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A brief discussion on surgical shadowless lamp

2023-07-20_15-06-25 The shadowless lamp is one of the basic equipment in the operating room, and surgery is inseparable from its lighting support. How much do you know about the shadowless lamp every time you turn it? Let us learn together from the basic knowledge, use, adjustment and maintenance of shadowless lamps to improve our understanding and mastery, so as to help us use shadowless lamps more scientifically and rationally.

1. Overview of surgical shadowless lamps 1. Shadowless lamps: used for lighting surgical sites, providing high brightness, good color temperature, shadowless, and well-focused lighting equipment for human tissues and organs in incisions and body cavities.
2. Can shadowless lamps really eliminate shadows? Under normal circumstances, when light shines on an opaque object, a shadow will be produced. The darkest part of the shadow in the middle is called the umbra, and the gradually lighter part around it is called the penumbra. The round lamp panel of the shadowless lamp is equipped with lights that illuminate in all directions, which increases the area of ​​the light source, making the umbra lighter and the penumbra less visible, achieving a shadowless effect so that the operation can proceed smoothly.
3. The operating room shadowless lamp should have the following characteristics: ① Shadowless, cold light, multi-reflection system design to ensure shadowlessness in the operating area; cold light source filter and cold light reflector to minimize thermal radiation. ② The structure is light and has a wide adjustment range and good stability. It has a detachable adjustment light handle, which is convenient for the surgeon to adjust at will; the lighting required for surgery can be adjusted by adjusting the light handle and the central control panel. ③The shape design of the lamp meets the requirements of laminar flow purification operating rooms. It is best to use multi-head hollow lamps to ensure that the purified air in the operating room can smoothly circulate by convection and keep the operating area sterile. ④ The color of the light is lifelike and close to natural light, making it easy for people to distinguish the subtlest differences in tissues and reducing the eye fatigue of operating personnel. ⑤ A central camera system is reserved for teaching, scientific research and management.
4. Classification of shadowless lamps: ① According to the type of light source, they are divided into halogen lamps and LED lamps. The light-emitting principle of halogen lamps is the energy conversion of electricity-heat-light, that is, electricity is heated by the filament and then produces light. This light-emitting method has low efficiency and high temperature. LED lights are cold light sources, direct electro-optical conversion, low energy consumption, and are low-temperature lights. ②From the appearance design, it can be divided into ceiling shadowless lights, wall-mounted shadowless lights, mobile shadowless lights, headlights, etc. ③ In terms of functional requirements, it can be divided into single-head, multi-head, double-mother shadowless lights, mother-child lights, twin lights, inspection lights, as well as camera functions and multi-arm monitor mounts.
5. Double-headed lights have become the first choice for operating rooms in most hospitals: one lamp head serves as the main light, providing main lighting; the other lamp head serves as an auxiliary light, providing auxiliary lighting to make up for the blind spot of the main light. In addition, when there is a problem with the main light, Backup lighting can also be provided immediately.
2. Key points for operating the shadowless lamp: 1. Check the appearance of the shadowless lamp and each joint arm before use to confirm whether the function is normal. 2. Pay attention to the switch sequence to avoid damaging the bulb. The opening sequence is generally: turn on the main power switch → operating light switch → adjust the brightness. The closing sequence: adjust the brightness to the minimum → turn off the operating light switch → main power switch. A suitable lighting environment can allow medical staff to “see clearly and Deku.” To see clearly means that the colors are not distorted, organs can be distinguished, and there are no shadows. During the operation, it is a prerequisite that the color remains unchanged for a long time. For example, red is red. If it is illuminated by a light source and the original color changes to other colors, it will inevitably cause the doctor to misjudge; when the incision is deep, due to the influence of the surgical instruments Occlusion may form a partial shadow in the deep cavity, obstructing the doctor’s view. If you want to see “clearly”, the surgical shadowless lamp can meet the requirements by maintaining a constant color rendering index, adjusting the color temperature and having a high shadowless effect.
“Looking for a long time” means watching comfortably and for a long time. For doctors, the light spot formed in the surgical field is relatively soft and does not flicker, which can effectively reduce visual fatigue. In addition, if a doctor stands under a shadowless lamp for a long time, part of the light will directly shine on the back of the head. If the lamp has a high calorific value and the light emitted does not block infrared rays, the temperature of the doctor’s head will rise, and it may also cause symptoms in patients. The temperature of the surgical field increases and body fluids are lost. Some of these factors can be adjusted manually to meet surgical needs, while others are determined by the design standards of the shadowless lamp and cannot be adjusted in real time.
3. Adjust the shadowless lamp 1. Adjust the mobility. The shadowless lamp cantilever can be moved vertically up and down or horizontally rotated according to the function, and the joints of each joint arm can be rotated 340 degrees or 360 degrees. Before surgery, the operating bed and shadowless lamp cantilever should be adjusted appropriately according to the name of the operation, so that the cantilever and the bed are in a straight line. The positions of the two shadowless lamps should be roughly adjusted so that the big lamp is perpendicular to the surgical field, and the small lamp can move in a circle, and ensure that the two shadowless lamps can be moved in a circular motion. The cantilevers of the shadowless lamps will not cross. After the switch is turned on sequentially after the operation begins, the circulating nurse can adjust the light along the surgeon’s field of view, or the operating staff can use a sterile handle to adjust the light. When installing the sterile handle, you should clearly hear two “clicks”, indicating that the installation is in place and the sterile handle is in normal working condition.
