of the Study:

• To develop and evaluate an integrated conductance-based sensor for direct measurement of left ventricular volume.
• To enable the development of automatic control systems for cf-LVADs based on real-time ventricular volume data.

Main Methods:

• A novel inlet cannula tip for cf-LVADs was engineered with four integrated platinum-iridium ring electrodes for conductance sensing.
• A sinusoidal current excitation (250 μA pk-pk, 50 kHz) was applied, and voltage changes related to conductance were measured.
• The sensor's performance was validated in an acute ovine model using echocardiography for comparative ventricular dimension measurements.

Main Results:

• The conductance measurements demonstrated a strong linear correlation with echocardiography-derived ventricular dimensions across the entire range of pump support.
• The sensor accurately tracked changes in ventricular size from minimal support to conditions causing suction.
• The developed cannula tip provides a reliable method for real-time ventricular volume sensing.

Conclusions:

• The integrated conductance sensor on the cf-LVAD cannula tip successfully measures left ventricular volume in real-time.
• This technology is a critical step towards developing intelligent automatic control systems for cf-LVADs.
• Optimized pump performance and patient outcomes can be achieved by utilizing real-time ventricular volume feedback.