Over the past decade, there has been a dramatic increase in the adoption of point-of-care (POC) ultrasound to improve patient care across a wide variety of medical specialties, including cardiology, emergency medicine, obstetrics and gynecology, orthopedics, vascular access, and more. But the rapid dissemination of POC ultrasound among new medical specialties, combined with conflicting guidance from clinical organizations, has led to widespread confusion about the infection control practices appropriate for POC ultrasound equipment.
In this blog post, we examine the rise of POC ultrasound, the controversy and confusion surrounding transducer disinfection practices, and the details behind a 2021 Intersocietal Position Statement that provides some much-needed clarity on the topic.
Advanced ultrasound visualization has proven to be a valuable tool for locating veins and guiding needles, catheters, and other devices during percutaneous procedures. The insertion of a peripheral IV catheter is the most commonly performed invasive medical procedure among hospitalized patients. Ultrasound guidance enables successful peripheral IV placement while reducing the number of failed insertion attempts and preserving vessel health.
“The use of ultrasound technology for the placement of vascular access devices has improved the overall patient experience. All efforts should be made to protect patient safety while maintaining—or even increasing—access to this valuable technology,” says Nancy Moureau, RN, PhD, CRNI, CPUI, VA-BC, a vascular access expert and CEO of PICC Excellence (Hartwell, GA), a vascular access education firm.
According to Arun Nagdev, MD, director of emergency ultrasound at Alameda Health System (Oakland), POC ultrasound has been practice-changing for the care of trauma and critically ill patients in the emergency department. “Ultrasound is a rapid, reliable tool that improves patient care by increasing diagnostic accuracy and increases the safety of lifesaving procedures such as central line placement,” he says.
Concern over Transducer Disinfection
As reliance on ultrasound guidance for percutaneous procedures has increased, so have concerns over the potential for transmission of pathogenic microorganisms via ultrasound transducers. To promote patient safety, a number of health professional organizations published guidelines that established infection control practices for percutaneous procedures and for the cleaning and disinfection of transducers between procedures.
While the published guidelines agreed that contaminations transmitted via ultrasound transducers or coupling gels might equally pose a risk of patient infection, their recommendations regarding the level of disinfection appropriate for transducers varied widely.
Central to the debate over disinfection practices is a mistaken understanding of the Spaulding Classification System for reprocessing medical devices when applying its recommendations to devices used in percutaneous procedures, explains Oliver Kripfgans, PhD, a medical ultrasound physicist and research associate professor at the University of Michigan. Published in 1957, the Spaulding system includes recommendations about the levels of cleaning, disinfection, and sterilization required for healthcare equipment. The Spaulding system is the foundation of FDA policy on the cleaning and disinfection of medical devices.
By misclassifying percutaneous procedures as ‘semicritical’ according to the Spaulding system, some organizations concluded that transducers must be processed using high-level disinfection (HLD) techniques, which typically involve placing transducers in an apparatus that exposes them to specialized disinfecting chemicals such as glutaraldehyde or a mist of hydrogen peroxide. Because of practitioner concerns about the transmissibility of pathogens via ultrasound procedures, many hospitals and infection control staff acceded to such recommendations—especially during the height of the COVID-19 pandemic—hoping that HLD would provide an extra margin of safety.
Meanwhile, citing a lack of evidence for the necessity of performing HLD—which can be both costly and time-consuming—a number of other organizations issued guidelines maintaining that adequate protection can be provided by using a disposable transducer cover or barrier during the procedure, followed by cleaning and low-level disinfection (LLD). Performed both before and after percutaneous procedures, LLD involves wiping indicated surfaces and equipment thoroughly with standard disinfectants having a documented microbial kill rate of at least 99%.
“There was great concern that we were actually harming patients by requiring high-level disinfection because it significantly limited the availability of our ultrasound transducers,” says Kripfgans, who spearheaded a taskforce convened by the American Institute of Ultrasound in Medicine (AIUM) to consider the evidence and practices associated with transducer disinfection for these types of procedures.
