LaReine Yeoh1, Luke Cogar1, Mayes Barak2, Lit Yeen Tan3, Gavin Spargo1, Mr. Jonathan Burdach4
1Technology Development Group, Nanosonics Ltd., Sydney, Australia, 2Bioscience, Nanosonics Ltd., Sydney, Australia, 3Clinical Affairs, Nanosonics Ltd., Sydney, Australia, 4Medical Affairs, Nanosonics Ltd., Sydney, Australia
Biography:
Jon Burdach, PhD, is Chief Medical Affairs and Scientific Officer at Nanosonics Ltd. Dr. Burdach is responsible for the company's medical strategy, including clinical research, healthcare professional engagement, scientific communications and medical education initiatives.
Dr. Burdach received his Bachelor's degree in Biomedical Science from the University of Tasmania and his PhD in Biochemistry and Molecular Genetics from the University of New South Wales. He has worked within the medical research space for over 15 years and has served as a committee member on various standards development committees and has authored numerous scientific publications and regularly presents at international conferences.
Abstract:
Introduction
Ultraviolet-C (UV-C) light has recently been utilised for the high-level disinfection (HLD) of semi-critical medical devices. These are devices that contact non-intact skin or mucous membranes during use and represent an increased infection risk to patients. There is a lack of data demonstrating that UV-C irradiance can be uniformly applied to complex surfaces that contain grooves, notches and imperfections. This study focused on ultrasound probes as commonly used medical devices to show the distribution of irradiance on these surfaces.
Methods
An endocavity probe and surface probe were 3D modelled and an array of UV-C light-emitting diodes irradiating the probe surfaces was simulated (simulated wavelength: 275nm [peak], power output: 50mW). The simulated chamber wall material was equivalent to polished aluminium with a reflectance of 79% at 275nm. To calculate the cycle time required to achieve HLD on probe surfaces, a minimum effective dosage of 1500mJ/cm² based on published research was used.
Results
The simulated irradiance distribution showed a large difference between highest and lowest points of irradiance (max/min ratio: 14.7 for the surface probe and 12.7 for the endocavity probe). Partial shadowing effects adjacent to notches or grooves were evident. By applying the UV-C dose from the literature, cycle times of up to 24 minutes would be required to achieve HLD in the minimally irradiated areas of the probes.
Conclusion
These findings highlight the need for manufacturers of UV-C devices to demonstrate the efficacy of UV-C radiation against worst case organisms in the areas of lowest irradiance on medical devices.