Multilaboratory study of flow-induced hemolysis using the FDA benchmark nozzle model

Area of Science:

• Biomedical Engineering
• Hemodynamics
• Medical Device Safety

Background:

• Assessing medical device safety is crucial for patient well-being.
• Computational fluid dynamics (CFD) models are increasingly used to predict blood damage.
• Standardized in vitro testing is needed to validate these CFD models.

Purpose of the Study:

• To quantify device-induced hemolysis under various flow conditions.
• To compare experimental blood damage data with CFD predictions.
• To inform the FDA's initiative on medical device safety assessment.

Main Methods:

• Multilaboratory in vitro testing of a simple nozzle model.
• Recirculation of bovine blood through nozzle and control loops for 2 hours.
• Evaluation of hemolysis based on nozzle entrance geometry and flow rate.

Main Results:

• Significant differences in hemolysis were observed across tested nozzle geometries and flow rates.
• Sharp nozzle entrances resulted in the highest hemolysis (Modified Index of Hemolysis [MIHnozzle] up to 1.239 ± 0.667).
• Intralaboratory variability was high, but results were comparable between bovine and porcine blood.

Conclusions:

• Empirical data on blood damage were generated for specific nozzle models and blood parameters.
• Findings can help advance CFD models for predicting blood damage in medical devices.
• Standardized testing is essential for validating predictive models in medical device safety evaluations.