Medical catheters are generally inserted into the body to inject or remove fluids from a patient. Failure of these devices can result in severe patient injury. As a result, mechanical testing is a critical requirement to demonstrate device safety. In all testing applications, correct gripping is essential for obtaining accurate measurements. However, in many cases, gripping catheters with traditional side-action grips can cause stress concentration at the grip face and result in premature failure of the specimen. In addition, catheters are generally made of polymeric material that has high elongation properties at both room temperature and body temperature. Testing catheters at body temperature is challenging given that many temperature cabinets often do not have the height necessary to test catheters to failure.
In order to accurately test catheters at body temperature and avoid jaw breaks associated with side action grips, we recommend using the Instron® BioBox and pneumatic cord and yarn grips. The BioBox is advantageous as it encloses the entire test system while allowing for full crosshead travel and testing of catheters to failure. The BioBox temperature can be read into Bluehill® Universal software, allowing users to track material test data with temperature test data. The pneumatic cord and yarn grips are designed to wrap the catheter tubing before clamping, which allows for the clamping pressure to be distributed over a larger surface area. This design helps to tightly grip the material during a test, while the distribution of clamping pressure prevents jaw breaks.