Sterilization is a critical aspect of any medical procedure, and this is especially true when it comes to endoscopy. Endoscopes are widely used in medical settings. However, these complex instruments require rigorous cleaning and sterilization processes to ensure that they are safe and effective for use. In this article, we will explore the various methods of sterilizing rigid endoscopes and provide some practical tips for ensuring that they are properly disinfected before use.

• What is rigid endoscope
• How to use the rigid endoscope
• How to sterilize the rigid endoscope

What is rigid endoscope

A medical rigid endoscope is a type of medical instrument used for visualizing the interior of a body cavity or organ. It is typically a thin, tube-like device with an optical system at one end and a handle at the other. The optical system consists of a lens and a fiber optic cable or a miniature camera that is used to capture and transmit images to an external monitor.
Rigid endoscopes are used in a variety of medical procedures, including ENT， arthroscopy (for examining joints), laparoscopy (for examining the abdominal cavity), and cystoscopy (for examining the urinary tract). They provide a minimally invasive way to examine and diagnose internal conditions, as well as to perform certain medical procedures.
Because of their rigidity, these endoscopes are typically used for procedures that require a straight line of sight or a fixed angle of view. They can be more difficult to use in complex or curved anatomical structures, where flexible endoscopes may be more appropriate. However, rigid endoscopes typically provide higher image quality and better visualization compared to flexible endoscopes.

How to use rigid endoscope

Prepare the patient: The patient will need to be positioned appropriately to allow access to the area being examined. Anesthesia may also be necessary for certain procedures.

Connect: Connect the endoscope with the camera’s optical coupler

Insert the endoscope: The endoscope is carefully inserted into the body through a small incision or natural opening. The endoscope may need to be guided using other instruments.

Examine the area: Once the endoscope is in place, the medical professional can use the attached camera and light source with instruments to examine or procedure the Pathological area. The images from the camera are displayed on a screen for easier viewing.

Remove the endoscope: Once the procedure is complete, the endoscope is carefully removed from the body.

How to sterilize rigid endoscope

1. Cleaning instructions for reusable endoscopes

① Rinse thoroughly with running water immediately after use to remove residual substances such as blood and mucus, and wipe dry.

② Soak the dried endoscope in multi-enzyme lotion.

③ Thoroughly clean all parts of the endoscope. The lumen should be thoroughly rinsed with a high-pressure water gun. The detachable parts must be disassembled for cleaning, and cleaned with an ultrasonic cleaner for 5 to 10 minutes.

④ Thoroughly scrub the lumen with a soft brush, and be careful not to scratch the mirror surface when scrubbing.

⑤ Description of special cleaning tools or equipment

Only use the ultrasonic cleaning machine produced by the cleaning machine manufacturer for cleaning endoscopic instruments to clean the endoscope. For the cleaning process, please refer to the instruction manual of the ultrasonic cleaning machine.

2. Cleaning of accessories

Endoscope metal accessories, such as sheaths and obturators, manipulators, connecting bridges, surgical instruments, etc., the cleaning procedures and methods are basically the same as endoscope cleaning.

① Thoroughly clean all accessories.

② Disassemble the assembly accessories, and clean the detachable parts thoroughly with clean water immediately after dismantling them. Use a small brush to carefully brush the inner surface of the surgical instruments and the joints and the channels and openings of other accessories. Hospitals with conditions can use ultrasonic waves. Shaker cleaning.

③ Soak with enzyme cleaning solution, pay attention that each hole should be filled with enzyme cleaning solution, after soaking, rinse with clean water.

④ Wash the accessories, dry and wait for disinfection.

3. Description of the special disinfection and sterilization environment that the endoscope can withstand

1) Glutaraldehyde disinfection

Endoscopes can be chemically sterilized with a high-grade sterilization solution containing 2% glutaraldehyde specifically for endoscopes. Solutions with glutaraldehyde concentrations greater than 2% should be avoided because high concentrations of glutaraldehyde may cause damage to the endoscope.

① Put the endoscope in a separate plastic container, and a plastic container should be used to avoid scratches on the endoscope and to eliminate electrolytic corrosion that occurs when different metals are immersed in the same solution. Do not immerse the endoscope with other instruments to avoid damage to the endoscope.

② Add activator solution to glutaraldehyde to activate glutaraldehyde solution. Shake well and check that the pH of the glutaraldehyde solution is between 8.2 and 8.9 to ensure that the activated glutaraldehyde solution has the best antibacterial activity. The activation and deactivation dates are marked on the container.

③ To find detailed information and instructions on the use of the glutaraldehyde disinfectant solution, please refer to the glutaraldehyde manufacturer’s instruction manual.

④ Dry the endoscope with a lint-free sterile cloth.

