Chapter 72. Anesthesia for Laser Surgery

• Laser = light amplification by stimulated emission of radiation
• Focalized high energy → instant coagulation → reduced bleeding, sparing of healthy tissues

Vocal cord surgery:

• Complete NMB of vocal cords
• Inhibition of pharyngeal reflexes
• Decrease secretions (glycopyrrolate 0.2–0.4 mg IV)
• If intubation, prefer special laser ETT (metal-coated, double cuff, small diameter); inflate cuff(s) with colored saline
• If no intubation, typically transglottic jet ventilation

Tissue injury:

• Iatrogenic injury to patient can be caused by laser:
  • Pneumothorax, blood vessel puncture, hollow viscus (trachea) rupture
  • Dental injury
• Eye injury is of special concern, to both patient and health care provider:
  • Window to OR door should be covered
  • Everyone in OR (including patient) should wear appropriate wraparound goggles (Table below on Appropriate Eye Protection)
  • Place wet eye pads on taped patient’s eyes and under goggles

Venous gas embolus:

• Gas is often used to cool laser probe tip
• Gas embolus can occur (especially during laparoscopic uterine surgery):
  • Saline insufflation can be used, but fluid overload is possible
• Watch end-tidal CO2 closely. If embolus suspected, cease use of laser, support hemodynamics until embolus resolves

Laser plume:

• Vaporized tissue can be inhaled by operating room personnel
• In theory, possible vector of infection (viruses) or malignant cells
• Consider use of high-efficiency filtration masks

Airway fire (ETT ignition):

• Prevention of airway fire:
  • Limit FiO2 to lowest amount compatible with adequate patient oxygenation (21–40%)
  • Avoid N2O (supports combustion)
  • Use specially designed tube (if unavailable, wrap tube in metal foil)
  • Encourage placement of moistened pledgets around cuff by surgeons
  • Fill cuff with methylene blue–colored saline to provide surgeons with visible warning of cuff puncture
• Treatment of airway fire:
  • Cease use of laser immediately
  • Immediately disconnect tube from circuit. This should extinguish fire quickly:
    • Extubate as soon as the fire is extinguished. If fire still persists after circuit disconnection, pour saline in mouth
  • Place tube in water after extubation
  • Reintubate patient:
    • Airway damage may increase difficulty of intubation. Consider use of difficult airway equipment. Have surgeons prepare for tracheostomy if necessary
  • Assess lung damage with bronchoscopy. Keep patient intubated postoperatively. Monitor arterial blood gases, chest radiograph; assess airway for swelling (consider steroid course)