“We wanted to ensure that ultrasound remained both safe and available,” he adds.
Intersocietal Taskforce Supports Low-Level Disinfection
The taskforce evaluated the peer-reviewed literature and concluded that there was effectively no pertinent evidence supporting a requirement to perform HLD between percutaneous procedures.
At the beginning of 2021, the taskforce published an Intersocietal Position Statement endorsing the use of LLD effective against bloodborne pathogens for the cleaning and disinfection of transducers used in percutaneous procedures. The statement has now gained the support of 22 health professional organizations representing more than 800,000 physicians, nurses, infection control specialists, and other health professionals.
“We hope that having the support of so many organizations will encourage the widespread adoption of appropriate disinfection practices in clinical and professional settings, which will bring significant benefits to patients,” says Kripfgans.
“The last thing we want to do is make it harder for clinicians to do the right thing,” says Nagdev. “Imposing requirements for performing HLD between percutaneous procedures would significantly limit our ability to use POC ultrasound in the emergency department.
“Our goal is to improve practice and ensure safety so that ultrasound technology is available for all patients,” he adds.
Position Statement Highlights
LLD is adequate for percutaneous procedures, especially when transducer covers are used. Evidence shows that rare cases of infection are typically linked to the use of nonsterile or contaminated coupling gels, failure to use a transducer cover, or improper cleaning—but not to the use of LLD techniques.
Transducer covers for transcutaneous procedures are meant to protect the sterility of the procedure, not to make the transducer sterile. Just as a surgeon’s hands are not sterilized prior to glove application, a transducer need not be sterilized. A cover provides adequate separation of the transducer from the procedure, as gloves do for the surgeon’s hands.
Requiring HLD for percutaneous procedures is “not evidence based” and will increase “the possibility of safety events if percutaneous procedures are performed without ultrasound guidance.” The Spaulding system classifies percutaneous procedures such as peripheral IV insertion as noncritical, and therefore requiring only LLD between uses. For semicritical and critical procedures, it may be appropriate to use HLD that involves agents or disinfecting processes designed to sterilize the surface of the transducer. However, these substances and processes take considerable time, may damage the transducer, and represent significantly higher processing costs.
Intersocietal Position Statement Signatories (May 2022)
American Academy of Emergency Medicine (AAEM) 1
American Association of Neuromuscular and Electrodiagnostic Medicine (AANEM)
American College of Emergency Physicians (ACEP)
American College of Osteopathic Obstetricians and Gynecologists (ACOOG)
American College of Radiology (ACR)
American Medical Society for Sports Medicine (AMSSM) 2
American Institute of Ultrasound in Medicine (AIUM)
American Registry for Diagnostic Medical Sonography (ARDMS)
American Registry of Radiologic Technologists (ARRT)
American Society of Anesthesiologists (ASA) 3
Association for Professionals in Infection Control and Epidemiology (APIC)
Association for Vascular Access (AVA)
Emergency Nurses Association (ENA)
Infusion Nurses Society (INS)
International Society of Ultrasound in Obstetrics and Gynecology (ISUOG)
Point-of-Care Ultrasound (POCUS) Certification Academy
Society for Healthcare Epidemiology of America (SHEA)
Society for Maternal-Fetal Medicine (SMFM)
Society of Academic Emergency Medicine (SAEM)
Society of Breast Imaging (SBI)
Society of Hospital Medicine (SHM)
Society of Radiologists in Ultrasound (SRU)
1. Independently, the Emergency Ultrasound Section of the American Academy of Emergency Medicine (EUS-AAEM) has also endorsed the position statement.
2. The AMSSM board has voted to Affirm for Value the position statement.
3. The ASA Council has approved support with the following notation: “Since the document has neither been presented to nor approved by either the ASA Board of Directors or House of Delegates, it is not an official or approved statement or policy of the society. Variances from the recommendations contained in the document may be acceptable based on the judgment of the responsible anesthesiologist.”