2. Illuminance adjusts the lighting intensity and the luminous flux of visible light received per unit area. Abbreviated as degree, unit is lux. A quantity used to indicate the intensity of light and the degree to which an object’s surface area is illuminated. Illuminance can be simply understood as whether the light is bright enough. Illumination uniformity refers to whether the lighting is uniform enough or not. The illumination should have a certain height, and the light illumination surface should be larger and more uniform. The larger the lamp panel of the shadowless lamp (single head lamp) or the more heads it has, the better the irradiation depth will be, and the more suitable it is for deeper surgeries. The illumination can be adjusted according to surgical needs. The illumination of the shadowless lamp is the brightest at a position 1000mm away from the glass surface of the lamp head. The light column gradually attenuates upwards and downwards. The vertical area range of 20% to 10% of the highest brightness can theoretically meet the needs of surgery. The working distance of shadowless lamps is generally 70 to 160cm, and the best is 100cm. The illumination range is 40,000 to 160,000 lux. Exceeding 160,000 lux will harm the eyes of medical staff. Therefore, the European Electrotechnical Organization and China’s shadowless lamp industry standards stipulate that the maximum illumination of shadowless lamps should be less than or equal to 160,000 lux.
3. Light spot adjustment In the lighting area, the edge illumination of the light reaches the entire area included in 10% of the central illumination. At this time, the specific shape formed by the light within this range. The illumination beam diameter of the shadowless lamp ranges from 10 to 25 cm, and has an adjustable spot function. Different spot sizes can be adapted to different sizes of surgical areas.
4. Color temperature adjusts the color temperature. When an absolute black body is heated to a certain temperature, the spectral component of the light emitted by the black body is called the color temperature at this temperature. When heated from absolute zero (-273 degrees), the color changes from black to red to yellow to white, and finally emits blue light. The unit of measurement is Kelvin. Color temperature is a measure of the color of a light source. Usually, the light seen by the human eye is composed of the spectrum of seven colored lights. But some of the light is bluish and some is reddish. Color temperature is a method specifically used to measure and calculate the color components of light. The smaller the color temperature value, the more it is biased towards yellow warm light, which can easily make people tired; the larger the color temperature value, the more it is biased towards white cold light, which can easily make people excited. The color rendering of the lighting source in the operating room should be close to natural light, and the color temperature should be between 4000K-5000K. Some high-end LED shadowless lamps will add a color temperature adjustment function mode to reduce the doctor’s eye fatigue or increase the doctor’s excitement, and make it easier to distinguish the surgical field tissue in different types of surgeries.
4. Other characteristics of the shadowless lamp 1. Strobe, under the alternating current of 220V 50HZ (the current completes 50 sine wave conversions in 1 second), it produces 100 light and dark flashes per second. The larger the current, the brighter the headlight, and the smaller the current. The light dims, thus changing from dark to light and then from light to dark. The brain cannot actually distinguish these changes (the perceptible changes are within 30HZ), but the eye muscles that control pupil contraction can detect it. If the shadowless lamp flickers, it will increase the burden on the doctor’s vision and easily cause misunderstandings, which may lead to adverse consequences. It can be driven by a built-in or external power supply so that the shadowless lamp does not require a ballast.
2. Glare, due to unsuitable brightness distribution in the field of vision, or extreme brightness contrast in space and time. Glare affects doctors’ vision and vision, easily causes eye fatigue, and is not conducive to doctors’ operations. The surgical shadowless lamp can be designed to minimize and eliminate the infrared and glare components in the shadowless lamp through the lens and filter design; during the operation, the glare caused by the beam hitting the surgical instruments should also be avoided as much as possible.
3. Color rendering, the impact of the lighting source on the color table of the object is caused by the observer consciously or unconsciously comparing it with the color table under the reference light source. By comparing it with the object under the reference or benchmark light source of the same color temperature Comparison of appearance colors shown. It is an indicator of color authenticity. The higher the color rendering index, the closer the color of the object is to the true color. If you are exposed to a light source with poor color rendering for a long time, the sensitivity of the cone cells of the human eye will decrease, and the brain will intentionally or unintentionally concentrate more on distinguishing things, which will easily cause eye fatigue and affect vision. The color rendering index of the shadowless lamp in the operating room should be close to natural light (Ra=100).

5. Maintenance of shadowless lamps
1. Cleanliness maintenance: Clean the surface of the shadowless lamp with clean water or a weak alkaline solvent before daily use or after each operation. When contamination of blood or body fluids occurs, follow the principle of cleaning first and then disinfecting. Use neutral disinfectants to avoid strong acids and alkalis coming into contact with other surfaces. Avoid using chlorine-containing cleaners (damage metal) and alcohol-based cleaners (damage plastics and paint). Sterile lamp handles should be sterilized using low temperature methods.
2. Functional maintenance: Check the function of the shadowless lamp every day to keep it in standby mode. Check the status of the bulb: Place a piece of white paper in the working area of ​​the shadowless lamp. If an arc-shaped shadow appears, it means that the bulb is in abnormal working condition and should be replaced. Regularly check the main body of the shadowless lamp, function keys and joints for looseness. Regularly check the damping of the shadowless lamp to prevent the lamp head and arm from drifting. Regularly check the spring strength of the shadowless lamp to avoid insufficient or overloaded elasticity. Annual inspections are performed by certified engineers. If any problems are found, they should be reported to the equipment department or manufacturer for maintenance in a timely manner.

Post time: Nov-09-2023