Composition and fault diagnosis of medical endoscope
Endoscopic surgery is a model of high-tech applications in minimally invasive clinical disciplines such as electronics, optics, and photography. With the reform of the national medical system, the advancement of medical technology, and the popularization of advanced medical equipment, endoscopic equipment systems have become more and more widely used in hospitals at all levels. The endoscope equipment system will be called differently when it is used in various clinical departments, such as: ventriculoscopy, thoracoscopy, hysteroscopy, ureteroscopy, prostatic resection, discoscopy, arthroscopy, laparoscopy, and so on. Among them, laparoscopy and hysteroscopy are the most popular. Unlike traditional surgery, it is performed in a closed cavity. Therefore, the quality of the equipment directly affects the effect of the operation, and the correct use of the equipment is directly related to the smoothness and success of the operation. Nowadays, there are many brands of endoscopes and their functional designs have their own merits, but the basic principles are the same.
一. The composition of the system
The medical endoscope system is mainly composed of an equipment system and a surgical instrument system. Surgical instrument systems are mainly classified by department or operation name. There are endoscopes, special instruments, surgical instruments and disposable surgical consumables used in various departments. I won't introduce it in detail here, but we will mainly discuss the structure of the equipment system below.
In the equipment system, we can usually be divided into: camera imaging system, image recording system, light source system, artificial pneumoperitoneum system, fluid pressurization system, electrocoagulation and electrosurgical resection system, dynamic ablation system, flushing and suction system and so on.
Composition and fault diagnosis of medical endoscope
(1) Camera imaging system: The system includes a monitor and a camera. There are two types of monitors: conventional CRT and liquid crystal, and the cameras have two types: single CCD and 3CCD. Nowadays, most high-end users are LCD monitors with 3CCD cameras.
(2) Image recording system: Many hospitals now choose computer-based graphic workstations. The system is divided into two parts: computer hardware and graphic acquisition software.
(3) Light source system: also known as cold light source. The cold light source bulb is filled with halogen and xenon, and its output power is 70-400W. The 300W xenon light source is now the mainstream product. Its outstanding feature is strong light, with a color temperature of 5600-6000k, which is similar to sunlight and covers the entire wavelength range from ultraviolet to infrared.
(4) Artificial pneumoperitoneum system: connect the insufflator to the carbon dioxide cylinder, unscrew the valve on the cylinder, and then turn on the pneumoperitoneum. According to the needs of the operation, select the preset pressure value. When the pressure in the abdominal cavity exceeds or falls At the set value, the automatic carbon dioxide insufflator can automatically start or stop gas injection.
(5) Liquid pressurization system: systems such as joint pumps, dilatation pumps, and bladder pumps are mainly used to pressurize liquids into a cavity, and then perform operations in the cavity with instruments.
(6) Electrocoagulation and resection system: high-frequency electrosurgical surgery is often used in ordinary open surgery and minimally invasive surgery.
(7) Power ablation system: Power planing system and ion ablation knife are often used in sinusoscope and arthroscopic surgery. Although these two devices are expensive, they greatly shorten the time and reduce the cost of surgery. The risk of surgery.
(8) Flushing suction system: The flushing flow rate of the equipment should be at least 1 L/min.
二. Common faults and maintenance methods of equipment systems
After long-term maintenance of equipment in the operating room, it was found that the faults can be divided into complex faults, medium faults and simple faults according to the difficulty of repair and the size of the fault. According to statistical analysis, the probability of complex faults is only 15% (such as the host computer, main circuit is broken). Due to various conditions, this part of the fault is difficult to complete in a short period of time on site in the operating room, and the machine must be weaned for maintenance. Moderate faults account for about 25%, while simple faults account for about 60%, of which faults caused by improper use or operating errors account for about 30%. No matter what kind of failure, we must understand the working principle of the instrument and deal with it with the help of rich maintenance experience.
