8
Understanding Laser Safety in Dentistry
Vangie Dennis1, Patti Owens2 and Georgios E. Romanos3
1 Executive Director Perioperative Services, Atlanta Medical Center, Atlanta, GA, USA
2 President of Aesthetic Med Consulting International, LLC
3 Stony Brook University, School of Dental Medicine, Stony Brook, NY, USA
8.1 Laser Safety
When lasers are introduced into a healthcare environment, whether in a hospital, surgery center, physician’s office, or a dental office, healthcare professionals must be prepared to address issues of safety for both the staff and the patient. All lasers present hazards to patients and to the individuals utilizing them as well as anyone present in the area in which they are being activated. This equipment should be utilized in accordance with established regulations, standards and recommended practices, manufacturer’s recommendations, and institutional policies. Laser safety is based on knowledge of the specific laser being utilized, its instrumentation, mode of operation, power densities, action in tissues, and risk assessment.
8.2 International Laser Standards
The International Electrotechnical Commission (IEC). IEC 60825‐1 3.0:2014, 60601‐2‐22 Ed. 3.1:2011 and 60825‐8:2006 are international standards that provide the safe manufacturing and use of medical‐surgical, cosmetic, and therapeutic lasers. Since this is a global economy, dental lasers manufacturers will need to be aware of the numerous international specifications and performance standards.
8.3 Regulatory Agencies and Nongovernmental Organizations
8.3.1 Food and Drug Administration
All laser products manufactured or imported into the United States are subject to the Food and Drug Administration’s (FDA) Radiological Health Regulations (21 CFR Parts 1000–1050). The FDA’s authority to regulate laser products is granted by the Federal Food, Drug, and Cosmetic Act. Under these regulations, the manufacturer must build their product to comply with a performance standard (1040.10 & 1040.11), self‐certify the product complies to the applicable parts of the performance standard (1010.2), affix identification information to the product (1010.3), and submit reports and maintain records (1002). These requirements must be met before the manufacturer can leave the product with another entity. Medical laser products are subject to additional requirements (21 CFR Parts 800–1299). Some requirements apply to medical devices before they are marketed (premarket requirements), and others apply to medical devices after they are marketed (postmarket requirements). It is important to be acquainted with the organizations, laws, and standards regulating or affecting the use of lasers in a medical setting. Healthcare professionals can then develop and implement an appropriate laser safety program.
8.3.2 FDA Center for Devices and Radiological Health
All medical lasers are regulated by the FDA under the Medical Device Amendments to the Food and Drug Act. Any medical device that is manufactured, repackaged, relabeled, or imported into the US must meet FDA regulations. These regulations are enforced by the National Center for Devices and Radiological Health (CDRH), which is a regulatory bureau of the FDA. The FDA regulates more than 250 types of lasers including those intended for medical and surgical use. Medical, surgical, aesthetic, and dental lasers are usually classified as class II medical devices, which indicate that they have a moderate to high risk to the patient. Manufacturers must conform to all of the federal safety requirements including performance standards involving compliance with engineering, electronics, and hardware specifications. Manufacturers are also required to conform with FDA labeling requirements along with supplying maintenance and procedure manuals. Medical laser devices must be cleared or approved by the CDRH prior to any marketing or testing of a laser for a particular clinical application or use.
In addition, the FDA has been empowered by the US Congress to provide regulations for electronic products that emit radiation. The regulations created by the FDA require the manufacture of laser products to produce a product that complies with the performance standard for laser products 21CFR 1040.10 and.11. This standard is referred to as the Federal Laser Product Performance Standard (FLPPS). The FLPPS specifies a hazard classification scheme based on a laser product’s ability to cause damage to the eye and skin It also provides requirements for hazard labels, user information, and performance requirements for engineering features such as protective housings, safety interlocks, and viewing optics incorporated into the product. The control measures specified in the ANSI standard can be applied to the products classified under the FLPPS or the conditions of Laser Notice No. 56.
