Prevention and Treatment of Common Electronic Colonoscopy Malfunctions

Electronic colonoscopes are well-structured, high-performing, flexible, easy to operate, provide clear images, and are user-friendly. Their precision, complexity, and delicacy are considerable. Therefore, correct operation and good maintenance can extend their lifespan, and the prevention and handling of common malfunctions are particularly important. The prevention and handling of common electronic colonoscope malfunctions are introduced below:

1. Loss of Seal in the Scope Body

The main feature of an electronic colonoscope is its built-in miniature camera system with a charge-coupled device (CCD), which is the "heart" of the electronic colonoscope. Since the examination, treatment, cleaning, and disinfection of the colonoscope all take place in a liquid environment, the overall seal of the scope body is particularly important. Common areas where the seal of the scope body can be compromised are the bending rubber and the biopsy channel.

1.1 Bending Rubber

At the front end of the insertion part of the scope, there is a section approximately 10cm long that can be freely bent. This section is covered by very thin rubber and is the most "delicate" part of the entire scope. If it accidentally comes into contact with the cart, the table, the edge of the cleaning and disinfection tank, or sharp objects and instruments, it can cause damage or small holes in the bending rubber, leading to a loss of seal in the scope body. Therefore, operators should be extremely careful after each examination. During the cleaning and disinfection process, special care should be taken to avoid cleaning and disinfecting it with sharp or pointed instruments.

1.2 Biopsy Channel

During the examination and treatment with an electronic colonoscope, the biopsy channel is the necessary pathway for examination and treatment instruments. If the operation is improper during the insertion of instruments, it can easily lead to damage of the biopsy channel, resulting in a loss of the scope body's seal, leakage, and damage to the camera system. The following points should be noted when inserting instruments through the biopsy channel:

① First straighten the scope body. The movement of inserting the instrument should be gentle, with appropriate force, minimizing wear on the inner wall of the biopsy channel. Adjust the angle after the instrument has extended from the biopsy channel.

② When performing electrocoagulation or laser treatment, be sure to step on the switch only when the probe has extended from the biopsy channel and is aimed at the treatment site.

③ If you encounter resistance when inserting an instrument, never force it.

2. Blurred or Spotted Images

Malfunctions such as damage to the bending rubber and biopsy channel can cause leakage in the scope body, leading to CCD damage. If image blurring and spotting are caused by leakage in the scope body, they should be addressed promptly; otherwise, permanent spots may appear on the image, affecting diagnosis and even causing damage to the CCD [1]. However, under normal circumstances, if blurred or spotted images appear, it is often due to the lens being covered with mucus or other contaminants. First, flush the lens surface with water and air. If there is still no improvement, stop using it immediately; it may be due to leakage in the scope body, and it should be sent to a repair station as soon as possible.

Given the above, damage to the bending rubber and biopsy channel is often not immediately detectable. Therefore, to detect problems promptly and prevent CCD damage, it is best to perform a leak test once a day after cleaning and disinfection. If a leak is detected, send it to a repair station as soon as possible to avoid unnecessary losses.

3. Angle Knob Malfunction

One is that the angle knob becomes loose, and the bending section cannot be adjusted to the desired angle.

The other is that the angle wire breaks.

Its normal lifespan is determined by the number of examinations performed. Improper operating techniques can also affect its lifespan. Therefore, when adjusting the angle, operators should avoid excessive force and excessive angle adjustment. They can use their hands or body to rotate the scope body to adjust the angle, minimizing angle adjustments. Changing the patient's position can also adjust the angle, thus extending the lifespan of the wire.

4. Air/Water Supply Obstruction is the Most Common Malfunction

First, repeatedly press the air/water supply buttons. If addressed promptly, the obstruction can usually be cleared. If it remains unobstructed, the reason is that there is a nozzle at the tip of the colonoscope. Because the nozzle cavity is very small and at a right angle, it is easily blocked. Conventional flushing is difficult to quickly clear a blocked nozzle. In practice, the author believes that the conventional cleaning and disinfection procedure [2], when a nozzle blockage occurs, requires repeated flushing, a longer soaking process, and may even result in incomplete cleaning, affecting the disinfection effect and causing cross-infection in the hospital. It also fails to fully utilize the diagnostic and therapeutic value of the colonoscope. Only on the basis of conventional cleaning in a water tank, mechanical cleaning of the nozzle is necessary. That is, a specially made X-ray film is gently inserted along the shape of the nozzle from the nozzle opening to the connection end of the nozzle and the air/water supply tube, achieving mechanical cleaning of the entire nozzle. This solves the above problems, ensuring thorough cleaning and effective disinfection of the colonoscope.

This simple mechanical cleaning and clearing method is introduced below:

4.1 Operating Method

4.1.1 First prepare a 50mm long and 2mm wide piece of old X-ray film. (Because X-ray film has a certain degree of rigidity, toughness, and plasticity, this characteristic is used for mechanical cleaning of the nozzle.)

4.1.2 Place the colonoscope in the water tank for conventional cleaning → mechanical cleaning of the nozzle (in the water tank, use the prepared film strip, with the 2mm wide end gently inserted along the shape of the nozzle for about 10mm, remove and reinsert, repeat 2-4 times to mechanically clear the blockage). The remaining operations are the same as usual, i.e., multi-enzyme solution tank soaking → water tank cleaning → disinfectant tank soaking and disinfection → sterile distilled water tank rinsing, etc. [2].

4.2 Results

4.2.1 This method significantly improves work efficiency, saving an average of 2-5 minutes per cleaning. Moreover, the cleaning is thorough, and the disinfection effect is good. It prevents hospital cross-infection and fully utilizes the diagnostic and therapeutic value of the colonoscope.

4.2.2 This method does not damage the scope, is simple, readily available, and cost-effective, and is worthy of widespread clinical promotion. To avoid or reduce the occurrence of air/water supply obstruction or nozzle blockage.

The following points should be noted during operation:

① Immediately supply air and water while suctioning to prevent suction into the nozzle.

②Distilled water should be used in the bottle.

③Use distilled water or filtered water to clean the colonoscope [3].

④Regularly check and replace the rubber ring inside the bottle cap as needed.

⑤If the air and water supply weakens, and the air and water supply pipes are confirmed to be unobstructed, consider whether there is a problem with the host's air pump.

⑥Regularly apply the included silicone oil to the air and water buttons to ensure smooth operation.

⑦The bowel cleansing effect can reach Grade Ⅰ bowel cleanliness, where Grade Ⅰ indicates a clean bowel with no mucus or fecal residue [4].

5. Host Maintenance

The main maintenance of the electronic colonoscope host is to secure the instrument. The host has many rear line plugs; excessive plugging and unplugging may cause poor contact, directly affecting imaging. The host power supply should preferably be through a voltage regulator. Avoid frequent switching on and off of the system during use to extend the life of the cold light source [5]. The host should also be protected from moisture, dust, and direct sunlight to maintain good heat dissipation.

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