Flexible Endoscopy

For flexible endoscopes, the first reprocessing step, known as bedside cleaning, takes place at point of use.

The subsequent reprocessing steps are performed in a reprocessing room located close to the point of use, or are centralized under the responsibility of the sterilization department. In all cases, reprocessing is performed by trained operators dedicated to these tasks.

Sterilization of flexible endoscopes is performed after point of use processing (bed-side cleaning), pre-cleaning, cleaning, drying, and packaging and is followed by storage in a sterile barrier system until use.

High-level disinfection of flexible endoscopes includes: point of use processing, (bed-side cleaning), pre-cleaning, cleaning, intermediate rinsing, high-level disinfection, final rinsing, drying, and storage.

Point of use reprocessing (bed-side cleaning) and pre-cleaning are manual. Cleaning, intermediate rinsing, disinfection and final rinsing are manual or automated (preferred).

The AER must be periodically self-disinfected to prevent development of biofilm in distribution circuit. Self-disinfection is preferably thermal.

Final rinsing filter must be replaced according to AER manufacturer instructions or applicable guidelines. Failure of self-disinfection and final filtering remain among the most frequent sources of endoscope contamination.

AERs are sophisticated electronic and mechanical equipments subject to intensive use. Maintenance contracts and manual back up procedure must be organized to ensure process continuity.

Maximum storage times before use or reprocessing are commonly defined by local regulations. In some countries, storage limits can be extended when endoscopes are placed in a storage cabinet that dries endoscopes, including lumens with filtered air, or confines them in conditions (e.g. vacuum) that prevent growth of germs.

Given the large variety of endoscopes, reprocessing equipment, chemicals, cleaning accessories, as well as guidelines and regulations applicable to flexible endoscopy, it is difficult to describe all reprocessing variants in detail. However, key principles can be summarized as follows:

• Point of use processing (bed side cleaning) is done immediately after use before bioburden has an opportunity to dry. The objective is to eliminate visible soils by wiping external surfaces and aspiration and flushing of lumens with large volumes of water and detergent. Operators’ hands are protected by single use gloves which are disposed of after the procedure.
• Transfer to the reprocessing room is done before remaining soil has an opportunity to dry. Soiled endoscopes are contained in a manner that prevent exposure of staff, patients, or the environment to potentially infectious organisms. An open container can suffice for transport to immediately adjacent reprocessing rooms, but fully enclosed containers or bags are required for transportation on longer distances. The container carries visible and clear indication that the flexible endoscope is contaminated.
• Leak test takes place before any immersion after removal of distal cap and valve). Leak test checks the integrity of the endoscope’s outer sheath. Leak test equipment and pressure are according to flexible endoscopes manufacturer’s instruction for reprocessing. If a leak is detected, the endoscope is sent for repair. The case or container used for transport to the maintenance workshop is agreed with the service provider and carries a visible indication that content is soiled.
• Pre-cleaning occurs within a defined time frame after use to avoid drying of soils and formation of biofilms. The endoscope is completely immersed in a detergent bath. All channels must be filled with cleaning liquid. Lumens are brushed with single use (preferred) or reusable brushes that were previously sterilized or high-level disinfected. The brushing direction depends on the endoscope type and manufacturer. External surfaces including valves, channels, connectors, and detachable parts of the endoscope are cleaned with soft cloth, sponge, or brushes. Valves are repeatedly actuated during cleaning to facilitate access to all surfaces. Brushes’ characteristics are according to flexible endoscope manufacturer instructions; in particular, those used for channels are adapted to the internal diameter for efficacy of cleaning and to avoid damage to the lumen.
• Point of use processing (bed side cleaning) is done immediately after use before bioburden has an opportunity to dry. The objective is to eliminate visible soils by wiping external surfaces and aspiration and flushing of lumens with large volumes of water and detergent. Operators’ hands are protected by single use gloves which are disposed of after the procedure.
• Transfer to the reprocessing room is done before remaining soil has an opportunity to dry. Soiled endoscopes are contained in a manner that prevent exposure of staff, patients, or the environment to potentially infectious organisms. An open container can suffice for transport to immediately adjacent reprocessing rooms, but fully enclosed containers or bags are required for transportation on longer distances. The container carries visible and clear indication that the flexible endoscope is contaminated.
• Leak test takes place before any immersion after removal of distal cap and valve). Leak test checks the integrity of the endoscope’s outer sheath. Leak test equipment and pressure are according to flexible endoscopes manufacturer’s instruction for reprocessing. If a leak is detected, the endoscope is sent for repair. The case or container used for transport to the maintenance workshop is agreed with the service provider and carries a visible indication that content is soiled.
• Pre-cleaning occurs within a defined time frame after use to avoid drying of soils and formation of biofilms. The endoscope is completely immersed in a detergent bath. All channels must be filled with cleaning liquid. Lumens are brushed with single use (preferred) or reusable brushes that were previously sterilized or high-level disinfected. The brushing direction depends on the endoscope type and manufacturer. External surfaces including valves, channels, connectors, and detachable parts of the endoscope are cleaned with soft cloth, sponge, or brushes. Valves are repeatedly actuated during cleaning to facilitate access to all surfaces. Brushes’ characteristics are according to flexible endoscope manufacturer instructions; in particular, those used for channels are adapted to the internal diameter for efficacy of cleaning and to avoid damage to the lumen.
• For Manual Cleaning the endoscope is placed in a detergent bath. Endoscope channels are flushed and the endoscope is maintained immersed according to manufacturer’s instructions. For automated cleaning, scope is installed in basin with gloves.