8.3.3 American National Standards Institute
The American National Standards Institute (ANSI) is a voluntary organization of experts, including manufacturers, consumers, scientific‐technical and professional organizations, and government agencies who determine industry consensus standards in technical fields. ANSI’s mission is to provide a practice standard for the safe use of lasers and laser systems for diagnostic and therapeutic use in healthcare facilities. The ANSI Z136.3‐12018 “American National Standard for Safe Use of Lasers in Health Care” is the national benchmark standard. The first cohesive blueprint for building a safe and effective dental laser program is outlined in the ANSI Z136.3 Standard. ANSI states that an adequate program for control of laser hazards be established in every healthcare facility that utilizes medical lasers. The program must include provisions for a laser safety officer, education of users, protective measures, and management of accidents. ANSI Z136.3 covers many areas of lasers and their safe use including terminology, hazard evaluation, classification, control measures, and administrative controls. Federal legislation and state laser safety regulations, as well as professional and advisory standards, are based on the ANSI standard. This standard of practice is also the most cited source during medical litigations.
8.3.4 Occupational Safety and Health Administration
With the Occupational Safety and Health Act of 1970, Congress created the Occupational Safety and Health Administration (OSHA). OSHA’s primary goal is for employers to keep their workplace free of serious recognized hazards. OSHA is concerned primarily with the safety of healthcare workers, and their enforcement can be administered on a national or state level. OSHA can enforce the ANSI standards even though they do not have specific legislated regulations governing laser safety in healthcare facilities. OSHA can cite violations under the General Duty clause if the level of compliance is not satisfactory, and they view employees are at risk.
OSHA can also issue citations utilizing CFR Part 1910, which provides the general industry standards for employee protection. Under the 1910.132 Personal Protective Equipment, this regulation addresses the need for the appropriate protectant safeguards, including laser safety eyewear, face shields, masks, and protective clothing. OSHA furthermore states under 1910.133(a)(1), that “the employer shall ensure that each affected employee use appropriate eye and face protection when exposed to eye or face hazards from flying particles, molten metal, liquid chemicals, acids or caustic liquids, chemical gases or vapors, or potentially injurious light radiation.” In addition, the employer needs to aware of the blood‐borne pathogen regulation 1910.1030, pertaining to employee exposure to blood and other potentially infectious material (OPIM). Laser plume is generated from vaporizing laser devices, such as the CO2, Er:YAG, Ho:YAG, Er,Cr:YSGG lasers, which produce airborne contaminants, toxic gases, organic compounds, and splatter of blood‐borne particles.
8.4 State Regulations
State regulations, including FDA, are the only guidelines for laser safety that are backed by legislative action. The concern over laser safety is reflected in the increasing number of states that are enacting medical laser safety legislation. Regulations governing the safe use of lasers present healthcare personnel with a complex set of guidelines. Only FDA and individual state enactments are supported by legislation. All other guidelines are recommended practices or standards and are based on the ANSI Z136.3 practices.
8.5 Nongovernmental Controls and Professional Organizations
8.5.1 American Society for Lasers in Medicine and Surgery
The American Society for Lasers in Medicine and Surgery (ASLMS), in 1980, issued reports that were adopted as recommendations by the society’s members. In 1990, the board of directors released nine recommended perioperative practices relating to patients undergoing laser procedures. This included assessment, nursing diagnosis, planning, implementation, and evaluation of nursing care. Position statements are available to provide practice guidelines for physician education and credentialing along with nonphysician laser use. In 2017, ASLMS drafted and approved their “Position Statement on Lasers and Energy Device Plume” addressing the hazards of working with devices that caused vaporization and ejected tissue plume. The utilization of a plume evacuator, the appropriate personal protective equipment (PPE), and the possible use of a debris barrier is advocated to mitigate potential employee risks.
8.5.2 Association of periOperative Registered Nurses (AORN)
The Association of periOperative Registered Nurses’ (AORN) “Recommended Practices for Laser Safety in the Practice Setting” was first published in 1989. These broad recommended practices provide guidelines to support perioperative nurses in developing policies and procedures for the safe use of lasers in their practice setting. These guidelines represent evidence‐based practices for laser use in surgical, ambulatory, and clinic facilities.
