Laser Safety in Gynecologic Surgery

Introduction

Lasers focus visible and invisible energy for various purposes. The 2 most-common uses for lasers in surgery are cutting and coagulation. Lasers can involve the same concerns as any other energy source used to cut or coagulate tissue. However, lasers are more complex, as they have multiple wavelengths each with its own characteristics. Some lasers are visible and some are invisible. This article is an overview of more-common safety concerns about using lasers for surgery. Laser safety officers and others who are involved in compiling checklists and protocols need to consult the American National Standards Institute Z136.1 Safe Use of Lasers and other publications from the Laser Institute of America. ¹ *

American National Standards Institute

As noted above, the American National Standards Institute (ANSI) publishes American National Standards Institute Z136.1 Safe Use of Lasers that helps set standards for safety for use of lasers. ¹ This publication is used by industries, including medicine, the Occupational Health and Safety Administration (OSHA), the U.S. Food and Drug Administration's Center for Devices and Radiological Health, and The Joint Commission. ² Common concerns these groups have include ocular hazards, laser-generated airborne contaminants, fires, and unintended laser-beam injuries. Room signs are used to clarify the specific laser in use, including type, power level, safety glasses need, and other requirements.

Association of periOperative Registered Nurses

The Association of periOperative Registered Nurses (AORN) has recently updated its laser safety guidelines. ³ Those are currently available on eGuidelines Plus and will be published in the planned 2022 publication, Guidelines for Perioperative Practice.

Third-Party Vendors

Third-party vendors who bring laser into facilities should meet all requirements of the facilities’ laser-safety programs with oversight of laser-safety committees. Equipment documentation, including inspection, maintenance, and repairs are needed. The vendors should be credentialed and the equipment must be compliant with the facilities’ policies and procedures.^3,4

Laser Safety Officer

A laser safety officer coordinates a facility's laser-safety program, checklists, and protocols for credentialing all team members. This officer heads a laser-safety committee for administering the laser-safety program. The officer needs authority to respond to inadequate laser-hazard controls by suspending, restricting, or terminating a noncompliant laser system.^1,2,4

Checklists

Routine use of checklists, timeouts, and safety protocols for each procedure are advocated for reducing adverse outcomes. The checklist can include items such as restricting access to security codes or laser keys, calibration of the beam alignment for each procedure, placing the laser foot pedal where it cannot be confused with other foot pedals or activated by anyone other than the person using the device, keeping ancillary equipment pedals on opposite sides of a table, and locking the door. ⁴ A modifiable checklist example is available from Daggett et al. ²

Education

Laser safety can be major a concern during gynecologic surgery and other kinds of surgery. All personnel, including surgeons, need initial and ongoing education in laser and laparoscopic safety. Laser education should be oriented toward the specific laser to be used. When possible, a surgeon should do the first few cases with a preceptor who has experience with the laser equipment.

Eye Protection

Eye injuries comprise a majority of reported injuries. ² These are associated with direct-beam exposure, reflections from surgical instruments, and beam reflections from skin. Damage can occur with visible or invisible lasers. ¹

The chance of eye damage exists with all lasers, but the location varies with laser types. For nonlaser light sources, the eye's normal aversion response to strong brightness and the blink reflex protect the eyes. However, laser energy is so concentrated that protective eyewear is needed. CO₂ lasers can cut or coagulate the cornea while argon and yttrium aluminum garnet (YAG) lasers damage the retina as those beams will pass through the lens. ⁵

The different wavelengths of lasers affect different parts of the eye. The retina, cornea, or lens can be affected based on the laser's wavelength. The lens is primarily affected by acute (lenticular burns) and chronic (cataracts) injuries and may concentrate a laser beam onto the retina by a factor of 100,000. Personal protective eyewear is mandated by ANSI and OSHA for all class-3 and class-4 lasers. The protective eyewear is labeled with the wavelength and the degree of optical protection needed to match the laser being used. It is recommended that each laser be in a separate room with the appropriate protective eyewear hung outside on the door of that room for surgical personnel to use. Eye protection for patients can be the same as for surgeons, such as leaded eye shields with nonreflective surfaces, wet eye pads, opaque barrier blocks, or water-soluble eye lubricants.^1,2,4

The lenses of microscope and endoscope systems can protect the eye from a CO₂ laser beam. However, the beam from YAG, potassium titanyl phosphate, and argon lasers can be transmitted through these systems. Protective eyewear or filters attached to the lens systems are needed.

