Endoscopy scopes, such as colonoscopes and gastroscopes, are flexible, lighted instruments used to examine the interior of the body’s organs and cavities. These devices are used in semi-sterile or non-sterile environments, coming into direct contact with blood, tissue, and bodily fluids. Due to this contact, a rigorous cleaning and disinfection process, known as reprocessing, prevents the transmission of healthcare-associated infections (HAIs) between patients. Reprocessing is a multi-stage procedure designed to return the complex medical device to a patient-ready state. The intricate design of endoscopes, featuring long, narrow channels for air, water, and instruments, creates significant challenges for cleaning.
Why Scope Reprocessing is Essential for Patient Safety
The complexity of endoscope design, coupled with their frequent reuse, makes them a significant challenge for infection control. If organic materials like blood and tissue are not fully removed, pathogens can quickly form a protective layer known as a biofilm inside the narrow internal channels. Biofilm shields microorganisms from the chemical disinfectants used in later stages, rendering the reprocessing effort ineffective.
Inadequate reprocessing poses a risk for the transmission of highly resistant organisms, including Clostridioides difficile and various multidrug-resistant organisms (MDROs). Pseudomonas aeruginosa is one of the most common organisms isolated from contaminated endoscopes, and outbreaks linked to contaminated scopes have occurred despite adherence to established guidelines. The U.S. Food and Drug Administration (FDA) and professional societies mandate stringent reprocessing procedures due to the high potential for cross-contamination between patients.
The channels of used endoscopes can become rougher over time, which provides a better environment for bacteria and patient soil to attach, making cleaning more difficult and contributing to biofilm formation. Non-compliance with established protocols can lead to serious adverse events, so every step of the cleaning process must be followed to ensure the physical removal of contaminants before chemical disinfection can be successful.
Immediate Care and Manual Cleaning Protocols
Reprocessing begins immediately after the procedure with bedside pre-cleaning, which prevents the drying of organic debris. Staff wipe the insertion tube and aspirate enzymatic detergent through the channels to loosen any remaining material before transporting the scope to the reprocessing area.
The next phase is thorough manual cleaning, which must be performed while the endoscope is fully submerged in a fresh enzymatic detergent solution. Enzymatic detergents contain enzymes that break down organic materials like blood, mucus, and tissue, making them easier to flush away. This mechanical scrubbing is crucial for removing the microbial burden, as disinfection cannot work if organic material remains.
Before manual cleaning, a leak test checks for damage to the exterior sheath or internal channels. A breach allows moisture to enter, promoting microbial growth, so any compromised scope must be removed from circulation. All accessible channels, including the biopsy, suction, and air/water channels, are meticulously brushed using appropriately sized, specialized brushes until no visible debris is present on the brush.
High-Level Disinfection and Rinsing
Once the scope is cleaned and rinsed to remove all detergent residue, it proceeds to High-Level Disinfection (HLD). HLD involves immersing the endoscope in a chemical solution for a specific contact time to inactivate all microorganisms, with the exception of a small number of bacterial spores. This process can be performed manually or using an Automated Endoscope Reprocessor (AER).
Common high-level disinfectants include ortho-phthalaldehyde (OPA), glutaraldehyde, and hydrogen peroxide-based solutions. The required contact time and temperature for disinfection are set by the manufacturer to ensure the chemical has sufficient time to achieve the necessary microbial kill.
A thorough rinse with sterile or filtered water is required after HLD to remove all residual chemical disinfectants from the exterior and internal channels. Failure to rinse adequately leaves chemical residue, posing a risk of chemical injury to the next patient’s mucous membranes. The concentration of the HLD solution must be monitored using a test strip to ensure it is above the Minimum Effective Concentration (MEC) before each use.
Drying, Handling, and Storage Requirements
The final stage prevents re-contamination and ensures the scope remains patient-ready. Thorough drying is essential because residual moisture, even after successful HLD, allows surviving bacteria to multiply rapidly, potentially leading to re-contamination. Drying is achieved by flushing all internal channels with forced instrument air and wiping the exterior with a soft, lint-free cloth.
After drying, the endoscope must be transferred to a dedicated storage area with handling precautions to prevent contact with non-sterile surfaces. Scopes are stored vertically in a closed, well-ventilated cabinet. These specialized storage cabinets must circulate HEPA-filtered air to further facilitate drying and prevent the accumulation of airborne contaminants.
The endoscope must hang freely without touching the bottom or sides of the cabinet or any other scope to prevent damage or moisture trapping. All removable parts, such as valves, are detached before storage to ensure all surfaces are exposed to the circulating air.