8.6 The Joint Commission (TJC)
The Joint Commission (TJC) mandates that facilities conduct a safety assessment to determine any potential risks from hazardous energy. In the “Environment of Care” chapter, Element of Performance (E.P.) 7 EC.02.02.01, the standard does state, “The critical access hospital minimizes risks associated with selecting and using hazardous energy sources.” TJC can also refer to ANSI Z136.3‐2018 in regard to the control of laser hazards concerning the management of laser plume of smoke. The Element of Performance 9 states that critical hospitals should also minimize risks associated with disposing of hazardous gases and vapors:
“NOTE: hazardous gases and vapors include, but are not limited to: ethylene oxide and nitrous gases, vapors generated by glutaraldehyde; cauterizing equipment, such as lasers.”
8.7 Standards and Practice
Control of potential health hazards associated with the use of dental laser systems requires the adoption of appropriate safety standards and policies that are relevant to the specific laser situation. It is imperative that, for the safety of patients, physicians, hygienists, and other medical personnel, everyone involved with medical lasers understands how to safely manage each type of laser in a medical setting. Before a laser is utilized clinically, a laser safety program should be established with written policies and procedures to establish authority, responsibility, and accountability.
8.7.1 Laser Safety Officer
The laser safety officer (LSO) is a person appointed by the administration that has attained the training and education to administer a laser safety program. The LSO has the authority to suspend, restrict, or terminate a laser procedure if they determine that the hazard controls are not adequate. This does not mean the LSO must be present during every laser procedure. The LSO is responsible for the appropriate classification of lasers within the facility, hazard evaluation, control measures, procedural approval, protective equipment, maintenance of equipment, and training for all personnel associated with lasers and medical surveillance (ANSI 2018). The job description and responsibilities can be daunting; however, the LSO can utilize qualified personnel, technical support, and other resources if necessary. ANSI does state that the LSO can be a laser user, operator, or any other trained individual who is qualified to administer a laser program. ANSI Z136.3‐2018 Appendix A describes the specific duties and responsibilities:
- Safety Program. The LSO is the designated individual who has the responsibility to administer the facility’s laser safety program. Advanced training and education are required along with the skill set to knowledgeably assess the laser hazards and institute the necessary safety controls.
- Hazard Classification. The LSO assesses all laser devices to determine appropriate labeling that is FDA/CDRH required. Also, the LSO should note correct classification of each laser system and instigate safety controls for all Class 3B and 4 lasers.
- Hazard Evaluation. The LSO will conduct a hazard evaluation of all new and existing laser devices.
- Hazard Response. The LSO, or designee, will immediately communicate to the user any danger or hazards that could occur in use of a laser device.
- Control Measures. The LSO will verify that all safety controls determined by the manufacturer or established by the LSO be employed.
- Procedure Approvals. The LSO will establish, approve and enforce the facility’s policies and procedures.
- Protective Equipment. The LSO will confirm that all PPE is available and functional for all members of the laser team.
- Signs and Labels. The LSO will verify that all laser signs follow the ANSI Z136.1 and.3, Section 4.7.
- Facilities and Equipment. The LSO will approve all laser installation in accordance with the manufacturer’s safety information. Any modifications will be reviewed and documented by the LSO. Required servicing and preventative maintenance will be performed by qualified technicians per manufacturer’s protocol.
- Training. The LSO confirms that the required laser safety education and training is provided to all members of the laser team including the laser user, operators, student, technicians, hygienist, and other ancillary staff. Records will be maintained.
- Records. The LSO will verify that all national, state, and local required records are maintained along with facility audits and policies and procedures.
