Answer:
(From Grabb and Smith CD ROM:)
Individuals who use lasers or assist with laser procedures must be aware of the potential hazards. Safe procedures decrease the incidence of accidents and injury. Guidelines for laser use were published by the American National Standards Institute. These guidelines provide a protocol for laser safety. The following discussion addresses a variety of laser hazards.
Beam Hazards
Ocular Hazards:
Lasers pose a significant ocular hazard. Both direct beam and the reflected beam can permanently damage the eye. The type of ocular damage that ensues with laser exposure depends on the wavelength. Laser light of visible and near infrared (IR) laser can be focused to a small point within the retina, increasing the intensity by 100,000 times. Ultraviolet and far IR light (i.e., CO2) can damage the anterior segment of the eye including the lens and cornea. Several measures are taken to avoid ocular injury. Protective eyewear (goggles, safety glasses, or eye shields) are worn by all individuals in the laser room. Reflective surfaces are removed from the operating space and special anodized surgical tools are used to minimize specular reflection. Finally, laser beams are never pointed toward the eyes.
Skin and Surrounding Tissue Hazards:
If the laser beam encounters skin not intended for treatment, burns can occur. Aiming beams helps to ensure that laser exposures are directed at the intended target. When carbon dioxide lasers are used, the treatment field is isolated with wet gauze to avoid burning adjacent skin.
Environmental Hazards
Fire:
Several fires have been reported in association with laser use. Prudent safety precautions diminish the probability of fires. Extreme caution is exercised when oxygen is present in anesthetized patients. When supplemental oxygen is required, closed systems such as endotracheal tubes and laryngeal mask airways should be considered. Flammable substances are removed from the operating field, including any dry gauze, alcohol, and the patient’s personal care products, such as perfume, nail polish, or hair gel. Fire extinguishers should be also available nearby.
Plume and Splatter:
The use of carbon dioxide laser creates a plume of aerosolized particles that is potentially harmful to the staff as well as the patient. Pathogens, including human papilloma virus (HPV), human immunodeficiency virus (HIV), and hepatitis B deoxyribonucleic acid (Hep B DNA), have been isolated from the laser plume, as well as viable bacteria. Additionally, the particles within the plume were shown to cause pneumonia, bronchiolitis, and emphysema in laboratory animals and may pose the same risk to humans. Several safety measures reduce the potential damage associated with laser plume. High flow rate smoke evacuators are used whenever the laser is in use. The filters as well as the tubing of the smoke evacuators are changed frequently to ensure optimal suction and filtering. The suction device is kept within 1 to 2 inches of the origin of the plume. Additionally, all personnel should wear laser masks capable of filtering particles as small as 0.3 mm
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The use of Q-switched lasers produces a back splatter of tissue that contains intact, viable cells capable of infectivity. Currently many lasers are equipped with protective sleeves to contain the back splatter. As with carbon dioxide lasers, masks and smoke evacuation are also useful.
Machine Hazards:
Lasers require high-voltage power supplies and therefore electrocution is a potential hazard. However, most medical lasers have built-in safety controls that protect the user and patient from electrical danger. If the machine malfunctions, only experienced laser engineers should attempt to repair the system. Some lasers contain toxic dyes, which should be handled with appropriate caution to reduce risks.
General Safety
Following certain guidelines ensures safe laser use. Most importantly, all personnel who use or assist with lasers should be trained in laser safety. When lasers are in use, illuminated signs or door signs help to signal others outside the room not to enter. During procedures, proper eyewear, gloves, and masks should be worn and smoke evacuators should be used as indicated. Fire extinguishers should also be readily available especially when oxygen is in use, and the beam should never be pointed toward unintended targets. When not in use, lasers should be kept in the standby mode, and shutters should be closed.