Becker's Clinical Quality & Infection Control

14 Executive Briefing 2 EXECUTIVE BRIEFING SPONSORED BY Know the risks: ultrasound and healthcare-associated infections U ltrasound is one of the most common procedures in the United States, with more than 140 million ultrasound procedures performed every year. 1 These procedures are highly variable, spanning many areas of medicine and involving different techniques, clinical environments or patient characteristics. Given this variability, appropriate infection control is essential to lower the risk of infection transmission. In 2020, drug-resistant pathogens caused a 15% increase in healthcare-associated infections (HAIs) in the United States and a similar increase in patient deaths. 2 It is now estimated that 1 in 31 U.S. hospital patients has at least one HAI. 3 Proper reprocessing of medical devices, including ultrasound probes, is one of the key strategies required to break the chain of infection transmission and protect patients. Ultrasound probes can be contaminated after patient use Ultrasound probes contact a variety of hazards during use, leading to microbial contamination even with the use of a sheath. Over 90% of transvaginal ultrasound probes can be contaminated with bacteria after use. 4,5 Studies show that even after low-level disinfection with manual wipes and sprays, probes can be contaminated with viruses and bacteria, including pathogens that cause sexually transmitted infections like human papillomavirus and Chlamydia trachomatis. 4,6,7 A study of ultrasound probes in emergency and ICU settings found that almost 50% were contaminated with pathogens, including Staphylococcus and Enterococcus bacteria. 8 A landmark epidemiological study by the health authority in Scotland reported an increased risk of infection in the 30 days following an endocavitary ultrasound scan, where low-level disinfection was the practiced standard of care. 9 The study followed almost 1 million patient journeys retrospectively through linked national patient datasets between 2010 and 2016. The Scottish government has mandated high level disinfection (HLD) for semi-critical probes including endocavitary probes since 2016. 10 Standard precautions dictate that every patient must be assumed to be infectious to help break the chain of infection transmission. In medical device disinfection, this means applying the Spaulding classification to the probe before use on a patient (Figure 1). 11 Spaulding forms the basis of National standards and Federal guidelines on medical device reprocessing. 12-14 Figure 1. The Spaulding classification divides infection transmission risk based on the type of patient tissue the device will contact during use, which determines the level of disinfection. 11-14 If sterilization of critical ultrasound probes is not possible, they can minimally undergo HLD and be used with a sterile sheath. 12 Not all ultrasound procedures carry the same risk Ultrasound is used in a diverse range of procedures with different levels of infection risk. For example, there are more than 140 ultrasound-guided percutaneous procedures (involving needle puncture of the skin), spanning at least 8 types of procedural category (Table 1). The wide variation in ultrasound-guided percutaneous procedures leads to variation in the patient sites contacted during use, as well as the risk of penetrating the sterile field. Many percutaneous procedures only involve contact between the probe and healthy, intact skin. Low-level or intermediate-level disinfection are appropriate in these cases. In other cases, there may be a risk of contact with broken skin during the procedure, meaning the device is semi-critical and requires HLD. Other times, the probe may break the sterile field or directly contact sterile tissue, such as the puncture site or adjacent sterile devices. In these scenarios, the device is critical and requires sterilization or, if sterilization is not possible, HLD. A notable example is biopsies, which are defined by the FDA as semi-critical or critical in nature, minimally requiring HLD. 13 Specialty group Number of procedures Nerve block 35 Aspiration 27 Biopsy 18 Drainage 15 Vascular Access 9 Injection 9 Intraoperative 8 Ablation 6 Other 13 Total 140 Table 1. A selection of ultrasound-guided percutaneous procedures, collated from a review of published literature. The procedures can be broadly grouped into 8 different categories.

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