High-level disinfection
Disinfection of transvaginal ultrasound probes
Following concerns over infections arising from the use of ultrasound probes, there has been an increased focus on disinfection methods. A study, by the University of New South Wales, has investigated the efficacy of UVC high-level disinfection in reducing contamination.
When an ultrasound probe comes into contact with a mucous membrane or non-intact skin – such as endocavity scans, injections or interventional procedures – this is considered a semi-critical procedure. It is commonly agreed that probes used in semi-critical procedures require high-level disinfection (HLD), to prevent transmission of healthcare-associated infections (HCAIs). The importance of HLD for ultrasound probes used in semi-critical procedures was brought to the forefront following a Medical Device Alert from the MHRA – prompted by the death of a patient from hepatitis B. The incident was thought to have occurred as a result of an improperly disinfected endocavity ultrasound probe.1 In fact, there is still wide variation in practices and standards of decontamination of ultrasound probes across healthcare organisations. In some instances, probes may be given a ‘quick wipe’ between patients and a variety of different materials may be used. One study by Sartoretti et al, published in
2017, demonstrated the extent of the problem with some particularly alarming findings2
–
cultures taken from toilet seats and bus poles were shown to have a lower bacterial load in comparison to ultrasound probes. Keys et al(2015) also tested ultrasound equipment used in five EDs and five ICUs for blood and microbial contamination. They found that 61% of samples tested positive for blood contamination and 48% tested positive for microbiological contamination. Transducer leads and transducers had high blood contamination (88% and 57%, respectively) and microbiological contamination (62% and 46%, respectively). Other studies have also highlighted the increased risks associated with undergoing endocavity ultrasound.3
A combination of
training and technology are required to tackle the issue. Automated systems are available, which eliminate some of the human error and variation associated with manual wiping systems, and one such approach is the use of UVC radiation.
UVC kills cells through the accumulation
of DNA damage. The UVC light penetrates cell walls of living organisms, such as bacteria, spores, viruses, fungi and mycobacteria. It
damages the DNA structures, rendering the cell non-functional and unable to replicate. If a cell cannot reproduce it is therefore unable to spread infection. If the DNA damage is extensive, the cell will die. This is the goal of HLD.
HLD of transvaginal ultrasound probes A recent study by Professor Mark Willcox and Dr. Muhammad Yasir, at the University of New South Wales, has investigated the use of Lumicare’s UVC technology for high-level disinfection of transvaginal ultrasound probes. A transvaginal ultrasound is an internal scan
of the female reproductive organs and involves inserting a small ultrasound probe, called a transducer, into the vagina to produce detailed images of the organs in the pelvic region.4,5 Within Connect IVF (a fertility clinic based in Sydney, Australia), these probes are used to check the reasons for infertility. These probes are reusable devices that must undergo high-level disinfection before reuse with another patient.6
Technologies
for disinfecting these probes must pass international standards (EN 14561:2006 “Chemical disinfectants and antiseptics. Quantitative carrier test for the evaluation of bactericidal activity for instruments used in the medical area. Test method and requirements”). Research has already demonstrated that
the Lumicare ONE High-Level Disinfection device passes these international standards in laboratory studies. However, the latest study is significant as it has tested whether the device performs adequately in a real-life situation. The aim of the study was to examine whether
an ultraviolet C light device (Lumicare ONE High-Level Disinfection) can adequately disinfect and reduce the numbers of microbes present on the surface of ultrasound transvaginal probes after use.
Methodology The study was approved by the Human Research Ethics Committee (HREC) of the University of
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www.clinicalservicesjournal.com I November 2024
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