A test method to assess the contribution of fluid shear stress to the cleaning of reusable device surfaces

Abstract

Adequate cleaning of reusable medical devices is critical for preventing cross-infection among patients. For reusable medical devices, cleaning using mechanical brushes and detergent may not be sufficient to completely remove the infectious contaminants from the surfaces. This study evaluates the role of fluid flow-induced shear stress in the detachment and removal of contaminants from device surfaces. A stainless-steel test coupon, acting as a surrogate for a device surface, was coated with artificial clot of varying mass. The test coupon was exposed to fluid shear stress both with and without an enzymatic detergent. The relationship between clot removal quantity and the applied shear stress was obtained for multiple clot masses. Our results showed that fluid shear increased the effectiveness of the cleaning process. In the absence of flow, soaking the clot surface in the enzymatic detergent removed 67%, 77%, and 95% of the clot for 16 mg, 6.8 mg, and 1 mg initial masses, respectively. In the presence of fluid shear (0.3 Pa for 5 min), approximately 85%, 97%, and 99% of the clot was removed from the surface. The clot mass removed followed a linear relationship (R = 0.98) versus the applied fluid shear stress. This study showed that different cleaning processes such as fluid shear and detergent action contribute to the soil removal process. This method could be used to evaluate cleaning protocols for minimizing contaminant residue after the reprocessing of medical devices.

Advancing Regulatory Science With Computational Modeling for Medical Devices at the FDA's Office of Science and Engineering Laboratories

“…Another demonstrative example of FDA's commitment to facilitating innovation in medical devices is the collaboration between CDRH and industry through the Medical Device Innovation Consortium (MDIC) using the mechanism of a “mock submission” to demonstrate the regulatory process and evidence collection that could be submitted to FDA when using a new framework to augment clinical trials with virtual patients 32 . The mock submission approach has been a successful means to gather input from industry and FDA about new and innovative approaches for medical device evaluation ( 72 ). The MDIC, a non-profit in the U.S., was established to advance medical device regulatory science for patient benefit.…”