Product confusion in ultrasound disinfectants is a risk to patient safety

Non-compliance in the adequate disinfection of surfaces and medical devices is a growing area of concern for infection control.

Ultrasound has long been considered an invaluable tool for both treatment and diagnosis in a number of medical fields. With time, new technologies and practices have developed that incorporate ultrasound, and units are now commonly used in a significant number of clinical areas outside of the medical imaging department. Many of these areas are busy environments that carry a greater risk of device contamination and potential for infection, including Emergency Departments, Intensive Care Units (ICUs) and Theatres. In many cases, infection control policies and practices have not developed with imaging practices. With new studies and findings published all the time showing the infection risks associated with ultrasound, it is vital that disinfection is considered as a routine part of practice.

While generally classed as a non-critical device, skin surface transducers are often visibly soiled, or contaminated with microorganisms. Even when used on intact skin, contamination from commensal organisms presents a clinical concern to immunocompromised patients. According to AS/NZS-4187, skin surface probes for general use are classed as a non-critical device that must only undergo cleaning, and/or low or intermediate level disinfection as required. Cleaning products have limited efficacy, but use of these devices on intact skin means that the risk is low. According to the Therapeutic Goods Administration (TGA) requirements, low-level disinfection provides efficacy against bacteria and some viruses, and intermediate-level disinfection against bacteria, viruses, fungi and mycobacteria.

A study by the Australasian Society of Ultrasound in Medicine (ASUM) found that 60% of trans-abdominal (TA) probes had evidence of bacterial contamination after an ultrasound examination, with low-level disinfection shown to only be partially effective^[1] in solving the problem. If these devices are subsequently used on non-intact skin, this is a significant infection control risk. While considered low-risk, these probes may be used on patients with compromised immune systems, wounds or incisions, during injections, or directly on mucosa or other semi-critical spaces. This presents a significant risk of exogenous infection. These probes should be high-level disinfected before use and should also have a rigorous day-to-day protocol for routine disinfection.

Many facilities are often unclear or confused about what products they can use on their skin surface transducer, and when and how they can be used. While many wipes are marketed for cleaning, often they have been tested and TGA-approved for cleaning of environmental surfaces only. These products are not approved for use on medical devices within Australia, even if the ultrasound Instructions for Use (IFUs) list them as compatible. As a result, facilities could unknowingly be using non-compliant products, with increased risk and liability.

Additionally, there are a number of products that have been approved for both surface disinfection and degrees of device disinfection. This could potentially lead to product confusion — products could be seen as ‘all encompassing’, and with significant likelihood of inappropriate use. Surface disinfectants should be used for surfaces and device disinfectants for devices, to ensure appropriate instructions, use and outcome.

Recently, the joint Australasian College for Infection Prevention and Control (ACIPC) and ASUM Guidelines for Disinfection of Ultrasound Transducers^[2] were released to provide guidance as to when specific products should be used depending on the circumstances. Skin surface probes often fall into different categories depending on use, and the importance of proper disinfection is highlighted.

Given the number of skin surface procedures, conventional high-level disinfection practices may be impractical or time consuming. Many conventional chemistries are dangerous to handle or can damage the delicate ultrasound transducer. Conversely, cleaning may be inadequate, and low-level disinfection only covers a limited range of microorganisms. As ultrasound becomes more mobile and widespread, disinfection should be accessible, easy to complete and effective.

Tristel has recently released its latest product specifically for ultrasounds. Tristel Duo NCU provides intermediate-level disinfection in 30 seconds, eliminating microorganisms of concern (including mycobacteria, viruses, fungi and vegetative bacteria), and is ideal for skin surface probes. In addition to the ultrasound transducer, Duo NCU can also be used on other areas of concern — for example, the transducer cord, stand, keyboard/control panel and monitor. It is the only disinfectant that treats all parts of an ultrasound unit the same.

Using Duo NCU for intermediate level disinfection every time means using a product that has been designed specifically for the ultrasound. Duo NCU eliminates the question about whether to only clean or to choose low or intermediate-level disinfection. Intermediate-level disinfection provides the assurance of the highest instrument-grade disinfection suitable for non-critical devices, in a fast, portable and easy-to-use package.

Ultrasound applications and risks have increased; Duo NCU enables Infection Control to keep up.

For more information visit www.tristel.com or get in touch:

Tristel Australia — 1300 680 898 mail-au@tristel.com

Tristel New Zealand — +64 (0) 7 5771560 info@tristel.co.nz

References

1. Westerway, SC., Basseal, JM., Brockway, A., Hyett, JA. and Carter, DA. (2016). Potential Infection Control Risks Associated with Ultrasound Equipment – A Bacterial Perspective. Ultrasound in Medicine & Biology. 43. DOI: 10.1016/j.ultrasmedbio.2016.09.004
2. ACIPC and ASUM (2017) ‘Guidelines for Reprocessing Ultrasound Transducers’ Australasian Journal of Ultrasound in Medicine, vol. 20, no. 1, pp. 30-40 [Online]. DOI: https://doi.org/10.1002/ajum.12042