Inconsistent instructions on ultrasound transducer disinfection procedures confuse processors
Clinicians have more and more choices for cleaning and disinfecting ultrasound transducers. Choosing the right procedure is vital for patient safety, instrument longevity and unnecessary costs. However, the requirements for which cleaning procedure to use are often confusing and inconsistent. Thus, the American Institute of Ultrasound in Medicine (AIUM) presented “Disinfection of Ultrasound Transducers Used for Percutaneous Procedures: The Intersocietal Position Statement” on February 19, 2021. This statement was created with input from members of the American College of Emergency Physicians, American Institute of Ultrasound in Medicine, Association for Professionals in Infection Control and Epidemiology, Association for Vascular Access, and Society of Healthcare Epidemiology of America. Lately, however, the confusion continues to grow due to the inconsistencies of various regulatory bodies.
For more details, Infection control today® (TIC®) spoke with Oliver D. Kripfgans, PhD, FAIUM, is an associate research professor of radiology, biomedical engineering, and applied physics at the University of Michigan.
This is the second in a series of articles based on TIC®Exclusive Krifgans interview on ultrasonic transducers.
Infection control today® (TIC®): There are many types of ultrasounds. What options do clinicians have for cleaning and disinfecting ultrasound equipment, and what options do you recommend?
Oliver D. Kripfgans, PhD, FAIUM: As coordinator of the AIUM Working Group on Cleaning and Disinfecting Ultrasound Transducers Used in Percutaneous Procedures, I naturally recommend that practitioners follow the AIUM guidelines that apply to their procedures. The cross-societal position statement on percutaneous procedures now has the support of 22 healthcare professional organizations representing over 800,000 members. It gives me goosebumps to realize how much uncertainty existed among so many individuals and organizations, and how much they appreciated having authoritative clarification on proper disinfection practices for these procedures.
But as chair of the AIUM Technical Standards Committee, I also recommend that practitioners speak with the manufacturers of their ultrasound equipment because the work of this committee has revealed that practitioners sometimes improperly clean their equipment with agents that are not compatible with their ultrasound transducers. Incompatible disinfecting agents can damage transducers and other components, leading to equipment malfunctions.
The AIUM guidelines are very specific on the steps involved in disinfecting transducers. The process begins with a simple cleaning, i.e. removing any remaining gel, tape or other debris, until the transducer appears clean to the naked eye. Next, the transducer should be inspected for any cracks, cracks or fogging that may have been caused by the use of non-manufacturer approved sanitizing agents (damaged units should, of course, be removed from service). Finally, the practitioner should use an approved process to disinfect the transducer according to its clinical application. Devices used in non-critical applications must receive low-level disinfection (LLD); devices used in semi-critical applications must receive intermediate level disinfection (ILD); and devices used in critical applications must receive high-level disinfection (HLD).
It should be noted that the intersocietal position statement does not use the term “intermediate level disinfection”. We have been advised to avoid this term as none of the relevant regulations currently provide an operational definition, leading to confusing interpretations in guidelines issued by various associations. Instead, as a self-defining equivalent, we were encouraged to use the term “LLD effective against blood-borne pathogens”. This wording makes a lot of sense and is roughly the same as the definitions used by the Centers of Disease Control and Prevention, the Food and Drug Administration, and the Environmental Protection Agency. Indeed, ILD is a method of treatment that uses disinfectants that have been shown to be effective against blood-borne pathogens.
After high-level disinfection, the next level of disinfection would be sterilization, which is almost never appropriate for ultrasonic equipment. There have been cases where novices placed a transducer in an autoclave to perform sterilization, but afterwards the transducer did not work. To my knowledge, there is only one ultrasound device, a transesophageal transducer, whose manufacturer has certified that it can be sterilized.
The level of disinfection should match the criticality of the procedure, as listed in the Spaulding classification system. Ultrasound procedures that are performed on intact skin or percutaneous procedures for placement of vascular access lines dictate the use of LLD or ILD. The ILD would be appropriate for percutaneous procedures where the transducer may be contaminated with blood or other bodily fluids. Instances where aseptic technique is not followed, or there is a failure of a transducer cover or barrier, would each call for the use of ILD.
On the other hand, intraoperative and endocavitary procedures (oral, transrectal, transvaginal) require the use of HLD. For my research on periodontal ultrasound, for example, we developed our own ultrasound probe. When disinfecting this probe before and after periodontal procedures, our residents are required to use HLD.
Practitioners who do not perform intraoperative or endocardial procedures are not prohibited from using HLD, and some experts have suggested that it may provide an “extra margin” of protection against infection. But in the case of percutaneous procedures, there is no evidence that HLD provides greater safety, and many experts have concluded that unnecessary use of HLD is generally not a prudent use of facility resources.
Very few providers are so indifferent to cost that they would take no action to reduce unnecessary spending. Procedure costs are important to providers, who would prefer to reduce these costs so that they can purchase the equipment needed to increase the throughput of their ultrasound procedure.
But in 2020, many practitioners were expressing concern that HLD performance requirements for transducers used in percutaneous procedures represented a reckless and unnecessary use of resources. Additionally, many people were concerned about facilities that did not have access to HLD technology, fearing that practitioners could continue to perform their procedures but without the benefit of ultrasound guidance.
TIC®: This‘s the origin of the intersocietal position statement; Is it correct?
OKAY: Yes, these are the types of concerns that brought together the 5 associations that became the first signatories of the position paper. All of these associations were very concerned, as their members were receiving communications either from their local infection control councils or from the Joint Commission that practitioners should use high-level disinfection even for percutaneous procedures. These instructions were controversial from the start, as individual practitioners and their professional associations agreed that the required practices made no sense.
As the leading national authority on the medical applications of ultrasound, AIUM has been asked to coordinate the efforts of a task force drawn from the signatory organizations. Our approach was to review all relevant peer-reviewed literature, assess the evidence from these publications, and develop cleaning and disinfection recommendations that would not pose an undue burden on practitioners. We also looked at recommendations from the CDC and other authoritative bodies to see what they required for cleaning and disinfecting other devices that are in the same situation as the ultrasound transducer.
Based on these reviews, in February 2021, the Task Force released the Intersociety Position Statement to clarify what cleaning and disinfection procedures are actually needed to promote safe percutaneous procedures. And we considered the question of safety in 2 ways: first, that disinfection procedures must eliminate the risk of cross-contamination; and second, that the procedures should not preclude the use of ultrasound for percutaneous procedures. Based on feedback from some providers, there was great concern that if HLD were required, some practitioners might find themselves in the position of having to perform their procedures without ultrasound guidance. Such a change would have represented a significant reduction in patient safety and a significantly increased risk to patients.