Laser Safety

Purpose

This document provides guidance to the perioperative team on the safe use of lasers, the roles and responsibilities of personnel, and the educational requirements for personnel involved with use of a laser system for medical procedures.

The laser system consists of the laser, a delivery system that directs the output of the laser, a power supply with control and calibration functions, the mechanical housing, and the medium.¹  The light produced by a laser is a portion of the electromagnetic spectrum and may be infrared, visible, or ultraviolet. The type of light produced depends on the type of diode²  or the material or medium inside the laser (eg, solid, liquid, gas).^3,4  The solid medium may be yttrium aluminum garnet (YAG) with neodymium (Nd), or it may be doped with holmium. The liquid medium is usually a dye, and the gas may be carbon dioxide (CO₂) or excimer.⁴  The medium that is present is frequently used as a descriptor of the laser system (eg, Nd:YAG, CO₂).

The word “laser” is an acronym for light amplification by stimulated emission of radiation. Lasers are classified as 1, 1C, 1M, 2, 2M, 3R, 3B, or 4, which is based on the accessible laser radiation.^5,6  The majority of the lasers used in health care facilities are class 3R, 3B, and 4¹ :

• Class 3R laser systems present a low risk for injury, although the eye may be injured if it is focused and stable and the beam enters the eye directly or via specular reflection.¹  The diffuse reflection is usually not a hazard. Class 3R lasers are not hazardous to the skin and do not normally present a fire hazard.¹ 

• Class 3B laser systems may be hazardous when the beam enters the eye directly or via specular reflection, but they do not normally cause a diffuse reflection or act as an ignition source.¹  The diffuse reflection is usually not a hazard. Class 3B lasers are not hazardous to the skin and do not normally present a fire hazard.¹ 

• Class 4 laser systems are hazardous to the skin and to the eye when the beam enters the eye directly. They may be hazardous when the beam enters the eye via a diffuse reflection. Class 4 lasers also can present a fire hazard and may produce laser-generated air contaminants and hazardous plasma radiation.¹ 

Lasers are used in a wide variety of settings (eg, offices, clinics, ambulatory surgery centers, hospitals) and procedures, including gynecologic, orthopedic, dermatologic, ophthalmologic, urologic, neurosurgical, cardiovascular, otolaryngologic, and cosmetic procedures.^1,7-13 

When the laser is activated, the beam can be reflected, scattered, transmitted, or absorbed. Reflection can be either diffuse or specular. The scattered beam may be absorbed or it may be backscattered. Absorption results in thermal damage to the tissue. The amount of thermal damage depends on the laser wavelength, beam fluence, radiance, chromophore consistency, water content of the tissue, the length of time of the application, and the temperature to which the tissue is heated.^5,12  The effects of the laser on the target tissue may be either a photothermal interaction, a photochemical interaction, or a photomechanical/ photoacoustic interaction.^1,5,14 

The patient may experience various adverse effects or complications from laser treatment, depending on the area being treated. Adverse effects or complications include pain, edema, bleeding, purpura, infection, air embolism, hemorrhage, surgical emphysema, cellular damage around the area of laser impingement, skin pigmentation, scarring, reticulate erythema, ocular complications, and burns.^7,10,15-20  In a review of the Manufacturer and User Facility Device Experience (MAUDE) database, Zelickson et al²¹  found 494 adverse events caused by the use of various lasers in dermatological settings between 2007 and 2011. The reported injuries to patients included blistering, burns, scarring, pigmentation damage, and infection.

The effects of the laser are considered beneficial if the laser beam reaches the intended target, but if it reaches a non-intended target, the effect can be an injury, and the beam is then considered hazardous. The hazards are generally categorized as beam hazards or non-beam hazards. Beam hazards can cause ocular and cutaneous injury. Non-beam hazards originate within the laser device itself or are created by the laser beam’s interaction with materials in the surgical environment; these include laser plume hazards, fire hazards, and electrical hazards inherent in a high-voltage system.^22-24  The hazards to patients and personnel can be minimized by the use of personal protective equipment (PPE) and engineering, administrative, procedural, and special controls (eg, signage).^6,25 

Unintentional exposure to the laser beam may result in injuries to the eyes or the skin of the patient or health care personnel.^4,6,12,26  The type of injury will vary based on the classification of the laser.^4,26 

Another hazard associated with the use of a laser is fire.²⁷  Smith and Roy²⁸  surveyed 8,523 members of the American Academy of Otolaryngology—Head and Neck Surgery to obtain information regarding the characteristics and the frequency of OR fires in otolaryngology. Eighty-eight of the 349 surgeons who responded to the survey reported having witnessed at least one OR fire during their career. For the total of 106 fires reported, the ignition source was an electrosurgical unit (59%), a laser (32%), or a light cord (7%). In an analysis of 5,297 surgical malpractice claims from 1985 to 2009 in the American Society of Anesthesiologists Closed Claims Database, Mehta et al²⁹  found 103 claims related to surgical fires. Lasers were found to be the ignition source in nine of the claims. The remaining sources of ignition were electrosurgical devices (n = 93) and a defibrillator (n = 1).

