A comparison of low-level to high-level disinfection in eliminating microorganisms from ultrasound transducers used on skin: a non-inferiority randomised controlled trial.

A comparison of low-level to high-level disinfection in eliminating microorganisms from ultrasound transducers used on skin: a non-inferiority randomised controlled trial.

Nathan Peters^1,2,3, Frances Williamson^1,2, Michelle Bauer⁴, Stacey Llewellyn⁵, Peter Snelling^2,6,7, Nicole Marsh^1,2,7, Patrick Harris^4,9, Adam Stewart^4,9, Claire Rickard^1,2,7,8, ,

¹Royal Brisbane and Women’s Hospital, Brisbane, Queensland, Australia
²University of Queensland, Brisbane, Queensland, Australia
³Department of Surgery, University of Melbourne, Melbourne, Victoria, Australia
⁴UQ Centre for Clinical Research, Brisbane, Queensland, Australia
⁵Statistics Unit, QIMR Berghofer Medical Research Institute, Brisbane, Queensland, Australia
⁶Gold Coast University Hospital, Gold Coast, Queensland, Australia
⁷Griffith University, Brisbane, Queensland, Australia
⁸Herston Infectious Disease Institute, Metro North Hospital and Health Service, Brisbane, Queensland, Australia
⁹Central Microbiology, Brisbane, Queensland, Australia








Introduction
There is lack of international consensus as to whether high- or low-level disinfection (HLD or LLD) is required for ultrasound (US) transducers used during percutaneous procedures. This study aimed to compare the effectiveness of LLD to HLD for these US transducers.

Methods
Two identical linear US transducers repeatedly underwent either LLD (Clinell Universal wipes ®) or HLD (Tristel Trio wipes ®) during the study. Randomisation determined which transducer was applied to left and right forearms of each participant. Swabs taken from transducers before and after reprocessing were plated and incubated for 4-5 days, after which colony forming units (CFU) were counted and identified. The primary hypothesis was the difference in the proportion of US transducers having no CFUs remaining after LLD and HLD would be less than or equal to the non-inferiority margin of -5%.

Results
Of the 654 recruited participants 73% (n=478) had microbial growth from both left and right arm transducers before reprocessing and were included in the paired non-inferiority statistical analysis. All CFUs were eliminated in 100% (95% CI: 99.4%-100.0%) of HLD transducer samples (n=478) and 99.0% (95% CI 97.6-99.7%) of LLD transducer samples (n=473). The paired difference in the proportion of transducers having all CFUs eliminated between LLD and HLD was -1.0% (95% CI: -2.4%- -0.2%, p-value<0.001). Conclusions Disinfection with LLD is non-inferior to HLD when microorganisms from skin have contaminated the transducer. Therefore, using LLD for US transducers involved in percutaneous procedures would present no higher infection risk than HLD.

Biography

Dr Nathan Peters is a senior staff specialist Anaesthetist working across a broad subspecialty mix in Brisbane, south east Queensland. He has a strong interest in exploring the benefits that point of care ultrasound (POCUS) can bring to patients. He is particularly active in developing and delivering education in the area of POCUS and has received awards for his excellence in this area.