Flow visualization study of a pulsating respiratory assist catheter

Area of Science:

• Biomedical Engineering
• Fluid Dynamics
• Respiratory Physiology

Background:

• Developing advanced intravenous respiratory assist devices is crucial for improving gas exchange.
• Existing devices face challenges with nonuniform flow and gas exchange rates.
• Active mixing mechanisms are being explored to enhance device efficacy.

Purpose of the Study:

• To test the hypothesis that non-symmetric balloon inflation/deflation causes nonuniform flow and gas exchange.
• To evaluate the impact of fiber bundle movement on device performance.
• To optimize the gas permeability coefficient of the respiratory assist catheter.

Main Methods:

• Utilized an in vitro flow loop with a respiratory catheter and a pulsatile balloon.
• Employed particle image velocimetry (PIV) to map fluid velocity and fiber bundle movement.
• Calculated the gas permeability coefficient using fluid and relative velocities.

Main Results:

• Balloon pulsation generated nonuniform fluid flow around the catheter.
• PIV confirmed induced fiber bundle movement.
• Relative velocity calculations showed a 17-23% variation in gas permeability, significantly more uniform than fluid velocity predictions (49-59%).

Conclusions:

• Fiber bundle movement effectively reduced fluid velocity variations within the device.
• This movement minimized nonuniformity in the gas permeability coefficient.
• The findings support the design of more efficient respiratory assist devices through controlled fiber bundle dynamics.