The decision to change the way flexible endoscopes are processed—by replacing high-level disinfection with low-temperature sterilization—can generate a powerful return on investment for hospitals, by preventing the transmission of dangerous multidrug-resistant bacteria.
Careful planning, and assuring the necessary resources and training are available for hospital personnel, is critical to successfully making this switch. Lawrence F. Muscarella, president of LFM Healthcare Solutions LLC in Montgomeryville, Pennsylvania, recently investigated this kind of undertaking for Ambu and has a paradigm to help advise hospitals considering whether to sterilize a flexible endoscope.
In 2012, patient exposure to a duodenoscope first emerged as a recognized risk factor for transmitting carbapenem-resistant Enterobacteriaceae (CRE) and related multidrug-resistant organisms. In several well-documented instances, bacterial outbreaks were reported to occur despite confirmation that the duodenoscope was being cleaned and high-level disinfected correctly, according to the manufacturer’s IFUs.
In earlier years, infections linked to a contaminated duodenoscope or other type of flexible endoscope were almost always attributed to an identifiable reprocessing breach, another type of infection-control lapse or defective equipment. Examples of these breaches include faulty cleaning, inadequate high-level disinfection and improper endoscope drying prior to storage.
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Duodenoscopes—with a complex design that includes a forceps elevator mechanism that contains difficult-to-clean microscopic crevices—are used to perform endoscopic retrograde cholangiopancreatography, or ERCP, approximately 500,000 times annually in the U.S. On the heels of the outbreaks linked to duodenoscopes, reports confirmed that other types of flexible endoscopes—including bronchoscopes, gastroscopes and flexible intubation endoscopes—could infect patients with multidrug-resistant bacteria.
In addition to inadequate cleaning and disinfection, complex designs, instrument damage, improper maintenance and faulty repairs are primary risk factors for endoscopes exposing patients to CRE and related multidrug-resistant organisms. However, an accurate estimate of the true infection risk has been difficult to calculate in part due to a lack of post-endoscopic surveillance designed to monitor patients for infections.
Flexible endoscopes including less-complex intubation endoscopes—which are used to examine a patient’s larynx, trachea and vocal cords—are classified by the Centers for Disease Control and Prevention as semi-critical devices. These devices contact intact mucous membranes or non-intact skin, posing a lower risk of infection than more invasive critical devices, which enter sterile tissues or the vascular system. Biopsy forceps, surgical scalpels and orthopedic implants are examples of critical devices.
Despite their posing a lower infection risk, the FDA recommends sterilizing semi-critical devices to provide a greater margin of safety and help further prevent transmissions not only of CRE and related multidrug-resistant organisms but also of colistin-resistant bacteria whose infections can be even more difficult to treat.
When sterilizing a semi-critical device is not practical or feasible, however, the FDA recommends high-level disinfection. For completeness, non-critical devices contact intact skin (but not mucous membranes) posing a low infection risk. Examples include bedpans, stethoscopes and crutches. The CDC recommends cleaning alone, or cleaning followed by low- or intermediate-level disinfection of these devices, depending on the nature and extent of contamination.
How is this done? High-level disinfection involves completely immersing cleaned reusable instruments in a FDA-cleared liquid chemical germicide. Along with the immersion temperature, the disinfectant’s concentration and exposure time directly impact the process’s effectiveness.
Sterilizing surgical instruments, on the other hand, may be accomplished using heat, usually pressurized steam. If the heat damages an instrument, a low-temperature sporicidal technology may be used instead. The success of low-temperature sterilization depends on several factors, however, particularly the effectiveness of cleaning and that the device’s design and physical dimensions (e.g., the length of an internal channel) comply with the technology’s FDA-cleared labeling claims.
Before replacing high-level disinfection with low-temperature sterilization, Dr. Muscarella suggests that hospitals classify their inventory of flexible endoscopes into one of three general groups based primarily on published data and facility’s assessment of the device’s infection risk.