Laser Safety

Lasers are common in ENT and opthalmic surgery. Lasers:

• Facilitate:
  • Accurate control
    Requires the guiding (red helium) laser to be zeroed accurately so it matches the site of the therapeutic beam.
  • Minimal bleeding
  • Minimal local tissue reaction
• Are a hazard to both patients and staff
  Due to risk of:
  • Eye injury
  • Burns
  • Airborne contamination
• Have controls to ensure safety
  These are classified into:
  • Engineering controls
  • Administrative controls
  • Procedural controls

Risks

Include:

• Eye injury
  Lasers cause tissue destruction by heating water. Different wavelengths cause tissue injury at different depths:
  • Long-wavelength
    CO₂ and Er:YAG lasers may burn the cornea directly.
    • Usually not permanent
    • Very painful
  • Mid-range infrared
    Ho:YAG lasers partially burn and transmit through the cornea.
    • May damage cornea as a long-wavelength laser
    • May damage the lens
  • Short wavelength
    Penetrate through water and the anterior structures of the eye.
    • May cause permanent retinal damage
• Fire and heat injury
  Energy from the laser may potentially cause:
  • Fire:
    • Dry/non-woven fabric
    • Plastic
    • Rubber
    • Alcoholic solutions
    • Tape removers
  • Chemical burns
    • Wet iodophor solutions
  • Melting
    Some equipment won’t burn, but will melt. This includes:
    • Some surgical drapes
• Airborne contamination
  High-power laser results in evaporation of cellular components; including viruses, bacteria, and mutagenic DNA. This is in addition to the standard toxic gases present in smoke.

Safety

Communication is critical and underpins all of these safety considerations

Methods include:

• Engineering Controls
  • Guarded footswitch
  • Audible and visible emission indicators
  • Stand-by control
  • Emergency shut-off
  • Beam attenuators
• Administrative controls
  • Laser Safety Officer
    Responsible for risk, and authority to force compliance with rules.
  • Laser Safety Committee
  • Formal audit process of issues
• Procedural controls
  • Eye protection
    
    • Protective eyewear worn at all times, including by the operator
      Needs to be specific to the laser in use.
  • Remove flammable substances
    
    • Use matte drapes
    • Remove cosmetics at operative site
      Hairspray, gels, mousse, nail polish.
    • Remove reflective materials from beam path
    • Use a laser resistant tube if lasering in airway
    • Non-flammable window coverings
    • All non-reflective materials should be tested or rated for laser safety
      Black colour does not imply a low reflectivity.
    • Drape non-targeted tissues in wet towels
    • Remove oxygen from target site
  • Controlled access
    
    • Identification of the room
      Signage at entries to the room.
      • Protective eyewear should be available at all entries and exits
    • All doors closed
    • All doors unlocked
  • Smoke management
    • Active capture of plume
    • Use of ultra low particulate air filters
      Required for viruses.
    • Use of protective face masks
      Usually costly and largely ineffective due to efficiency and efficacy of the sieve.
  • Active control of laser
    • Always attended whilst on
  • Water
    Available to douse fire, and team trained in its use.

Airway Safety

If lasering in the airway:

• Use a laser safe tube
  • Fill cuffs with saline
  • Silicone tubes produces a powdery silica ash
  • PVC are flammable and produce hydrogen chloride and phosgene, which cause chemical pneumonitis
• Keep FiO₂ ⩽30%
• Tube soiling ↑ risk with Nd:YAG laser

---

References

1. Smalley PJ. Laser safety: Risks, hazards, and control measures. Laser Ther. 2011;20(2):95-106. doi:10.5978/islsm.20.95