• Intermediate rinsing is performed with potable water at least. The objective is to eliminate detergent residues to avoid interaction with disinfection chemistries. Channel are irrigated and purged with air.

• Disinfection achieves the targeted germ inactivation objectives (sporicidal in some cases). Immersion and channel irrigation times are according to chemistry manufacturer instructions. Channels are purged. If the disinfection solution is reused, routine controls (daily or more frequently in accordance with manufacturer’s guidelines) ensure at least the minimum effective concentration (MEC) of the active ingredient. If the chemical indicator shows that the concentration is less than the MEC, the solution is discarded.
• Final rinsing eliminates disinfection chemistry residues with filtered or sterile water. Channels are flushed. Connectors are reprocessed according to manufacturer recommendations, preferably sterilized. The rinse water is discarded after each use/cycle.

• Drying eliminates rinsing water before storage. Outer surfaces and channels are flushed, preferably with medical air. In some countries there are recommendations to flush channels with with 70% to 90% ethyl or isopropyl alcohol to accelerate drying. This practice is prohibited in other regions due to the protein fixative properties of isopropyl alcohol.
• Air purge.

• Transfer to the storage zone is done in a manner that prevents contamination and damage of endoscopes. For long distance transfer, disinfected endoscopes are contained in a closed container or bag with visible indication that the content is disinfected. Transfer to an adjacent storage space or drying cabinet is performed with precaution to avoid any contact with potentially contaminated objects. Sterilized endoscopes are protected by a sterile barrier system. The packaging system is defined by risk analysis (see packaging).
• Storage rules for disinfected flexible endoscope vary according to applicable guidelines or regulation from a few hours to several days. In countries where rules do not allow overnight storage, the endoscope must be reprocessed before next use. The storage period may be prolonged by using storage cabinet.
  Critical endoscopes that were disinfected must be used immediately after reprocessing. Sterilized endoscopes are stored in specified conditions and area. Maximum storage duration is event related and defined by risk analysis (see storage). Endoscope accessories are stored with endoscopes for traceability.

The above can be illustrated as below:

1. Flexible endoscope reprocessing is performed according to manufacturer instructions and in accordance with applicable guidelines
   • Flexible endoscopes such as ureteroscopes, cystoscopes, hysteroscopes, choledoscopes are critical devices that should be sterilized. By default sporicidal disinfection with sterile water is applied.
   • Semi-critical endoscopes are high-level disinfected,
   • Flexible endoscopes used with accessories that cross the mucous membrane should be considered critical devices. Special attention is given to cleaning of complex endoscopes such as endosco ERCP, EUS and EBUS.
2. Preparation of high-level disinfection or sterilization (i.e. point of use processing, pre-cleaning, cleaning) is performed with care according to detailed standard operating procedures. Complex flexible endoscopes with multiple and long channels such as duodenoscopes deserve special attention. Cleaning and high-level disinfection are preferably performed in automated endoscope reprocessors (AER).
3. Operators are adequately trained and protected. Facilities and workstations are optimized to limit exposure to chemicals and minimize musculoskeletal impacts. Processes (manual or automated) undergo process validation.