8.8 Hazard Evaluation and Control Measures
Hazard evaluation is influenced by various factors of the laser system being utilized. The classification of the laser and the wavelength of the laser may also assist in defining the necessary control measures to be incorporated into the safety program. These factors affect which safety controls need to be incorporated into the laser safety program and implemented into practice. Control measures are those procedures or methods implemented to minimize hazards associated with a particular laser when it is in the operational mode. Control measures may be influenced by the ability of the laser energy to injure, the environment in which the laser will be activated, personnel that may use or be exposed within the nominal hazard zone (NHZ), the delivery systems, and the nonbeam hazards associated with the specific laser. Ancillary hazards create the potential for significant injuries to occur. Injuries, including death, may occur during testing of laser equipment, during electrical equipment checks and servicing, from fires, explosions, and even embolisms.
8.9 Administrative Controls
Administrative controls are those methods or procedures specifying explicit criteria that determine the implementation of engineering controls or work practices for personnel protection. Standard operating procedures (SOP’s) are established from institutional policies and procedures. Safety controls, maintenance, and service, as well as the function of the laser, should be incorporated into the facilities SOPs. SOP’s may also include documentation requirements for pre‐procedure safety checklists, and intraprocedural laser operation and safety. The LSO is responsible for the execution of the SOP’s.
8.10 Procedural and Equipment Controls
Engineering and procedural controls are determined by the LSO and must be implemented when appropriate to circumvent potential hazards. Procedural controls require adherence to written SOP’s to ensure the safety of all personnel working in the region of lasers. SOP’s should provide for operational guidelines, emergency shut‐off mechanisms, stand‐by functions, use of low reflective materials near the laser beam path, and storage.
Operational guidelines should require switches, whether foot pedal or finger trigger, which control the laser energy be guarded to prevent accidental activation. This may necessitate one foot pedal access for the individual controlling the delivery device to prevent inadvertent activation of the laser (Castelluccio 2012). Accessory attachments to lasers must also be compatible with the laser safety guidelines. This includes laser filters on operating microscopes that protect the operator at the binocular viewing tube and through the accessory viewing tubes.
Lasers should be placed in the stand‐by mode when the laser is on but not being fired, or when the user is no longer in control of the delivery device, to prevent accidental discharge. When not in use, storage of the laser and/or disabling of the laser is necessary to prevent inadvertent activation of the laser by nonauthorized personnel. Lasers should be stored in secured areas.
Nonreflective instruments (dull, anodized, or matte‐finished) should be used in or near the laser beam to defocus or disperse the laser beam (Fencl 2017). Appropriate backstops or guards should be used to prevent the laser beam from striking normal tissue, nontargeted teeth, or tissues.
8.11 Laser Treatment Controlled Area
The nominal hazard zone (NHZ) is the space in which the level of the direct, reflected, or scattered radiation used during the normal laser operation exceeds the applicable maximum permissible exposure (MPE) (Spratt et al. 2012). An NHZ should be identified by the LSO to prevent unintentional exposure to the laser beam. Determination of the NHZ should take into consideration information gathered from the manufacturer’s labeling, by analysis, to radiation transmission of the beam and the potential for equipment failure. The NHZ is usually contained within the room but may extend through open doors or transparent windows, depending on the type of laser used. It is the LSO’s responsibility to define the NHZ and ensure that the proper safety practices are adhered to in the NHZ.
The appropriate warning signs posted at every entryway into the laser treatment–controlled area should define the NHZ (Figures ). The symbols and wording on the warning signs should be specific for the type of laser used and designed according to the information described in the ANSI standard for the Safe Use of Lasers in Health Care Facilities. New signs should be compliant with the ANSI Z535.2 even though older signs will be grandfathered in.
Figure 8.1 ANSI Z535.2 new laser signs.
Source: Rockwell Laser Industries (RLI).
Figure 8.2 ANSI Z535.2 new sign example.
Source: Rockwell Laser Industries (RLI).
Figure 8.3 ANSI Z136.12014 grandfathered sign.
Source: Vangie Dennis.
Windows and viewing areas should be limited because the NHZ may reach beyond the room in which the laser is in use. Additional safety controls, such as closing doors and covering windows with applicable filters or barriers or restricting traffic, may need to be implemented dependent on the laser used. Screens, curtains, or a blocking barrier may be placed near entryways to avert laser radiation (Figures 8.4 and 8.5).