2) Ethylene oxide gas sterilization

① Place the endoscope in the sterile tray.

② All sterilization cycles must include a pretreatment cycle.

③ It has been verified that the following table is valid for ethylene oxide sterilization parameters.

                    Effective parameters of ethylene oxide gas sterilization

gas mixture	Ethylene oxide, chlorotetrafluoroethane
temperature	54.4℃±2.8℃（130±5℉）
Relative humidity	60 ± 20%
pressure	55.1KPa～68.9KPa（8psi～10psi）
processing time	120 minus
Ethylene oxide concentration	600 ± 30 mg/L

The gas mixture consisted of 10% ethylene oxide and 90% chlorotetrafluoroethane.

④ Ventilation of the endoscope can be done in any fume hood, maintaining the temperature at 48.9°C to 54.4°C (120°F to 130°F) for 12 hours.

3) Hydrogen peroxide low-temperature plasma sterilization

① It should be carried out in a dedicated hydrogen peroxide low-temperature plasma sterilizer. A sterilization process includes several cycles. Each cycle includes five steps: vacuuming, hydrogen peroxide injection, diffusion, plasmaization, and ventilation.

② The operation manual of the hydrogen peroxide low-temperature plasma sterilization manufacturer should be followed, and the appropriate sterilization procedure should be selected according to the type, packaging, loading, and method of the sterilized items. Sterilization parameters such as hydrogen concentration and dosage, sterilization time, etc.

4) Low-temperature steam formaldehyde sterilization

① It should be carried out in a low-temperature steam formaldehyde sterilizer. Procedures should include: preheating, pre-vacuuming, venting, steam injection, humidification, temperature rise, repeated formaldehyde evaporation, injection, formaldehyde penetration, sterilization (at preset pressure, temperature for a certain period of time), repeated steam flushing Formaldehyde in the sterilization chamber is repeatedly air washed, dried and cooled to restore the normal pressure in the sterilization chamber.

② According to the requirements of the low-temperature formaldehyde steam sterilizer, use 2% compound formaldehyde solution or formalin solution (35%~40% formaldehyde) for sterilization, each cycle of 2% compound formaldehyde solution or formalin solution (35% to 40% formaldehyde) The dosage varies according to the loading amount. The sterilization parameters are as follows: the temperature is 55℃～80℃, and the sterilization maintenance time is 30min～60min.

Note: Refer to the respective precautions for the standard disinfection and sterilization methods of the Ministry of Health WS/T367-2012 “Technical Specifications for Disinfection in Medical Institutions”.

Recommendation: Once a method of disinfection and sterilization of endoscopes has been selected, it is recommended that this method should always be used. If the endoscope is disinfected and sterilized by the cross method, the service life will be reduced.

4. Sterilization and disinfection of accessories

① The sheath, obturator, manipulator, connecting bridge, surgical instruments, etc. used together with the endoscope should also be sterilized after cleaning.

② Pressure steam sterilization is the first choice for stainless steel metal accessories, which is the most effective sterilization method at present.

③ Ethylene oxide sterilization, the operating parameters, and precautions are the same as those of the endoscope.

④ Sterilize by soaking in 2% glutaraldehyde for 10h. All parts should be immersed in disinfectant, and all channels should be filled with disinfectant.

⑤ Hydrogen peroxide low-temperature plasma sterilization and low-temperature steam formaldehyde sterilization. For specific methods, see the standard of WS/T367-2012 “Technical Specifications for Disinfection in Medical Institutions” and the instructions for use of sterilization equipment.

⑥ For optical cables, cameras, and other accessories, it can be wiped and disinfected twice with 75% alcohol cloth, or a disposable sterile plastic sleeve can be used to achieve the purpose of isolation and disinfection, but the contact area should still be wiped and disinfected with alcohol.

⑦ Parts with joints or valves should be fully opened during disinfection.

⑧ The parts after fumigation or immersion disinfection must be thoroughly rinsed with isotonic saline or distilled water to wash away the disinfectant remaining on the surface of the parts.

⑨ For other unmentioned matters and specific methods, please refer to the standard of the Ministry of Health WS/T367-2012 “Technical Specifications for Disinfection of Medical Institutions”.

The operation methods, steps, and technical parameters of various cleaning, disinfection, sterilization, and chemical agents listed in this chapter are for reference only. The specific and detailed operation methods, steps, and various parameters should be subject to the instructions for use of the equipment and drugs.

During the entire cleaning, disinfection, and sterilization process, endoscopes and accessories should be placed neatly and orderly to avoid overlapping.

Overall, the sterilization process for medical rigid endoscopes is critical for ensuring patient safety and preventing the transmission of infections between patients. It is important to follow the manufacturer’s instructions and to adhere to local regulations and guidelines to ensure effective and safe sterilization.