How to High-Level Disinfect Ultrasound Transducers, Part I

A previous blog post took you through the necessary steps for cleaning ultrasound transducers in How to Clean an Ultrasound Probe. Cleaning is a fundamental step that cannot be skipped before you disinfect the ultrasound probe. Now we'll go over the process of high-level disinfecting an ultrasound probe. Since there's a lot to cover, we've broken it up into two parts.

CLASSIFY YOUR TRANSDUCER:

Ultrasound transducers are used in almost every department of a hospital, from Radiology and Cardiology, Surgery and Emergency Department, to Physical Therapy and Burn Units.¹ It is imperative that you know the classification and proper reprocessing technique for your probes. In the cleaning blog, we introduced you to the Spaulding Classification for critical, semi-critical, and non-critical use of ultrasound probes and reprocessing.

Ultrasound probes used in sterile body cavities or in the vascular system are classified as critical devices. Critical devices require sterilization, typically performed by steam sterilization or autoclave. However, since ultrasound probes are heat-sensitive, researchers recommend that they be reprocessed by soaking in a high-level disinfectant, or hydrogen peroxide gas plasma or vaporized hydrogen peroxide.³

Transvaginal, transrectal, and transesophageal (TEE) transducers are all probes that contact mucous membranes, which classifies them as 'semi-critical' items that should be high-level disinfected between patients.²

General surface probes that are used on intact skin, such as abdomen or breast probes, are considered low risk and require low-level disinfection. An example of a low-level disinfectant would be germicidal cavi-wipes such as Super Sani Wipes, which are considered to be both a cleaner and disinfectant, all in one. However, if a biopsy is being performed, then your facility needs to perform an assessment to determine if the transducer escalates to being considered a semi-critical or critical instrument; if so, then they may require high-level disinfection or sterilization. ⁵

• If an abdominal or breast ultrasound is performed on a high-risk patient or on non-intact skin, high-level disinfection is required.

HIGH-LEVEL DISINFECTANTS:

If you determine that your probe requires high-level disinfection, then you need to choose an appropriate high-level disinfectant.

The Food and Drug Administration (FDA) has approved ortho-phthaladehyde (OPA), hydrogen peroxide, glutaraldehyde, and peracetic acid with hydrogen peroxide as high-level disinfectants. See the FDA's list of approved high-level disinfectants.

Factors to consider when choosing a high-level disinfectant:

1. Cost per cycle

The operating cost is sometimes overlooked when considering new products. Make sure to evaluate the ongoing cost of your high-level disinfection process, as some systems require a new disinfectant with each cycle. A helpful tool is a cost calculator for TEE and endocavity probes, which will give you a 5-year reprocessing cost analysis based on the number of probes processed per week.

2. Duration of time to disinfect

Soak or exposure time varies from 5 minutes to 45 minutes, depending on the type of disinfectant and process utilized.

3. Re-Use period

Most disinfectants have a re-use period, anywhere from 14 days to 28 days. Disinfectants that have a re-use period are significantly less expensive than single-use disinfectants.

4. Ventilation requirements

Automated reprocessors, such as the ASTRA High-Level Disinfection System, provide a safe workflow for clinicians and patients without requiring ventilation changes to the physical location where the reprocessing is conducted. When reprocessing probes manually, review the disinfectant solution's MSDS sheets. GUS Disinfection Soak Stations provide vapor control for high-level disinfectants, including OPA, glutaraldehyde, and hydrogen peroxide.

5. Contraindications

There may be instances in which the disinfectant is not recommended for use with a probe. Review instructions for both the high-level disinfectant and the ultrasound probe.

6. Transducer compatibility

What works well on an endoscope might not work well for an ultrasound probe or vice versa. While checking on compatibility, make sure that your probe fits inside the disinfection chamber or container.

7. Rinsing requirements

Some disinfectants require a single rinse, and some require 3 separate large volume rinses.

Important to Note:

• Use a high-level disinfectant according to either the FDA-cleared exposure time or the manufacturer directed time.
• Quaternary ammonium compounds found in commercial sprays are not considered high-level disinfectants.⁴ They are widely used for low-level disinfection.
• Probe covers are recommended as part of the infection control process, but they do not replace the need for a high-level disinfection.⁴

There are many standards and guidelines to direct how to high-level disinfect ultrasound transducers. Work with your facility's Infection Prevention department to determine how departments will accurately classify ultrasound probes and the level of reprocessing required after each procedure.

For semi-critical devices, such as TEE or endocavity ultrasound transducers, laying out a consistent, compliant high-level disinfection process for all departments to follow is essential to ensuring clinician and patient safety, minimizing contamination risk, and reducing costs.

Infection prevention shouldn't be complicated. CIVCO's ASTRA Automated Reprocessors offer enhanced capabilities, automatically logging data and providing easy-to-follow prompts that help you stay compliant with The Joint Commission standards, while also disinfecting and reprocessing up to two probes at once with your choice of reusable, industry-leading disinfectants (Revital-Ox, RESERT HL (hydrogen peroxide), CIDEX OPA, and Metricide OPA Plus). Learn more here.

To be continued...Read Part II on How to High-Level Disinfect Ultrasound Transducers

References

1. American Journal of Infection Control, Volume 46, Issue 8, August 2018, (Ultrasound probe use and reprocessing: Results from a national survey among U.S. infection preventionists) Pg 915.
2. CDC Guideline for Disinfection and Sterilization in Healthcare Facilities, 2008. Pg 19
3. Sterilization, High-Level Disinfection, and Environmental Cleaning. William A. Rutala, David J. Weber. Pg 46
4. AIUM Practice Guidelines – Ultrasonography in Reproductive Medicine. (Guidelines for Cleaning and preparing Endocavitary Ultrasound Transducers Between Patients), pg 10
5. The Joint Commission, https://www.jointcommission.org/assets/1/6/TJC_HLD_BoosterPak.pdf