Only authorized persons (including patients), approved by the laser safety officer, should be in the vicinity of the NHZ. Only authorized laser operators who have been delegated specific responsibilities by the laser safety officer may operate a laser. An authorized laser operator is a person trained in laser safety and approved by the facility to operate the laser. This person is responsible for the safety of the equipment and the treatment environment in the NHZ. They must remain at the laser control while the laser is in use. Their responsibilities include:
Figure 8.4 Example of occlusive tested laser window covers.
Source: Vangie Dennis.
Figure 8.5 Example of occlusive tested laser covers.
Source: Patti Owens.
- Assessment of the procedure needs including anesthesia needs, type of laser, and accessory equipment,
- Equipment checks prior to use including accessories, operation, and safety equipment to ensure safe working conditions,
- Safety controls for all personnel (including the patient) in the treatment area, such as wearing appropriate eyewear,
- Appropriate signage displayed with the appropriate laser protective eyewear (LPE),
- Setting the laser wattage and exposure appropriately and monitoring activation of the laser and observation of team members for breaks in safety,
- Completing a safety checklist and laser log.
All healthcare personnel in the vicinity of the NHZ should be trained in the implementation of all laser safety precautions to avoid inadvertent exposure to laser hazards. All personnel, including the patient, within the NHZ should use appropriate PPE.
8.12 Maintenance and Service
Preventative maintenance should be done every six months. Only properly educated, trained, and approved technicians should be allowed to work on the laser or handle the electrical components (Takac and Stojanović 1999). Thorough documentation of all fault codes, equipment malfunctions, technical support, and servicing needs to be conducted and maintained for audits and future reference.
8.13 Beam Hazards
8.13.1 Eye Protection
Patient eyes should be protected when in the NHZ. Everyone in the NHZ should wear appropriate eyewear approved by the laser safety officer (Figure 8.6). The eye is the organ that is most susceptible to laser injury. The optics of the eye can concentrate and focus laser light at wavelengths ranging from 400 to 1400 nm on the retina, which increases the potential ocular hazard. Ultraviolet and far‐infrared wavelength regions (outside 400–1400 nm) principally produce corneal effects. Also, laser radiation at certain wavelengths may cause damage to the lens of the eye (AORN Recommended Practices 2017). Appropriate laser safety eyewear filters out the hazardous wavelength of laser radiation (Figures 8.7 and 8.8). In addition to direct exposure from misdirected and damaged fibers, scattered, diffused, and reflected laser beams can cause eye injuries. LPE for the laser staff may include laser goggles, laser glasses with side shields, and prescription glasses with special filters or coatings.
The patient’s eyes and eyelids should be protected from the laser beam by appropriate methods when the eyes are in the NHZ. Protective methods may include wet eye pads, laser protective eyewear, or laser metal occlusive eye shields (Figures ). Metal FDA‐approved and tested corneoscleral eye shields may be necessary when the laser treatment is performed around the ocular ridge, corneal adnexa, and on the eyelids. Best practices indicate the use of water‐based anesthetic drops and lubricant. Corneoscleral shields should be selected based on the patient’s ocular size, should be inserted and removed by a trained professional to prevent corneal abrasions, and should be sterilized in between use per manufacturer’s instructions for use (IFU).
All personnel in the NHZ should wear protective eyewear that is labeled with the appropriate optical density and wavelength while the laser is in use. Ocular hazards may transpire during operational pretesting of the laser to confirm beam alignment and calibration. One should never look directly into the beam. Most LPE is tested for an indirect or reflected exposure. Potential for ocular hazards is also present during fiberoptic procedures as a result of the fiber becoming disconnected or breaking. Both instances also require protective eyewear to be utilized to prevent exposure of the eye. Protective eyewear should be available outside the room near the posted warning signs designating the specific type of laser in use. For optimal protection, inspect eyewear for pitting, cracking, discoloration, coating damage, frame condition, and light leaks. If any of these are present, the eyewear is considered inadequate for eye protection and should be discarded.