A limitation of the evidence is that randomized controlled trials related to laser injury prevention may expose patients to harm and, as such, would not be ethical. A limited number of other types of studies have been conducted and contribute valuable knowledge to the field. However, interpretation of these studies is limited by the nature of this type of research, which can only show association among study variables and cannot determine causation. Because of a lack of research on interventions to prevent injury from the use of lasers, much of the available evidence is based on generally accepted practices and expert opinion.

The following topics are outside the scope of this document:

• general fire safety (See the AORN Guideline for a Safe Environment of Care³⁰ ),

• surgical smoke safety (See the AORN Guideline for Surgical Smoke Safety³¹ ),

• credentialing and educational requirements for physicians and allied health practitioners,

• laser use in the dental setting,

• the selection of lasers,

• the selection of a method of ventilation, and

• power and energy settings.

Evidence Review

A medical librarian with a perioperative background conducted a systematic search of the databases Ovid MEDLINE®, Ovid Embase®, EBSCO CINAHL®, and the Cochrane Database of Systematic Reviews. The search was limited to literature published in English from January 2009 through March 2019. At the time of the initial search, weekly alerts were created on the topics included in that search. Results from these alerts were provided to the lead author until May 2019. The lead author requested additional articles that either did not fit the original search criteria or were discovered during the evidence appraisal process. The lead author and the medical librarian also identified relevant guidelines from government agencies, professional organizations, and standards-setting bodies.

Search terms included ablation techniques, access control, accident prevention, accidental activation, airway fires, airway laser, airway stents, anesthesia, awake patients, balloon dilation, bronchoscopy, burns, catheter ablation, CO₂laser, cosmetic techniques, diode laser, distribution of safety glasses, documentation, double lumen tube, durable medical equipment, electric power supplies, electric wiring, electrical equipment and supplies, endobronchial surgery, endoscopy, endotracheal tube, equipment and supplies (hospital), equipment contamination, equipment failure, equipment failure analysis, equipment safety, eye burns, eye injuries, eye protective devices, filtering criteria, fire extinguisher, fire management, fire safety, fires, goggles, intraoperative complications, laryngeal disease, laryngeal neoplasms, laser ablation, laser audit, laser calibration, laser debulking, laser documentation, laser fiber, laser hazard analysis, laser hazards, laser knife, laser malfunction, laser operator, laser photoablation, laser power setting, laser safety, laser safety audit, laser safety committee, laser safety education, laser safety officer, laser safety program, laser scalpel, laser surgery, laser therapy, laser treatment area, laser vaporization, laser-related burns, lasers, misdirection, nonablative laser treatment, normal hazard zone, nurses, occupational exposure, occupational hazards, occupational injuries, occupational safety, ocular adnexa, ocular laser injuries, operative microscope, patient safety, perioperative nursing, personal protective equipment, postoperative complications, power sources and settings, preoperative care, protective clothing, pulsed laser, pulsed tissue ablation, rigid bronchoscopy, risk management, safety glasses, safety lenses, sedated patients, shared airway procedures, shared airway safety, surgical equipment, surgical fires, and veins.

Included were research and non-research literature in English, complete publications, and publications with dates within the time restriction when available. Historical studies also were included. Excluded were non-peer-reviewed publications and older evidence within the time restriction when more recent evidence was available. Editorials, news items, and other brief items were excluded. Low-quality evidence was excluded when higher-quality evidence was available, and literature outside the time restriction was excluded when literature within the time restriction was available (Figure 1).

Figure 1

Flow Diagram of Literature Search Results

Adapted from Moher D, Liberati A, Tetzlaff J, Atman DG; The PRISMA Group. Preferred reporting items for systematic reviews and meta-analyses: The PRISMA Statement. PLoS Med. 2009;6(6):e1000097.

Articles identified in the search were provided to the project team for evaluation. The team consisted of the lead author and one evidence appraiser. The lead author and the evidence appraiser reviewed and critically appraised each article using the AORN Research or Non-Research Evidence Appraisal Tools as appropriate. A second appraiser was consulted in the event of a disagreement between the lead author and the primary evidence appraiser. The literature was independently evaluated and appraised according to the strength and quality of the evidence. Each article was then assigned an appraisal score. The appraisal score is noted in brackets after each reference as applicable.

Each recommendation rating is based on a synthesis of the collective evidence, a benefit-harm assessment, and consideration of resource use. The strength of the recommendation was determined using the AORN Evidence Rating Model and the quality and consistency of the evidence supporting a recommendation. The recommendation strength rating is noted in brackets after each recommendation.

Note: The evidence summary table is available at http://www.aorn.org/evidencetables/.

Editor’s note: MEDLINE is a registered trademark of the US National Library of Medicine’s Medical Literature Analysis and Retrieval System, Bethesda, MD. Embase is a registered trademark of Elsevier B.V., Amsterdam, The Netherlands. CINAHL, Cumulative Index to Nursing and Allied Health Literature, is a registered trademark of EBSCO Industries, Birmingham, AL.