A standardized system for describing flow/pressure relationships in vascular access devices

Area of Science:

• Biomedical Engineering
• Fluid Dynamics
• Medical Device Design

Background:

• Traditional catheter characterization relies solely on physical dimensions (length, external diameter).
• This limited approach fails to capture crucial flow-pressure dynamics essential for device performance.
• A standardized method for quantifying hydrodynamic performance is needed across various medical devices.

Purpose of the Study:

• To develop a novel system for characterizing the hydrodynamic performance of catheters and similar medical devices.
• To introduce a single, dimensionless number (M) that represents flow-pressure characteristics.
• To enable accurate prediction of fluid flow behavior for diverse medical applications.

Main Methods:

• Developed a system for determining the hydrodynamic performance number (M) based on Reynolds number-friction factor correlations.
• Constructed an alignment chart for calculating M for regular catheters based on diameter and length.
• Validated M determination through in-vitro experiments measuring pressure drop at various flow rates for devices with complex geometries (tapers, side holes).

Main Results:

• A single number, M, effectively characterizes the flow-pressure relationship for catheters.
• The alignment chart provides a simplified method for determining M for standard catheters.
• In-vitro measurements allow for accurate M determination for complex catheter designs, applicable to blood flow (Hct = 0.41).

Conclusions:

• The developed system provides a universal metric (M) for assessing the hydrodynamic performance of various medical devices.
• This single-number characterization simplifies the comparison and selection of catheters, needles, tubing, and grafts.
• The M number offers a valuable tool for optimizing fluid dynamics in medical device engineering and clinical applications.