Figure 8.6 Appropriate eye protection (goggles) specific for different wavelengths.
Source: Vangie Dennis.
Figure 8.7 Laser protective eyewear (LPE).
Source: Innovative Optics.
Figure 8.8 Example of laser wavelength and O.D. imprinted on eyewear.
Source: Patti Owens.
Figure 8.9 Example of occlusive metal laser eyewear.
Source: Vangie Dennis.
Figure 8.10 Example of adhesive laser protective eyewear.
Source: Rockwell Laser Industries (RLI).
Figure 8.11 Example of corneoscleral patient eye shields.
Source: Vangie Dennis.
8.13.2 Skin Protection
Whenever there is a potential hazard of thermal burns from high‐powered lasers, all persons in the laser treatment area should be protected from the laser beam exposures to their skin and other nontargeted tissues. Overexposure to ultraviolet radiation can lead to skin sensitivities or even burns from direct or reflected laser energy. Surgical gloves, tightly woven fabrics, and flame‐retardant material, dependent of the laser being utilized, may provide skin protection. Protection of exposed tissues around the operative site may be accomplished by covering the areas with saline‐saturated or water‐saturated, fire/flame‐retardant materials (e.g. towels, sponges, drapes, fabrics). These materials must remain moist to absorb or disperse the energy of the laser beam. Polypropylene or plastic drapes can melt if a laser beam strikes them and woven or nonwoven fabrics can be ignited. Laser handpieces or fiber tips should be placed on a moistened surface to prevent a fire from the hot tip or shatter of the tip if placed on a cold surface.
8.14 Laser Safety and Training Programs
A laser safety program establishes and maintains policies and procedures to ensure control of laser hazards. Laser safety programs policies and procedures should include, but are not limited to, the following:
- LSO guidelines defining the authority and responsibility for evaluation and control of laser hazards. A laser committee may need to be developed when increased laser usage necessitates maintaining enforcement of SOP’s.
- Criteria and education for procedures for all personnel working in a NHZ. All personnel working with lasers should attend laser safety education courses periodically.
- Credentialing and clinical practice privileges of the medical staff are the facility’s responsibilities. Credentialing should be for specific laser procedures with specific laser types.
- Implementation of laser hazard control measures.
- A continuous quality improvement program to include appropriate use and maintenance of equipment, management, and reporting of accidents and well as prevention.
A laser education program for personnel working on or around lasers, for a facilities specific laser(s) and for specific to the procedures being performed in the facility, must be implemented. The program must comply with applicable standards and regulations covering all procedures necessary to provide a safe environment. Personnel should demonstrate and complete competency skills periodically.
8.15 Medical Surveillance
Medical surveillance for all class 3b and class 4 laser users exposed to laser radiation in the NHZ should be performed when abnormal exposures have occurred. Surveillance is specific to the personnel category and the known risks associated with the particular laser operated. Personnel categories are broken into laser personnel who routinely work in the NHZ and incidental personnel who are unlikely to be exposed to laser energy (e.g. custodial, supervisory, clerical). Surveillance may be required to assess a baseline level of visual performance, pre‐employment, to assist in the evaluation of laser damage in the case of inadvertent exposure to the eye. Surveillance can also identify those individuals who may be at risk from ultraviolet hazards, specifically to the skin. Laser accidents must be documented to define the need for further evaluation of the injured person. Suspected exposures and potential injuries from retinal hazardous laser wavelengths (400–1400 nm) should be followed up by an ophthalmologist examination within 48 hours postaccident.
8.16 Nonbeam Hazards
Hazards other than directly related to exposure to the laser (e.g. eye, skin, and other tissues) are known as nonbeam hazards. Potential hazards related to nonbeam hazards are diverse, and the LSO must determine the appropriate control methods to be implemented. Evaluations of the hazards may necessitate the need to enlist the assistance of safety and/or industrial hygiene personnel from OSHA.
