Toxic plumes, the contents of which include viruses, aerosols, and volatile organic compounds, are produced by vaporization of tissue by electrocautery or laser surgery (Dermatol 2021;62:37-40). Inhalation carries infectious, respiratory, and cardiovascular risks. Surgical masks provide some protection, but N95 respirators are even more protective (J Hosp Infect 2006;64:278-81).
OR air should be filtered through a high-efficiency particulate air filtration (HEPA) system. An air suction/scavenging system reduces exposure to viruses and other toxic elements of the plume. Air drawn through the scavenging system should be filtered either through a HEPA filter (99.97 efficacy at 0.3 μm) or (preferably) an ultra-low penetration air filter (99.9995% efficacy at 0.12 μm).
Toxic volatile gases readily pass through HEPA or ULPA filters but can be removed with activated carbon filters. ORs should be maintained at pressures below atmospheric to ensure that the toxic fumes leave through exhaust vents and not through doors into adjacent hallways.
“If possible, all endoscopes should be sterilized. Manual disinfection is no longer recommended. All endoscopes should be completely dried externally and internally before reuse.”
The CDC defines Spaulding Classification as “a strategy for sterilization or disinfection of inanimate objects and surfaces based on the degree of risk involved in their use.” (Disinfection, sterilization, and preservation. 1968). Medical instruments are classified into critical, semi-critical, and non-critical, also referred to as high risk, medium risk, and low risk.
- Critical (high-risk) devices: These devices penetrate skin or mucous membranes or are used in sterile tissue or intravascular space. They should be sterilized.
- Semi-critical (medium-risk) devices: These devices pose a high risk of infection because they come into contact with non-intact skin or mucous membranes. Included are endoscopes that contact mucous membranes but do not penetrate them. High-level disinfection with removal of all microorganisms except some bacterial spores is recommended.
- Non-critical (low-risk) devices: These devices come into contact with intact skin but not with mucous membranes. They pose a lower risk of infection. Low-level disinfection or intermediate-level disinfection is recommended. Intermediate-level disinfection eliminates mycobacteria and a wider range of viruses.
Proper personal protective equipment should be used while reprocessing surgical equipment (Infect Dis Clin North Am 2021;35:575-607>; asamonitor.pub/3Q71HtG).
- Cleaning: Cleaning utilizes water and either detergent or an enzymatic product to remove foreign material. Cleaning is suitable for equipment and surfaces not expected to contact skin or tissue. Cleaning is also required prior to disinfection and sterilization to remove organic and inorganic materials that often contain microorganisms.
- Disinfection: Low-level disinfection with detergents and soaps destroys most bacteria, some viruses, including human immunodeficiency virus, and some fungi. Mycobacterium tuberculosis and some bacterial spores are resistant. Disinfection is appropriate for non-critical items that may come in contact with intact skin.
Intermediate-level disinfection with alcohol, aldehyde, phenol, iodophors, chlorine-based chemicals, and quaternary ammonium compounds inactivates bacteria, including Mycobacterium tuberculosis, most viruses, most fungi, and some bacterial spores. It should be used when skin contact is anticipated.
High-level disinfection with glutaraldehyde or hydrogen peroxide removes all microorganisms except some bacterial spores. It should be used when contact with mucous membranes or non-intact skin is expected.
- Sterilization: Sterilization with high heat and steam or ethylene oxide kills all microbes, including spores. Minimum exposure periods for sterilization of wrapped health care equipment are 30 minutes at 121°C (250°F) or four minutes at 132°C (270°F). Boiling is not adequate because the adequate temperature and pressure are not achieved.
- Prions: Prions cause Creutzfeldt-Jakob disease and other human-transmissible spongiform encephalopathies. They are not inactivated by conventional disinfection and sterilization procedures. Sterilization using a combination of sodium hydroxide and autoclaving is recommended (asamonitor.pub/3tm2Js5).
Failure of reprocessing due to CRE
Carbapenem-resistant Enterobacteriaceae (CRE) outbreaks have been reported in association with duodenal endoscopy, cystoscopy, and ureteroscopy (Am J Infect Control September 2016). This occurred despite following endoscope reprocessing guidelines existing at that time. The outbreaks occurred in part due to inadequate reprocessing of some components of endoscopes such as the elevator wire hinge.
Revised ANSI/AAMI Standards, March 3, 2021
In part due to CRE outbreaks, revised American National Standards Institute (ANSI)/Association for the Advancement of Medical Instrumentation (AAMI) standards (ANSI/AAMI ST91:2021) were published for flexible and semi-rigid endoscope reprocessing (asamonitor.pub/3aLuvb9). High-risk endoscopes include bronchoscopes, cystoscopes, duodenoscopes, endobronchial ultrasound endoscopes, linear ultrasound endoscopes, ureteroscopes, and others. If possible, all endoscopes should be sterilized. Manual disinfection is no longer recommended. All endoscopes should be completely dried externally and internally before reuse. Cleaning verification testing is required at each cleaning for high-risk endoscopes and at predetermined intervals for other endoscopes. The instrument/suction channel should be monitored. A 60-second leak test should be performed every day the scope is used.
Leave a Reply
You must be logged in to post a comment.