SS Lasers - Fall23.pptx

Lasers Clay Freeman, DNP, CRNA Science in Anesthesia 1 Objectives Readings: Nagelhout: Chap. 15 Davis: Chap. 24 • Describe the basic mechanisms of lasers • Discuss the intrinsic risks and dangers of lasers • Describe the types of lasers, their uses and specific considerations • Evaluate various...

Lasers Clay Freeman, DNP, CRNA Science in Anesthesia 1 Objectives Readings: Nagelhout: Chap. 15 Davis: Chap. 24 • Describe the basic mechanisms of lasers • Discuss the intrinsic risks and dangers of lasers • Describe the types of lasers, their uses and specific considerations • Evaluate various anesthesia techniques and interventions necessary when lasers are in use in the OR • Detail fire risks and evaluate emergency precautions and treatments 2 Laser Principles A laser is a device that controls the way that energized atoms release photons. "Laser" is an acronym for Light Amplification by Stimulated Emission of Radiation • In Other Words: Emits thermal radiation in the form of photons/radiation/light Atoms absorb energy  Electrons get excited & move to a higher orbit  Electrons return to ground state/lower orbit & emit photons of energy (electromagnetic radiation) 3 Electromagnetic Spectrum Non-Ionizing Radiation Far Ionizing Radiation Near Laser Range 4 Laser Principles Components of a laser:  Energy Source (usually electrical)  Windows w/ Mirrors x2 • (Brewster angle)  Resonant Chamber: laser medium  Electrodes x2 (Anode & Cathode) Types of laser medium: • Gas (CO2, Argon, Excimer) • Solid-state (Nd:YAG) • Dye (liquid medium) 5 Laser Principles Laser light properties Monochromatic. It contains one specific wavelength of light (one specific color). The wavelength of light is determined by the amount of energy released when the electron drops to a lower orbit. Coherent. It is “organized”  each photon moves in step with the others. Waves peak and trough in unison Directional. A laser light has a concentrated beam. 6 Medical Utility Carbon Dioxide laser - Far-infrared wavelength. Not fiberoptic transmissible Nd-YAG laser - Neodymium-Yttrium Aluminum Garnet laser. Solid with crystalline structure. Near-infrared wavelength KTP laser – Potassium TitanylPhosphate laser. Solid-state medium. Used in neurosurgical and otolaryngologic surgeries. Green colored. Argon laser - Useful in retinal and dermatologic procedures. Gas medium. Blue-green colored. Excimer – used exclusively for retinal and LASIK surgery 7 Laser Surgery Benefits of laser surgery: microscopic precision, bloodless operative field, reduction of tissue reaction, preservation of normal tissue, and complete sterility 8 CO2 Lasers CO2 lasers provide precision cutting and coagulation Efficient tissue vaporization due to water absorption at far-infrared wavelength Frequently used for ENT surgery including: • Laryngeal tumors • Oropharyngeal tumors • Resection of tonsillar tissue • Idiopathic subglottic stenosis • Tympanoplasty • Vocal cord polyps Longer wavelength = Lower frequency = Lower energy Focused to superficial tissues 9 Nd-YAG Lasers Neodymium-Yttrium Aluminum Garnet (Nd:YAG) Shorter wavelength = Higher frequency = Higher energy Penetrates tissue deeper than CO2 • Wavelength is ~1/10th the length as compared to CO2 • Photons are poorly absorbed by water Coagulates and necrosis deeper tissues Useful in ENT surgery: • Distal airway surgery (Tracheobronchial tumor) o Provides better coagulation in vascular pathologies 10 Optical Fibers Fiber optic instruments provide a glassair boundary that energy sources may travel while avoiding complete Refraction • Navigation of energy is possible via Reflection Refracti on Reflecti on End result: Energy is transmitted through flexible quartz fibers Surgeons and proceduralists utilize these in: • Endo• Broncho- 11 Safety OR staff: • Laser in stand-by mode when not in use • Secondary light beam used to assist aiming • Monitor location of instruments and flammable materials • Laser safety goggles • Clear communication • Plan of action & designated crisis roles Patient: • Laser safety goggles • EtO2 <30% • Soaked gauze and towels in place o Where they removed at the end? • Saline tub at the ready 12 I saw the sign Warning signs outside the operating room Opaque coverings on OR windows 13 Goggles The eye is particularly sensitive to damage since the lens focuses energy toward the retina Protective eyewear is designed to filter out radiation of a specific wavelength • Minimal to no cross protection between lasers Eyewear filters block portions of the visible spectrum • Verify patient monitors can still be interpreted Protective eyewear is recommended for all personnel 14 Anesthetic Technique Analysis of malpractice claims 1985-2009 related to OR airway fire. 103 total claims 76% occurred during MAC vs 24% receiving GETA General Anaesthesia • FiO2 40% or less (21% preferable) • Avoid N2O - supports combustion • Volatile anesthetics are non-flammable • Coordination with surgeon Sedation Delivering O2 by facemask or nasal cannula requires special care  ≤ FiO2 40% • N/C < 6L/min • Monitor for drape “Air Pockets”  Coordination with surgeon 15 Airway Laser-resistant Endotracheal Tube Ignition of ETT material is especially dangerous in airway procedures • Conventional PVC can serve as a temporary fuel source Use noncombustible tubes specific for laser use • Or wrap ETT with laser foil/sleeve Smaller tubes typically used for surgical exposure • 5.5-6.5 mm tube ETT cuffs are not laser resistant and are prone to puncture  Fill ETT cuff with saline or dye • Enhances detection of cuff compromise  May be manufactured with 2 cuffs 16 Laser ETTs Laser-resistant endotracheal tubes stainless steel metal Red rubber laser resistant ETT Embossed copper foil Aluminum wrapped ETT 17 Fire Trifecta American National Standards Institute standard Z136.3 Many items can act as fuel: • Surgical towels • Drapes • Aseptic preparation solutions • Sponges • Plastic tubing (N/C, FM, That You ! ETT) • Body hair =] 18 Airway Fire Immediately suspend ventilation & stop all gas flow Extubate & Extinguish with water or saline Re-intubate patient Ventilate with high FiO2 ICU transfer & Assess airway via fiberoptics +: Administer Steroids 19 Flowchart 20 R.A.C.E for an OR fire 21 P.A.S.S. Fire extinguishers are divided into classes based on the types of fires they are best suited  Class A: paper, cloth, and plastic materials  Class B: liquids or grease are involved  Class C: electrical equipment  Best fire extinguisher for the OR is the CO2 extinguisher • Used for Class B & C fires and some Class A. 22 Smoke Plumes Smoke plume from Electrosurgery and lasers include:  Compounds known to be carcinogenic  Environmental toxins  Viable bacteria  Intact DNA from Viruses • Human papillomavirus (HPV) • Human immunodeficiency virus (HIV) Case report Documented appearance of laryngeal papillomas in a laser surgeon who previously treated several patients with anogenital condylomata. Tissue from the surgeon’s laryngeal tumors contained HPV DNA types 6 and 11, (the same viral types harbored by anogenital condylomata). Protective Strategies: The use of a smoke scavenging at the surgical site, protective filtration masks, distance from the plume 23 Additional Resources • Miller’s Anesthesia. 9th ed. Gropper, et al. Chap 70. • Anesthesia Equipment. 3rd ed. Ehrenwerth. Chap 24 24