Importance of transvaginal ultrasound probe high-level disinfection

The year 2020 has pushed infection prevention practices to the forefront of not only hospital meetings, but also every day household conversations. As a former Infection Preventionist, I know how tirelessly IPs work to implement protocols that prevent infections from spreading within the hospital system. IPs often oversee transvaginal ultrasound probe reprocessing and are an integral part of implementing High Level Disinfection (HLD) practices. It is essential to public health that we ensure that probes are appropriately reprocessed before use as “74% of all ‘immediate threat to life’ declarations were from improper sterilization or HLD of devices” according to The Joint Commission.¹ As our understanding of infection transmission increases, the importance of proper medical device disinfection becomes even more central to providing quality care.

The Spaulding Classification is the internationally accepted system to classify reusable medical equipment as either non-critical, semi-critical, or critical in order to guide the type of disinfection required (low-level, high-level, or sterilization) based on infection risk.² Transvaginal ultrasound probes contact mucous membranes and are thus classified as semi-critical requiring a minimum of HLD. The classification defines disinfection requirements for endocavitary probes for Federal agencies such as the CDC and FDA, and also auditors, such as CMS and the Joint Commission who are active in documenting reprocessing failures. Federal guidelines state, “the use of sheaths does not change the type of reprocessing”³ and “condoms/probe covers can fail”⁴.

There is a significant risk to public health when low-level disinfection is the standard of care for transvaginal probes. From 2010-2016 a retrospective, population-level study was conducted by UK National Health authorities in Scotland. At the time of the study, a survey found 90.5% of facilities were not performing high level disinfection.⁵ This 6-year study followed almost 1 million people and found those that had undergone an endocavitary ultrasound procedure were at greater risk of infection 30 days following the scan. Gynecology patients that had undergone transvaginal ultrasound were 41% (HR=1.41) more likely to have positive bacterial cultures and 26% (HR=1.26) more likely to be prescribed antibiotics.⁵ Subsequently, an official HLD policy for endocavitary probes was released as “…failure to comply with existing guidance on disinfection of SIUPs [semi invasive ultrasound probes] will continue to result in an unacceptable risk of harm to patients.”⁵

I am seeing impacts from COVID-19 on probe reprocessing specifically in departments with high-risk populations. Due to the risks associated with COVID-19, multiple facilities have changed their policies from requiring HLD for only transvaginal scans to all scans, including external probes regardless of Spaulding Classification. Most commonly, I am seeing this switch in practice for departments like Maternal Fetal Medicine and Obstetrics due to pregnant women being classified as a high-risk population.⁶ Newborns have tested positive shortly after birth with a severe COVID-19 illness as greater than 60% of pregnant patients that were confirmed to have COVID-19 were asymptomatic.⁷

As an IP, we are taught not just to reduce risk, but to eliminate risk wherever possible to save lives. Probe reprocessing is an often overlooked area of patient care where we are just now beginning to understand how impactful our disinfection protocols are to high-risk populations. In the future, the role of infection prevention will expand as we continue to learn from emerging public health threats.

Authored by: Crystal Treat, BS, MPH, CPH

Senior Clinical Applications Specialist

References:

1. The Joint Commission. Quick Safety. “Improperly sterilized or HLD equipment – a growing problem.” Issue 33. May 2017.
2. Spaulding EH. Chemical disinfection of medical and surgical materials. In: Lawrence C, Block SS, editors. Disinfection, sterilization, and preservation. Philadelphia (PA): Lea & Febiger; 1968. p. 517-31.
3. FDA 2019. Information for Manufacturers Seeking Marketing Clearance of Diagnostic Ultrasound Systems and Transducers.
4. CDC 2008. Guideline for disinfection and sterilization in healthcare facilities.
5. Scott D, et al. Risk of infection following semi-invasive ultrasound procedures in Scotland, 2010-2016: A retrospective cohort study using linked national datasets. 2018;26(3):168-177.
6. Coronavirus Disease 2019: Pregnancy, Breastfeeding, and Caring for Newborns. Sept 2020. https://www.cdc.gov/coronavirus/2019-ncov/need-extra-precautions/pregnancy-breastfeeding.html
7. Khoury, Rasha, et al. "Characteristics and outcomes of 241 births to women with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection at five New York City Medical Centers." Obstetrics & Gynecology. 2020;2: 273-282.