Stiffness of central venous catheters

Area of Science:

• Biomedical Engineering
• Materials Science
• Vascular Surgery

Background:

• Thrombogenesis is a significant complication of central venous cannulation.
• Catheter stiffness is hypothesized to be a key factor, but data are lacking.

Purpose of the Study:

• To develop a method for measuring central venous catheter stiffness.
• To quantify the stiffness of various catheter materials.
• To correlate catheter stiffness with thrombus formation.

Main Methods:

• A cantilever beam method (Grass Model DA-7) was used to measure catheter tip deflection.
• Stiffness (bending stiffness, EI) was averaged from six catheter sections.
• Twenty-seven central venous catheters (silicone, polyurethane, PVC, polyethylene, Teflon) were tested.

Main Results:

• Silicone, polyurethane, and PVC catheters had bending stiffness below 16 X 10(-6) Nm2.
• Polyethylene and Teflon catheters were significantly stiffer.
• Heparinization and radioopacity did not substantially affect stiffness.
• Lower stiffness catheters (< 16 X 10(-6) Nm2) demonstrated significantly less thrombus formation.

Conclusions:

• Catheter material and design influence bending stiffness.
• Catheter stiffness is a critical factor in central venous catheter-related thrombosis.
• Softer catheters (EI < 16 X 10(-6) Nm2) are associated with reduced thrombus formation.