8.17 Electrical Hazards
Lasers contain high‐voltage electrical circuits that may lead to shock, electrocution, or fire. Injuries from these types of hazards are some of the leading causes of laser‐related accidents and deaths. Potential electrical hazards from damaged electrical cords, faulty grounding, lack of compliance with training programs, and inadequate or inappropriate use of lockout/tagout procedures can be prevented by adherence to SOP’s of the facility. Visual inspection of the laser including electrical, plumbing, accessory equipment, delivery systems, gas supply, and sterile draping prior to use may prevent injuries from occurring. Observance of general electrical safety (e.g. no fluids placed on or near lasers, extension cords not used to power lasers) will also support the maintenance of safety.
Most medical lasers also require sophisticated cooling systems involving a coolant and fans. Do follow manufacturer’s IFU for replacing coolant, if necessary, and keep the lasers at distance from any walls or obstruction that would prevent cooling ventilation to occur.
8.18 Smoke Plume
Vaporization of tissues may release toxic gases (e.g. acetone, isopropanol, toluene, formaldehyde, metal fumes, and cyanide), noxious organic compounds, and cellular nanoparticles, including carcinogens and viruses. This laser plume contains water, carbonized particles, mutated deoxyribonucleic acid (DNA), and intact cells. At certain concentrations, ocular, upper respiratory tract irritation, and unpleasant odors may transpire. These substances should not be inhaled, thereby, initiating the need for some type of smoke evacuation system to be utilized to prevent personnel and the patient from inhaling plume. Removal of plume will also enhance the visualization of the dental treatment site and may prevent the laser beam from potentially being reflected.
Smoke plume inhalation should be reduced to a minimum by utilizing multiple controls. These controls may include the use of high‐filtration masks, wall suction units with in‐line filters, and smoke evacuators (Figure 8.12). High‐filtration or N‐95 masks should be used in conjunction with other controls and not as a sole means for protection. These masks should be tight fitting and filter particles as small as 0.1 μm. Wall suction systems may be used when the generation of a minimal amount of plume is expected, such as laparoscopic cases. Wall suctions generate low suction rates and are designed for fluids, thus an in‐line filter should be used to collect particulate matter. A mechanical smoke evacuator or suction with a high‐efficiency ultra‐low penetrating air filter (ULPA), having filtration of particles at 0.12 μm at 99.999% efficacy, should be used when a large amounts of laser plume is expected. These systems should be turned on simultaneously with the activation of the laser energy and placed as close as possible to the laser site. Standard precautions (gloves and mask) should be taken when using lasers, as well as when handling contaminated filters due to the amount of potential generated contaminants.
Figure 8.12 Example of portable plume evacuator with support clamp.
Source: Patti Owens.
8.19 Fire and Explosion Hazards
All persons in the laser treatment area should be protected from flammability hazards associated with laser usage. Fire is a potential hazard that can have devastating consequences. Laser energy can ignite flammable liquids, solids, and gases. A fire occurring with these types of materials most often materializes outside the patient, but fires can ignite with materials in the patient. Becoming aware of the safeguards and adherence to them can protect the patient as well as healthcare personnel.
Personnel should be aware of the items that have a potential for causing fire, burns, or explosions. These may include clothing, teeth protectors, drapes, hair, endotracheal tubes, paper or gauze materials, gases (e.g. oxygen, methane, anesthetic gases), and flammable liquids or ointments (e.g. skin prep solutions, oil‐based lubricants). Water or saline and fire extinguishers should be readily available where lasers are used. Any compound or solution containing alcohol (e.g. Hibiclens, Hibitane, tape removers, degreasers, benzoin, tinctures, etc.) can ignite from contact with laser energy. Alcohol vapors should not be allowed to accumulate under drapes or clothing. Overheating of iodoforms, that is to pool on or around the skin, or aerosolized Betadine can lead to flash fires when laser energy is utilized.
Oxygen concentration in the room should be kept to a minimum. The anesthesia provider should be aware of the hazards of oxygen leaking from around a patient’s face mask or nasal cannula. They should be prepared to turn off the free flow of oxygen during laser activation. Various 50% nitrous and 50% oxygen devices are now being used for pain control during dental procedures. Extreme care needs to be taken that the laser is not activated while the patient is inhaling on the mouthpiece. Remember, nitrous with oxygen can potentiate an ignition! The mouthpiece needs to be removed from the laser site during laser activation.
