Hemolytic potential of hydrodynamic cavitation.

Area of Science:

• Cardiovascular Science
• Fluid Dynamics
• Biomaterials Science

Background:

• Hemolysis, the rupture of red blood cells, is a critical concern in blood-contacting medical devices.
• Cavitation, the formation and collapse of bubbles in a liquid, is a known cause of hemolysis.
• Understanding the specific mechanisms of cavitation-induced hemolysis is crucial for device design and patient safety.

Purpose of the Study:

• To compare the hemolytic potential of discrete bubble cavitation versus attached cavitation.
• To develop an analytical model for predicting hemolysis caused by discrete bubble cavitation.
• To investigate the relationship between cavitation characteristics and hemolysis in a controlled hydrodynamic setting.

Main Methods:

• Construction of a Cavitation Susceptibility Meter (CSM) using venturi geometry for controlled cavitation generation.
• Utilizing single-pass and recirculating flow apparatus with the CSM to study discrete and attached cavitation.
• Development of an analytical model based on spherical bubble dynamics to predict hemolysis.
• Quantification of plasma-free hemoglobin (PFHb) as a measure of hemolysis.

Main Results:

• Discrete bubble cavitation did not induce a measurable increase in PFHb, aligning with the analytical model's predictions.
• Attached cavitation led to significant PFHb generation, indicating a notable hemolytic effect.
• The rate of PFHb generation during attached cavitation was inversely proportional to the cavitation number, suggesting cavity size is a key factor.

Conclusions:

• Attached cavitation is a significant source of hemolysis, whereas discrete bubble cavitation is not under the tested conditions.
• The size of the attached cavity, rather than the dynamics of discrete bubbles, appears to be the dominant factor in hemolysis.
• The findings highlight the importance of managing attached cavitation in medical devices to minimize blood damage.