How to prevent venous cannula orifice obstruction during extracorporeal circulation

Area of Science:

• Cardiovascular Surgery
• Biomedical Engineering
• Medical Device Design

Background:

• Venous cannula orifice obstruction is a critical issue during cardiopulmonary bypass (CPB).
• Traditional percutaneous control venous cannulas can be prone to obstruction.
• Novel cannula designs may mitigate obstruction and improve CPB efficiency.

Purpose of the Study:

• To evaluate the performance of redesigned, virtually wall-less venous cannulas.
• To compare their efficacy against traditional percutaneous control venous cannulas.
• To assess cannula performance under simulated venous drainage conditions.

Main Methods:

• A bench model simulating the vena cava with varying orifices and collapse was developed.
• Flow (Q) and pressure were measured for multiple drainage scenarios (atrial, hepatic, renal, iliac).
• Performance was tested using a centrifugal pump at different rotational speeds (RPM) and a fixed afterload.

Main Results:

• Virtually wall-less cannulas demonstrated significantly higher flow rates across all tested positions and RPMs compared to the control cannula.
• The redesigned cannulas achieved superior flow with substantially lower (less negative) suction pressures.
• Performance advantages were consistent in atrial, hepatic, renal, and iliac drainage simulations.

Conclusions:

• Redesigned, virtually wall-less venous cannulas significantly outperform traditional designs in simulated CPB scenarios.
• These novel cannulas facilitate direct venous drainage, reducing obstruction risks.
• The findings support the clinical utility of virtually wall-less cannulas for enhanced CPB performance.