8.20 Shared Airway Procedures
Guidelines to minimize the risks associated with lasers and other energy modalities should be incorporated into the dental team’s practices. There are various types of laser‐dedicated endotracheal tubes. The type of laser wavelength utilized dictates the brand of endotracheal tube used. Some tubes have FDA clearances for specific wavelengths of lasers. The red rusch reusable tube wrapped in the 3 m foil tape is not an acceptable laser tube and is not an FDA approved tube. This tube is an evolved practice for which there are initial articles published in the medical literature stating this is an acceptable tube in the beginning of laser ENT airway applications. However, with the advent of new FDA‐approved laser tubes for specific wavelengths, this wrapped tube should NEVER be used. The PVC endotracheal tube is contraindicated with laser airway procedures when the tube is in direct contact with the laser beam. PVC material is very flammable, and the by‐products are hydrochloric gas and, in the presence of fluid, hydrochloric acid. There are no laser resistant tubes presently on the market. All tubes under pressure are explosive.
Considerations should be taken when choosing the appropriate anesthetic agent. No one anesthetic technique is used to the exclusion of others. Helium and compressed air are acceptable gases to use in laser procedures. Helium is a less dense gas and has the ability to flow through compromised airways easier than compressed air. Helium will also retard burning, but the risks of delivering hypoxic levels can be a problem. Pulse oximetry should always be utilized with helium delivery. Nitrous oxide is contraindicated in upper airway laser surgery. Nitrous oxide, in the presence of oxygen, will present as if 100% oxygen is being delivered. The FIO2 of the oxygen range should be no higher than 30%. Above the 30% range supports combustion.
The cuff of the endotracheal tube should be instilled with normal saline or water and methylene blue dye. The saline or water will serve as an extinguisher and the methylene blue dye as an indicator the cuff has been breached. The endotracheal tube cuff is hit 2% of the time even when lasers are utilized by the best technicians.
Areas of the patient’s face accessible to the laser should be protected from stray beams. The patient’s eyes should be covered with wet sponges or laser conformers as indicated by the surgical procedure. Water‐soluble lubricant is indicated if a laser is used. Petroleum‐based lubricant is flammable and, therefore, contraindicated.
Before any laser airway procedure, staff should familiarize themselves with the procedural steps to managing an airway fire. The steps are as follows:
- Stop the gas flow to the tube: Disconnection of the breathing circuit is the quickest method of stopping the gas flow.
- Extinguish the fire with water/saline. The operating room staff and anesthesia should have water/saline readily available on the operating room back table and anesthesia cart. Removing the tube without extinguishing the fire will allow the tube to continue to burn on extubation.
- Access of the bronchoscopes and trach trays should be readily available. The location of the instruments should be established before any airway procedure. Failure to remove any pieces of the tube will allow the tube to continue to burn in the patient.
During head and neck surgeries, the patient is mechanically ventilated in the majority of the procedures. If precautionary protocols are not followed and instantaneous action not taken if an airway fire occurs, hot gases can be forced deep into the lungs, causing extensive injuries. Seconds of indecision or confusion can cause irreparable damage or death to the patient. The avoidance, recognition, and management of airway procedures, as well as the collaborative communication between the operating team, is essential in increasing patient safety and improved care.
8.21 Conclusion
Lasers are a remarkable tool and are becoming an accepted mode of operation. The laser’s limits are endless and have been an asset in industry, armed forces, and medicine. Seldom in our century has a new technology brought so many benefits and enhanced our lives. It’s important to keep in mind that technology such as the laser has an enormous value and has made a difference in our healthcare arena. That it was even discovered says so much about the depth of human scientific and creative potential. How we ultimately use it says much about our human character. L. Beecher said that no great advance has ever been made in science, politics, and religion without controversy, but technology leads to the further growth of technology.
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