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. One person aptly coined it “Ultrasound 101.” Despite its simplicity, cleaning is a fundamental step that cannot be skipped before you disinfect. We’re now raising the bar and bringing to you Ultrasound 201 (!) to tackle the crux of the process – the actual disinfection. Since there’s a lot to cover, we’ve broken this up into two parts.
CLASSIFY YOUR TRANSDUCER:
∙Transvaginal, Transrectal and Transesophageal (TEE) probes are ‘semicritical’ items that should be high-level disinfected between patients.1
∙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, they can be reprocessed by soaking in a high-level disinfectant, or hydrogen peroxide gas plasma or vaporized hydrogen peroxide.2
∙General surface probes that are used on intact skin, such as abdomen or breast probes, are considered low risk and require a low-level disinfection. However, if a biopsy is being performed, then the risk escalates and a high-level disinfection should be performed on the probe.
- If the probe has built-in channels for the needle guide, then the channel must be thoroughly cleaned and high-level disinfected. 3
- Needle guides are ‘critical devices’ because they penetrate sterile tissue. They should be sterilized if they are not heat sensitive. 3
- If an abdominal or breast ultrasound is performed on a high-risk patient or on non-intact skin, a high-level disinfection is recommended.
HIGH LEVEL DISINFECTANTS:
If you determine that your probe requires a 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 running cost is sometimes overlooked when considering new products. Don’t let the bells and whistles overshadow the high operation costs.
2. Duration of time to disinfect
Soak or exposure time varies from 7 minutes to 45 minutes, depending on the type of disinfectant used and the 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
Review the MSDS sheets. GUS Disinfection Soak Stations provide vapor control for high level disinfectants, including OPA, glutaraldehyde, and hydrogen peroxide. Automated reprocessors, such as the ASTRA High-Level Disinfection System, provide a safe workflow for clinicians and patients.
There may be instances in which the disinfectant is not recommended for use with a 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 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.
- Wipes are used for low-level disinfection as well. They can be used on surface probes, unless biopsies are performed or patients are not at high-risk.
Probe covers are recommended as part of the infection control process, but they do not replace the need for a high-level disinfection.5
1 CDC Guideline for Disinfection and Sterilization in Healthcare Facilities, 2008. Pg 19
2 Sterilization, High-Level Disinfection, and Environmental Cleaning. William A. Rutala, David J. Weber. Pg 46
3 Journal of Diagnostic Medical Sonography, Infection Control in the Sonography Department, Tammy Tunstall, Pg 191
4,5 AIUM Practice Guidelines – Ultrasonography in Reproductive Medicine. (Guidelines for Cleaning andPreparing Endocavitary Ultrasound Transducers Between Patients), pg 10