Pathological findings in silicone spallation in vitro studies

Area of Science:

• Biomaterials Science
• Medical Device Engineering
• Nephrology

Background:

• Silicone tubing is commonly used in medical devices, including hemodialysis machines.
• Mechanical stress during operation can lead to material degradation.
• Previous studies documented spallation in silicone tubing under high-flow conditions (e.g., cardiopulmonary bypass).

Purpose of the Study:

• To investigate the mechanical degradation and particle release (spallation) from silicone pump head tubings under simulated hemodialysis conditions.
• To quantify silicone particle release into the blood over extended periods of use.
• To compare silicone spallation at hemodialysis flow rates versus higher flow rates.

Main Methods:

• Simulated hemodialysis using silicone pump head tubings under mechanical stress.
• Scanning electron microscopy (SEM) for surface abrasion and damage assessment.
• Atomic absorption spectrometry (AAS) to measure polydimethylsiloxane (silicone) concentrations in circulated blood.

Main Results:

• SEM revealed significant internal surface abrasion on silicone tubing after 5 hours of use.
• Extensive damage, including splits and lacerations, was observed after 96 hours.
• AAS confirmed silicone spallation, with polydimethylsiloxane levels increasing proportionally to the duration of tubing use.
• This is the first report of silicone spallation occurring at hemodialysis flow rates.

Conclusions:

• Silicone pump head tubings undergo significant mechanical degradation during simulated hemodialysis.
• Spallation of silicone material occurs even at the lower flow rates characteristic of hemodialysis.
• The findings highlight a potential risk of silicone particle exposure to patients undergoing long-term hemodialysis.