Airway For Laser Surgery

Medical lasers are used in multiple medical procedures nowadays, including ophthalmic, dermatologic, plastic, and dental surgeries, as well as more invasive intraabdominal, cardiothoracic, neurologic, gynecologic, and urologic procedures. Lasers provide a source of focused, coherent light capable of transmitting intense energy to a precise location. This is used to destruct (burn) or cut tissues (due to photo-acoustic shock wave effects) and to provide hemostasis (highly pigmented tissues, like blood, selectively absorb laser light). Importantly, lasers can ignite flammable materials present in the operating field, such as endotracheal tubes, sponges, and catheters. They also pose a risk of eye injury (both to the patient and operating room personnel), laser plume, electrical tripping, and release of chemical contaminants. Multiple media can be energized to create a laser, and the choice of such depends on the type of procedure performed, location, and physician preference.Upper respiratory tract and tracheal surgeries are often challenging, as the airway is often compromised and manipulated, while shared by both the anesthesiologist and surgeon. The addition of laser introduces a source of ignition that is especially dangerous when supplemental oxygen is added to the inspiratory gas mixture. This dilemma is constantly discussed, and multiple techniques were developed to provide ventilation to an anesthetized patient while keeping the surgical field maximally accessible and minimizing laser-related hazards. The common ventilatory strategies include conventional endotracheal intubation, jet ventilation, intermittent apnea technique, and spontaneous breathing.Multiple methods and numerous "laser-resistant" endotracheal tubes (ETT) were designed to protect the operating field from the hazards of medical lasers. The American Society of Anesthesiology now recommends these as the default endotracheal airway during laser surgery of the respiratory tract. The cuff is the most vulnerable part of the ETT. During intubation, once the tube passes through the vocal cords, the balloon at its distal end (cuff) is inflated with air (or saline) to occlude the trachea external to the tube and thus directs all the gas flows from the ETT exclusively to the trachea, and vice versa. If the cuff is marked by a laser, it becomes compromised and can no longer seal the trachea. This leads to a gas mixture rich in oxygen and potentially flammable anesthetic gasses used to ventilate a patient that can escape to the upper airway and surgical field. A fire may be ignited during this event or subsequent use of the laser. The ETT materials (gauze, drapes, dried blood, and tissues) are the most common fuels.