1. Common faults of camera imaging system
(A) The image is disturbed. Generally, it is because of the interference to the line when using high-frequency equipment such as electric knife. At this time, what we need to check is whether the camera is connected to the shielded wire in the connection. Another situation is that interference stripes will appear when high-frequency equipment is not used. At this time, the shielding layer of the connecting wire and signal wire is worn out due to long-term use. It depends on whether there is a problem with the connection of the camera or the entire wire body is aging. The former needs to be re-soldered, while the latter needs to be replaced with the connecting wire. At present, the price of replacing the original imported 3m connecting wire is about 10000RMB. Therefore, try to avoid the wire being run over by the instrument cart or surgical cart on the ground during use.
(B) The image is color cast. When the color of the scene cannot be restored after the white balance and excluding the influence of other supporting equipment, we believe that it may be caused by wire aging signal transmission defects, or it may be the aging and deterioration of the camera circuit components, or it may be caused by the aging of the camera CCD . At this time, we only need to replace the corresponding accessories.
(C) Malfunctions of the camera host are generally rare. If there is a software failure (program failure), you can only get the manufacturer back to replace the program chip.
2. Common faults of the image recording system
(a) The foot switch fails.
(b) Poor contact of the video screen cable.
(c) Computer hardware failure.
(d) System software or image acquisition software malfunctions.
3. Common faults of the light source system
(a) The light is dim. Excluding the cause of the grating occlusion, it is basically certain that the bulb is approaching its service life, and you can replace it with a new bulb. The service life of xenon light bulbs is generally designed to be 500 hours. If the light source system has a life timer device, this problem can be easily solved.
(b) The bulb does not light up when turned on. If the reason for burning the bulb is ruled out, then the problem often lies in the high-voltage ignition circuit of the main engine, because the machine will generate tens of thousands of volts pulse high voltage when the machine is turned on, and the components will age very quickly. Note that you cannot use a multimeter to check the pulse high voltage at this time.
4. Common faults of artificial pneumoperitoneum system
(a) The pressure display is incorrect. This is mostly due to the damage of the gas pressure sensor. If the machine is designed with a group of multiple differential pressure sensors working at the same time, generally when one is aging or contaminated and cannot work, we have to replace this group of sensors, otherwise only one of them will be replaced, and the others The life of the sensors in the same group is also close to critical.
(b) Inaccurate flow. If the gas flow sensor is damaged, replace it. Sometimes the flow is calculated by the pressure difference, at this time we have to replace the new pressure difference sensor.
(c) Equipment leaks. Many cases are caused by the aging of the instrument sealing ring. However, there are also reasons for the leakage of the equipment mechanical pressure reducing valve and the damage of the solenoid valve. This is easier to judge and repair.
5. Common failures of liquid pressurized systems
(a) The peristaltic pump is damaged.
(b) The liquid pressure sensor is damaged. The principle is basically the same as that of a gas pressure sensor.
(c) The internal circuit of the equipment is damaged.
6. Common faults of electrocoagulation and cutting system
(a) The equipment accessories are damaged. Such as foot switch, negative plate lead, connecting lead and other commonly used fragile accessories.
(b) Electric cutting, electrocoagulation, bipolar failure. Inside the device, these parts are composed of different circuit modules. We can repair or replace the corresponding module circuit according to the fault phenomenon.
7. Common failures of power and ablation systems
(a) The power system is mainly due to the wear of the planing head and the high-energy motor in the planing handle. The replacement of the motor is selective, and not every motor has replacement parts. Therefore, special attention must be paid to protection during disinfection and use.
(b) The main reason for the ablation system in surgical applications is the loss of the blade. However, equipment failures are mostly circuit failures, and usually start from the output part.
8. Common faults of flushing suction system
(a) Insufficient pressure or suction. The two-way pump in the equipment is aging, or the negative pressure bottle is leaking.
(b) The equipment cannot be turned on. Generally, liquid enters the equipment. It is enough to clean up the misabsorbed liquid without burning the relevant parts.