Fires

Fires can occur when an unintended target is flammable, such as endotracheal tubes, drapes, and methane gas. Care to identify these unintended targets and control activation of the laser until it is only on the intended target is needed. This is generally a matter of awareness, focus, and control of the activation device. ⁵ Fires can also be due to faulty wiring causing electrical fires inside the laser. ¹

Precautions used include fire extinguishers, fire-extinguisher blankets, water, and fire-resistant drapes. Flammable material, such as packs and drapes, should be replaced by nonflammable ones or kept wet. ²

Laser Plume

Airborne contaminants in a laser plume include chemicals, viruses, bacteria, aerosolized blood products, and nanoparticles (< 1 μm) known as ultrafine particles (UFPs). A laser plume has mutagenicity similar to cigarettes, electrosurgical surgery, and other sources of particulate smoke,^1,6 with 77% of all particles <1.1 μ capable of entering the alveoli. ⁷

The plume contains as many as 60 chemicals, including carbon monoxide, hydrocyanide, benzene, toluene, and formaldehyde. ² Several are known carcinogens, and others are environmental toxins. Viruses and bacteria may be transmitted in the plume. Human immunodeficiency virus (HIV) DNA and human papillomavirus have been found in plumes. ² Intact viral DNA of papillomavirus has been confirmed in the vapor of laser-treated verrucae as far as 8 feet from the surgical site. ⁸ The plume has caused bronchitis in laboratory settings. ⁹

Many virus particles and UFPs are <0.1 μm in size. It has been noted that neither surgical masks nor N-95 high-filtration masks can filter viral particles <0.1 μm. ² Thus, adequate suction should be used to evacuate the plume. A CO₂ laser plume can be reduced by 98.6% with proximal (1 cm) suction. This decreases to <50% at a 2-cm distance.^2,7 This is more important with open procedures and lower genital work than with a closed laparoscopy system. High-power filtered units are generally used.

Additional Concerns

A laser beam can be aimed inadvertently into a room and potentially windows. Windows in a laser-treatment area should be covered to prevent the laser beam from passing through them. Covers are specific for laser types.^1,2

Laser equipment can malfunction. This includes the shutters. Fail-safes have been designed into lasers that automatically deactivate the unit with a shutter failure. The internal capacitors can have high voltage in excess of 15,000 V and should be opened only by someone trained in maintenance of high-voltage capacitors. ⁵

Lasers are generally line-of-sight instruments that can be activated on any target, whether it is intended or accidental, just as knives can be used well or not. Unintended targets can include other tissues, instruments, and a surgeon's fingers or hands.

Carbonization is an increasing concern with low lower-density CO₂ lasers. This can interfere with recognition of endometriosis during surgery and during any subsequent surgery. ¹⁰ Moreover, sublimation of carbon occurs at >3600°C and results in thermal damage at up to 2.7 mm.^11,12

Surgical complications that occur with any energy source are hemorrhage from hilar vessels, partial tubal amputations while dissecting adhesions, need for transfusions, laparotomy for bowel lacerations due to trocars, colostomy, urinary leaks and ileus from bladder damage, and cardiac arrest with death. Uncommon complications include hypothermia (92°C) secondary to cool-intraperitoneal-lavage solutions and emphysema when dissecting from the mediastinum to the neck.^5,13

Conclusions

The safe use of surgical lasers is facilitated by checklists and safety protocols to cover the laser safety program. Organizations such as the American National Standards Institute, the Laser Institute of America, and the Association of periOperative Registered Nurses provide guidance in setting up protocols for education, ocular hazards, airborne contaminants, fires, unintended laser beam injuries, and general surgical complications.