Ultrasound machine cleaning & disinfection

In recent years, ultrasound has become an essential tool when it comes to making accurate clinical decision making. But with the increase in ultrasound use, extra care must be taken to ensure that ultrasound machines and probes are effectively disinfected – especially given that recent findings have drawn a correlation between infection outbreaks and incorrect use of ultrasound equipment1.

Endoscopic procedures, transoesophageal echocardiography, transvaginal and transrectal probes (as semi-invasive procedures) require particular attention. The same applies to non-invasive probes when used for vascular access, cannulation and wound assessment, as the probes are in direct contact with broken skin.

To prevent infection transmission through ultrasound, a range of decontamination practices must be performed both before and after using the equipment on a patient.

This article will provide you with guidance on good practices and procedures for ultrasound machine cleaning and ultrasound probe disinfection as well as ways to ensure that workplace disinfection standard procedures have maximum compliance for patient and staff safety.

Protecting equipment, staff and patients: standardized ultrasound probe disinfection

Following an investigation² into the connection between ultrasound and infection outbreaks, a discrepancy was discovered in the way users approached cleaning and disinfecting of probes, especially when using sterile probe covers. This highlights the importance of following the ultrasound probe cleaning protocol as recommended by the World Health Organization (WHO) and American Institute of Ultrasound in Medicine (AIUM) for a more standardized compliant approach to cleaning and disinfection. This states that practitioners should:

Use ultrasound probe covers at all times for both interventional and endo-cavity ultrasound
Ensure the use of sterile gel in invasive and internal procedures
Use sterile probe covers
Use covers with a pore size less than 30nm to protect the transducer from most viruses
Be properly and adequately gloved during an examination, for the safety of patient and staff
Use gloves when removing the transducer cover, paying attention to prevent the transducer from coming into contact with any bodily fluid
Avoid wiping probes using dry towels as it has been proved to lead to contamination³
Decontaminate equipment after every patient.

But what’s the difference between disinfection and decontamination? Well, equipment decontamination involves disinfection but also includes several additional steps. Decontamination can be broken down into:

Cleaning
Low-level disinfection
Intermediate-level disinfection
High-level disinfection
Sterilization.

When all the steps listed above are complete, this is classed as decontamination.

What is low-level and high-level disinfection of ultrasound probes and when are they required?

Different transducers require different levels of disinfection, depending on their uses.

Low-level disinfection. External transducers are placed into contact with unbroken, clean skin. Though they require cleaning after each examination, they have been tagged “less critical” by the AIUM and, therefore, reduced to low-level disinfection.
High-level disinfection. AIUM has stated that high-level disinfection of ultrasound probes for internal use is mandatory. Alongside that, all internal ultrasound transducers should be covered with a single-use protective cover, when feasible.²

To break it down, high-level disinfection involves:

Ultraviolet light
Vaporized hydrogen peroxide
Chlorine dioxide
Manual multi-wipes
Endoscope washer-disinfectors (EWD).

For internal and interventional probes such as endo cavity transducers, high-level disinfection is also required as is antiseptic-impregnated towel in conjunction with ultraviolet light (type C).⁴

Ultrasound machine cleaning

Ultrasound machine cleaning may include the use of mild soap solution, LCD disinfectant solutions, purified water, isopropyl alcohol, wipes and lint-free cloths.

Remember, always follow the protocol to find out the specific cleaning methods and products for the relevant type of ultrasound system and transducer.

Additionally, the maintenance and cleaning of monitors, keyboards, cables and so on (even if not in direct contact with the patient) are also required on a regular basis. Surveys have shown that these equipment surfaces and accessories are often overlooked and only cleaned as little as once a week.⁶ As they contain electromechanical devices, constant exposure to dust and humidity will affect the efficacy of the ultrasound equipment, compromising their reliability and performance.

How to ensure standardized compliance in ultrasound disinfection

Whether you are safety officer, infection control manager, head of department or ICU doctor, disease infection control is of critical importance, both for the overall safety of hospital patients, as well as for medical staff.

To ensure standard decontamination practices are part of the hospital’s daily routine, recommendations are as follows:

If using Philips ultrasound machines, such as EPIQ 7, ensure that the ultrasound probe cleaning protocol is read and followed by all ultrasound users.
Ensure that disinfectants used are compatible with Philips ultrasound machines and accessories.
Put in place a tracking system checklist. The ultrasound user can follow this when decontaminating equipment; it also improves the traceability of practices.
Raise awareness of the correct decontamination procedures by encouraging healthcare professionals to undertake courses on proper ultrasound transducer disinfection.
Implement a strict training policy as well as monitoring to ensure that local US guidelines are followed systematically.
Choose ultrasound machines that are aligned with the latest cleaning technology.

Raising awareness of current best practices and guidelines will help staff and patients be protected during examinations. By following a standardized cleaning and disinfecting protocol, practitioners will ensure that diagnostic equipment is used to the best of its capacity and continues to improve patient care.

¹ Good practice in Ultrasound probe cleaning

² Guidelines for Cleaning and Preparing External- and Internal-Use Ultrasound Transducers Between Patients, Safe Handling, and Use of Ultrasound Coupling Gel

³ Good practice in Ultrasound probe cleaning

⁴ www.aium.org/accreditation/Guidelines_Cleaning_Preparing.pdf