Endoscopes

Endoscopes are essential accessories for investigating, diagnosing, and treating conditions affecting the digestive tract, respiratory tract, urinary tract, and genital tract.

• A tube with a rigid part and a flexible part

• A device for illuminating the area being observed (external light source and fibre optics)

• An image transmission and collection device (lens, fibre optics, eyepiece, and/or camera)

• A channel through which instruments can be inserted, for example, to perform a biopsy

• An air or water supply channel

The complexity of multi-channel endoscopes means that they have many points where dirt and contaminants can be protected from cleaning and disinfection. The persistence of dirt promotes the development of biofilms in which bacteria are more resistant to disinfection.

• The nature of the procedures for which they are used: septicity of the cavities inspected, invasive nature of the procedures (biopsy, dilation of bile ducts). Procedures are considered “semi-critical” when they do not involve tissue penetration and “critical” when they are invasive.

• The care taken in cleaning and disinfecting the device and, more generally, in its maintenance

All types of microorganisms (viruses, bacteria, fungi, parasites) may be present.

The diversity of microorganisms involved in endoscope-related infections is therefore very high. They are mainly associated with bacteria and viruses and, more exceptionally, with fungi and parasites.

Manual treatments

After use, the devices undergo eight codified cleaning, rinsing, disinfection, and drying operations. The internal channels of the device are rinsed with “standard care water” that has been microbiologically tested beforehand. Cleaning is carried out using detergents approved for this purpose by the endoscope manufacturer. Flexible multi-channel endoscopes belong to the category of instruments known as heat-sensitive instruments. They can therefore not be disinfected by autoclaving. The operation is carried out using disinfectants whose type and concentration are adjusted according to the level of sterility required. A final rinse with sterile water or bacteriologically controlled water (EBM) is followed by drying with “medical air.”

Automatic treatments

Some of the operations described above can be carried out using automatic devices known as “endoscope washer-disinfectors” or EWDs. These devices are more or less specific to the type of endoscope. They also use “bacteriologically controlled water”, which is subject to bacteriological checks.

The storage conditions for endoscopes (enclosures, storage duration) after treatment are also regulated. Specialised enclosures known as “thermosensitive endoscope storage enclosures” (ESET) are commercially available.

Bacteriological control of endoscopes

In addition to the water used in post-use treatment, the device itself is checked for bacteria on a regular or ad hoc basis, for example, following a nosocomial infection alert. This operation is carried out by injecting a “sampling solution” (ideally a sterile surfactant solution capable of neutralising any remaining disinfectant) into the endoscope by qualified personnel. Although not recommended, the analysis can be carried out on water collected from automatic endoscope washer-disinfectors (LDE). Except in special cases, bacteriological analysis is that of the total revivable aerobic mesophilic flora (count by culture), from which the absence of indicator bacteria (enterobacteria, staphylococci, pseudomonads, candida, etc.) is verified.

• Quality assurance elements in hygiene relating to the microbiological control of endoscopes and traceability in endoscopy. DGS, 2007, 55 p.

• Control of endoscopes by channel or cumulative channels according to the method of the Ministry of Health guide on endoscopy – March 2007.