While ultrasound is regarded as a safe imaging modality, it presents infection control risks if not managed properly. Studies show that many facilities overlook the need to disinfect probes between patients. For instance, a study by the European Society of Radiology found that 29% of respondents did not disinfect ultrasound probes after each patient.

While many healthcare facilities view patient safety as a pressing concern, some may not realize the danger posed by ultrasound imaging. Since ultrasound does not expose patients to radiation, it has a reputation of safety and rightfully so. However, clinicians using ultrasound for their exams or procedures should be aware of the infection control threat it poses to their patients.

The infection control concerns surrounding ultrasound are the primary reason behind a variety of infection prevention guidelines which have been issued in recent years. The European Society of Radiology conducted a survey of its members and asked them a variety of questions regarding ultrasound infection control practices. One key finding of the study was frightening: 29% of respondents stated they did not disinfect the ultrasound probe after each patient.

It cannot be understated that ultrasound probes can very well be a vector of infection. The medical imaging community has witnessed the exponential growth of ultrasound in recent decades. While the general public may still associate the modality with prenatal checkups, gone are the days when ultrasound was primarily used by sonographers on pregnant women.

Ultrasound is now used widely across a variety of clinical areas, including urology, cardiology, and radiology. Physicians have found that the mobility and ease of use offered by the modality, especially point-of-care ultrasound, make it an ideal choice when taking the patient to the imaging suite is not the most suitable option. Ultrasound isn’t just present for exams either: the modality can now be found in interventional settings as well.

Moreover, ultrasound has now seen extensive use in emergency medicine and in the intensive care unit (ICU). During the COVID-19 pandemic, point-of-care ultrasound was a top pick for physicians examining and treating suspected or confirmed COVID-19 patients. The ability to bring imaging into the patient’s room minimized the risk of infecting patients outside of the COVID-19 ward. However, its use in such a high-risk environment also signified new infection control threats.

With all this discussion surrounding ultrasound infection control, it is easy to lose sight of the best practices. Using ultrasound probe covers (sterile or non-sterile), the right kind of gel, and the appropriate disinfectant can reduce the risk of pathogenic transmission. But does using an ultrasound probe cover substitute disinfection? The short answer is no.

Ultrasound users should use the Spaulding classification to determine the appropriate level of disinfection and which probe cover should be employed. The Spaulding classification consists of three designations: critical, semi-critical, and non-critical. Each designation carries with it a recommended level of disinfection which practitioners should adhere too.

Endocavity ultrasound procedures may be categorized as semi-critical or critical depending on the nature of the procedure. The ultrasound can be considered semi-critical when it comes into contact with intact nonsterile mucosa or non-intact skin. On the other hand, critical is defined as when the ultrasound comes into contact with a sterile body cavity or tissue including the vasculature.

Thus, semi-critical encompasses transvaginal, transrectal, and transesophagael ultrasounds and any surface ultrasound which involves broken skin. Critical includes the use of probes in surgery, biopsies, punctures and drainages, vascular ablation, transvaginal oocyte retrieval, needle guidance, and venous catheter placement.

Upon establishing where your ultrasound-guided procedure falls under the Spaulding classification, clinicians should proceed to disinfect and protect the probe accordingly.

While sterilization is recommended for critical procedures, ultrasound probes cannot undergo sterilization due to the design of the device. As a result, be sure to use a high-level disinfectant (HLD) on the probe as this is the minimum level of disinfection for critical devices. It is also recommended that critical ultrasound probes be protected with a sterile ultrasound probe cover; however, it is not a requirement as non-sterile covers may also be used. Not only does using a probe cover prevent blood or other bodily fluids from contaminating the device, but it also preserves the sterile field and increases patient safety by creating a physical barrier between the device and the patient.

For semi-critical procedures, clinicians must perform high-level disinfection on the ultrasound probe. According to the Spaulding classification, HLD is the minimum requirement for reprocessing a semi-critical probe. Practitioners should note that HLD is able to kill all microorganisms except for bacterial spores. Endocavity ultrasound probes should also be protected with a cover, so as to prevent any contaminants from getting on the device. Common HLDs are glutaraldehyde, ortho-phthalaldehyde, and hydrogen peroxide.

Discover more about the Spaulding classification in ultrasound procedures.