A) CLEANING : General Principles (OMED Guidelines)
1. Key Messages
- Cleaning is the critical step in endoscope reprocessing
- Compliance with endoscope disinfection guidelines is the key factor determining endoscopy safety
- While local circumstances, training and resources may vary, high standards of disinfection must always be maintained
2. Definitions
Cleaning
The removal of blood, secretions or other debris from endoscopes and accessories.
Disinfection
The reduction or destruction of all vegetative microorganisms, mycobacteria, small or non-lipid viruses, medium-sized or lipid viruses, fungal spores, and some but not all bacterial spores to a level appropriate for safe use of endoscopes/accessories in a patient. (Note that this is a definition of high-level disinfection.)
Sterilization
The destruction of all microbial life. Validated processes are used to render a device free from all forms of viable microorganisms. (Note that this definition does not apply to prions.)
B ) Disinfection should be carried out immediately after cleaning
The principal steps in endoscope reprocessing, which should be performed as soon as possible after use, comprise:
- wiping down the insertion tube
- flushing the air/water channels
- aspirating water through the biopsy/suction channel
- dismantling detachable parts (e.g. valves)
- manual cleaning with detergent followed by rinsing
- disinfection and rinsing in an automatic reprocessor
- drying and appropriate storage
C) Cleaning is the critical step in endoscope reprocessing
The approach is the same if the presence of pathological prions (including the prions of Creutzfeld-Jakob disease) is suspected, however attention to detail is more important in this case. Accessible endoscope channels should be brushed with a disposable brush-tipped wire assembly designed for this purpose that has an appropriate length and diameter for each channel. Some guidelines recommend a double-brushing and/or double-cleaning procedure in order to remove all protein particles more efficiently.
1. Ultrasonic cleaning
Ultrasonic cleaning of reusable endoscopic accessories and components may be needed to remove material from hard-to-clean areas. The same detergent must be used for ultrasonic cleaning as for manual cleaning. The recommendations are as follows:
- a non-foaming detergent should be used which is appropriate for both manual cleaning and ultrasonic cleaning
- enzymatic detergent solutions should preferably be used
- he specific contact time recommended by the manufacturer for enzymatic detergents should be observed
- inhalation of enzyme-containing detergent aerosols and thus the risk of anaphylactic reactions should be minimized by covering the detergent container
2. Detergents
For the cleaning of endoscopes detergents with or without enzymes, and detergents containing antimicrobial substances may be used. Use of non-foaming detergents is recommended. Foaming can inhibit good fluid contact with device surfaces, and prevent a clear field of vision during the cleaning process with a risk of injury to personnel.
The detergent selected should effectively loosen organic and non-organic material so that the flushing action of the detergent fluid and subsequent rinsing water removes the unwanted material.
Detergents may contain the following substances with properties supporting the cleaning action:
- surfactants which reduce surface tension thus facilitating removal of debris
- activated H2O2 which effectively loosens debris at room temperature
- proteases which break protein debris into smaller, more soluble subunits
- amylase which catalyses the breakdown of starch
- lipase which breaks up fat-containing debris
- quaternary ammonium compounds, biguanidine, alcohols or aldehydes
Other active substances recommended for cleaning include amine compounds or glucoprotamine, peracetic acid and hydrogen peroxide.
Detergents containing aldehydes should not be used for cleaning as they denature and coagulate protein. Likewise detergents based on amine compounds or glucoprotamine in combination with glutaraldehyde for disinfection should not be used as chemical reactions may result in formation of colored residues.
Enzymatic detergents should be discarded after each use as these products are not microbicidal and will not retard microbial growth. In Europe detergents commonly used may contain antimicrobial substances which reduce the risk infection to reprocessing personnel, but they do not replace disinfection.
Enzymes generally function more effectively at temperatures above room temperature (>20-22°C) and should be used in accordance with the manufacturer’s recommendations.
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