High-level disinfection is a process that is used to treat medical and dental devices and instruments to completely kill viable microorganisms, except for a small number of bacterial spores and prions.
This should be followed by a cleaning process that should inhibit enough pathogens to prevent infection from being transmitted.
This process of disinfection also refers to the reprocessing of semi-critical dental instruments and medical devices that cannot be sterilized by traditional methods or are heat-sensitive.
For a better understanding of this definition, semi-critical devices refer to devices that come in contact with non-intact skin or intact mucous membranes and are not designed to penetrate tissues or other sterile areas of the human body.
High-level disinfection is regarded as the common alternative in sterilizing both critical and semi-critical medical devices that are heat tolerant and meant to be used more than once.
The Association of perioperative Registered Nurses (AORN) published new guidelines, among which are the high-level disinfection guidelines. High-level disinfecting should be done using these steps:
A number of alarming studies show that 3-7% of transvaginal ultrasound probes remain contaminated with human papilloma virus (HPV) DNA after the routine disinfection of ultrasound and medical probes and equipment.
These and other reports suggest that inactivation of all microbial pathogens or high-level disinfection may not always be properly achieved, which mostly depends on the quality of used disinfectants.
The requirements is that semi-critical devices are high-level disinfected, which includes the inactivation all microbial pathogens except large numbers of bacterial endospores.
It is important to note that the HPV disinfection researches were conducted in France, and that the routine disinfection practice in France is often only a Low Level Disinfection, typically performed with quaternary ammonium compound wipes.
Low level disinfection would not be expected to be effective against non-enveloped viruses such as HPV as they have a higher level of resistance to disinfection.
NOTE: The U.S. guidelines and standards recommend High-Level Disinfection of ultrasound probes, while this can vary internationally.
A recent study found that certain types of high-level disinfectants, based on glutaraldehyde and OPA, were ineffective against the HPV virus even after prolonged exposure.
The study concluded that oxidation-based disinfectants may be more effective at inactivating HPV. A 2015 study by Meyers confirms that hydrogen peroxide was effective in achieving a >4 log10 reduction of HPV16 and 186.
Similar results have been published for other, highly resistant non-enveloped viruses such as parvoviruses and bacteria such as aldehyderesistant bacteria.
HPV16 and 18 are classified as non-enveloped viruses. To demonstrate effectiveness against these and other viruses, the FDA requires the use of poliovirus as the marker virus.
The resistance profiles of other non-enveloped viruses (human and animal pathogens) have been investigated. These include parvoviruses, coxsackieviruses, other enteroviruses, hepatitis A virus and noroviruses.
Disinfection studies have shown that some of these viruses are distinctly more resistant than the poliovirus marker, in particular in studies with aldehyde-based disinfectants.
The most resistant to date are the parvoviruses. Parvoviruses are small (18-26 mm), non-enveloped, hydrophilic, single-stranded DNA viruses.
High-level disinfection for ultrasound probes is necessary for the sake of the patients, your healthcare team, and your reputation, which will certainly affect your bottom line.
This is because transrectal, transvaginal and transesophageal probes are considered as semi-critical items that require high-level disinfected when used between patients.
Ultrasound probes are used in the vascular system or sterile body cavities, hence the need for sterilization.
But since they are heat sensitive, they also need to be reprocessed by soaking them in high-level disinfection products.
On the other hand, general surface probes that are used on the breasts or abdomen are considered low risk, so they only need low-level disinfection, not necessarily high-level disinfection wipes.
But it’s a different story altogether if they are used in cases where biopsy is performed. The risk rises and general surface probes will need high-level disinfection solutions.
This level of disinfection is necessary for the probes’ built-in channels for the needle guide, for the needle guides that penetrate sterile tissue, and for the probes that are used on a non-intact skin or on high-risk patients.
To properly perform high-level disinfection of ultrasound probes, you also need to choose the right disinfectants.
You need to consider the time it would take to disinfect the probes, cost per cycle, reuse period, ventilation requirements, transducer compatibility, contraindications, and rinsing requirements.
When you start using chemicals such as the Resert high-level disinfection solution, make sure to follow the FDA-cleared exposure time or the time recommended by the manufacturer.
Don’t buy disinfectants with quaternary ammonium compounds because these are mostly used in low level disinfectants. While probe covers are recommended as part of your safety measure, they are not enough to prevent contamination, hence the need for high-level disinfection.
There are several challenges that are associated with high-level disinfection, starting with its numerous steps and varying requirements for each medical instrument up to its high-risk if it is not performed properly.
It is usually not well-standardized across healthcare organizations, even in the same facility that uses the same equipment. This is why it would be best to develop a policy for high-level disinfection in hospitals.
By adopting a hospital-wide policy, it means that you have to post the manufacturer guidelines for the medical equipment and disinfectant required by each and distribute it to the entire facility. This should help simplify the process and improve compliance with high-level disinfection requirements.
When it comes to disinfection of medical probes and equipment, regular disinfectants can not guarantee reliable result. That is when the risk of transmission of different viruses, fungus and bacteria is rising.
Presented high-quality medical high-level disinfectants are the best to use for sterilization of following medical probes and equipment: