1. Anesthesia for Laser Surgery

2. LASER Light Amplification of the Stimulated Emission of Radiation
Intense controlled beam of light
Characteristics :
- coherence (one phase)
- collimation ( parallel direction)
- Monochromaticity (same wavelength)

3. Apparatus Lasing medium External source of energy - Pumping
Unstable potential energy – Population reversal
Release of quantum of energy – photons of light
Reflected through a long resonator
Exit through a mirror

5. Effect of Laser Thermal effects depend on - Energy density - Flux
Temperature

6. Thermal effect on tissues
Below 55ºc slight destructive shrinking
Above 55ºc welding of cell walls
60ºc early denaturation of cell protiens
100ºc cell water boils and vaporises

7. Types of Lasers Argon gas - ophthalmic photocoagulation, skin
lesions, angioplasty, stapedectomy
CO2 gas cutting & vaporising
Liquid dyes - angioplasty
Excimer gas - angioplasty, radial keratotomy
Krypton gas - photocoagulation
Nd-YAG solid – coagulation, heating of tissues for
haemostasis
erbium:YAG
Thulium
Holmium:YAG (Ho:YAG)

8. CO2 Lasers HeNe used as an aiming co-axial laser
Laryngeal laser surgery (e.g., laryngeal condylomata, papilloma’s and tumors)
Long wave length (10.6 um)
Total absorption in the first few cell layers
Accurate vaporization with minimal peripheral injury
Best precision (0.2mm)
Cannot be used through a fiberoptic scope
Errant beams can result in corneal damage
Can be stopped with any clear lens material

9. Nd-YAG lasers Neodymium-yttrium aluminum garnet (Nd-YAG) Invisible
Coagulation of hemorrhagic lesions (necrotic respiratory tumors and GI varices)
Wave length of 1.06 um
Penetrate tissues causing deep damage with more thermocoagulation and less vaporization
Can be used through a fiberoptic scope
Penetration is variable with a greater potential for damage to normal tissue

10. Holmium:YAG (Ho:YAG)
Precise cutting with minimal damage to adjacent tissue
Fiberoptic delivery (which is ideal for endoscopic use)
Treats tissue in a liquid-filled environment (e.g., saline, blood).

11. Argon Laser Blue-green light Short wavelength of 0.6 um
Primary use for pigmented structures (hemangiomas, port wine stains, retinal surgery)

12. Diode laser 980-nm wavelength Fiberoptic delivery system
Tissue-cutting effect comparable to CO2 laser
Coagulation effect comparable argon laser
Higher degree of absorption by tissue than Nd:YAG laser
Large (up to 10 mm) penetration depth in biologic tissue
Ideal for photocoagulation

13. Advantages of laser surgery
Precise
Selective absorption
Minimal pain, scarring and edema
Remote alteration of tissues
Easy transmission through endoscopes

14. Applications Laparoscopy Endoscopy Thoracic surgery Ophthalmology
Gynecology
Plastic surgery
Urology
Neurosurgery
ENT

15. Laser in Urology Nd:YAG, Ho:YAG, KTP, diode sources
Lasers for benign and neoplastic tissue coagulation and vaporization
- Prostatectomy
- Transitional cell carcinoma of bladder,
ureter, and renal pelvis
- Renal, adrenal. genital and urethral tumors
Laser incision of ureteropelvic junction, ureter, and urethral strictures
Laser lithotripsy

16. General safety considerations
Patient
Protection of eyes, nose, moustache/ beard
No eye ointments / No metal eye cups
No plastics
Cloth adhesive tape/ Wet with high porosity
Avoid tincture benzoin
Tissue cleansing agents should be wiped off

17. General safety considerations
Operating Room
Eye shields for OR personnel
Wave length specific glass inserts on windows and doors
Signs identifying laser use
Drapes and towels – cloth with high porosity / wet
Fire extinguisher, water bucket

18. Recommendations American National Standards for the Safe use of Lasers in Health Care Facilities
I All persons should be aware of areas of laser use, and controlled access to these areas must be maintained
Nominal hazard zone is identified to prevent unintentional exposure to the laser beam
Regulation laser signs should be placed at all entrances to laser treatment areas
Doors in the nominal hazard zone should remain closed and windows--including door windows--should be covered as appropriate to the laser used
The nominal hazard zone should be occupied only by authorized persons (including patients) or health care personnel approved by the laser safety officer.

19. II Everyone in the nominal hazard zone should wear appropriate eyewear
All personnel in the nominal hazard zone should wear protective eyewear, labeled with the appropriate optical density and wavelength for the laser in use
The patient's eyes and eyelids should be protected from the laser (eg, wet eyepads, laser protective eyewear, laser specific eye shield)

20. III All persons in the laser treatment area
should be protected from laser beam
exposures to their skin and other
nontargeted tissues
Exposed tissues around the operative site should be protected with saline-saturated or water-saturated fire/flame-retardant materials (eg, towels, sponges) when thermally intensive lasers are being used. These materials should be remoistened periodically to ensure proper protection
Anodized, dull, nonreflective, or matte-finished instruments should be used near the laser site
When a fiber is used to deliver laser energy through an endoscope, the end of the fiber must extend at least I cm past the end of the endoscope

21. IV Exposure to smoke plume generated during laser
surgery should be reduced by implementing a
variety of engineering controls
Smoke plume inhalation should be reduced by implementing various controls that include but are not limited to the use of
* high-filtration surgical masks,
* wall suction units with in-line filters, and
* smoke evacuator units.

22. Laser Plumes Carbonised tissue,blood and virus(0.1-0.8µm)
Occupational Hazard (National Institute for Occupational Safety and Health)
Hydrocarbons, including acetone, isopropanol, toluene, formaldehyde, and cyanide
Smoke plume
- respiratory irritation
- viral infection
- mutagenic and carcinogenic potential.

23. V All persons in the laser treatment area should be protected from flammability hazards associated with laser usage.
Personnel using lasers should be aware of the fire hazards associated with laser use. Items with the potential for causing fire, bums, or explosions include
* flammable liquids or combustible ointments (eg, skin prep solutions, oil-based lubricants),
* gases (eg, oxygen, methane, anesthetic agents),
* plastics,
* electrical failures,
* paper or gauze materials,
* surgical drapes,
* adhesive or plastic tapes, and endotracheal tubes

24. Fire extinguishers and water/saline should be immediately available where lasers are used.
Special fire/flame-retardant drapes or moistened, reusable fabrics should be used to drape around areas that are close to the laser treatment site
An endotracheal tube used during laser procedures in the patient's airway or aerodigestive tract should have protection or be specially designed to minimize the potential for fire.

25. VI All persons in the laser treatment area should be protected from electrical hazards associated with laser use
Visual inspection of laser equipment should be performed by the laser operator after setup
Laser service and preventive maintenance should be documented

26. VII Personnel working in the nominal hazard zone
should demonstrate competency commensurate
with their responsibilities
Laser safety programs should include but not be limited
* to delegation of authority and responsibility for the supervision of laser safety to a laser safety officer or his/her designee;
* criteria and authorized procedures for all health care personnel working in nominal hazard zones;
* identification of laser hazards and appropriate control measures;
* management and reporting of accidents or incidents related to laser procedures, including action plans to prevent reoccurrences; and
* fundamentals of laser physics, tissue interaction, instrumentation, and delivery systems

27. VIII Policies and procedures for laser safety
should be developed with regard to
individual practice settings, applicable
standards, and federal and state
regulations. They should be reviewed
periodically, revised as necessary, and
readily available to all personnel.

28. Laser airway surgery Endotracheal intubation Advantages Disadvantages
secured airway
ability to monitor ETCO2 and O2 conc.
decreased risk of soiling the distal airway with debris,
blood, or gastric contents.
Disadvantages
risk of an ETT fire,
high AWP
high resistance with spontaneous ventilation
difficulty in suction

29. Special ETTs for use in laser surgery
Red rubber and PVC tubes are at risk of burning
PVC tubes seconds / red rubber tubes seconds
Low cost alternative
– aluminium foil wrap
- cover cuff with moist gauze
- methylene blue in saline for cuff inflation

30. Special ETT’s Norton - coiled metal rings without cuff
Bivona Fome-Cuff - aluminum tube coated with silicone with polyurethane foam cuff
Xomed Laser-Shield - silicone and non-reflecting metal particles
Malinckrodt Laser-Flex - coiled and flexible metal rings with two distal plastic cuffs
Sheridan Laser-Trach - red latex covered with atraumatic screen with latex distal cuff
Rusch Lasertubus – porous sponge coating and doublee cuff (one inside other)

31. Laser airway surgery Without Endotracheal intubation
Ventilating bronchoscope
Jet ventilation
- Sander’s injector
Advantages
Surgical convenience
No risk of ETT fire

32. Laser airway surgery Disadvantages Unable to monitor pCO2
Contamination of lower resp. tract
Intermittent endotracheal intubation

33. Airway Fire Combustion Flammable substrate Oxidant Speed of combustion
Incidence – 1.5%

34. Airway Fire Prevention Non flammable substrate / jet ventilation
Reducing O2 (30%)
Avoid N2O
Helium (high thermal conductivity)
Avoid Flash point(below critical temp.)

35. Airway Fire Management of an airway fire:
Plan ahead, review plan with team.
Immediately stop ventilation.
Disconnect circuit (blow torch effect with flaming ETT and 02 flow).
Remove and extinguished flaming ETT in a bucket of water.
Extinguish any flaming debris in pharynx with water or saline.

36. Reintubate, ventilate with 100% O2,  flush pharynx with cold water.
Flexible and rigid  bronchoscopy to assess damage and remove debris.
consider steroids,  humidified gases, and prolonged ventilation in ICU.
Consider tracheostomy if severe lower airway burn.
Monitor CXR, ECG, and ABG's.

37. Anesthetic considerations
surgical procedure
Patient’s pre-existing conditions
Hazards of laser surgery to the patient, OR personnel and equipment

38. Anesthesiologist must be aware of
Laser medium
Physical properties
Vital structures around the point of focus
Iceberg effect

39. Anesthetic plan
Preoperative evaluation of the airway (stridor, voice quality, ventilation pattern, flow volume loops, CT, MRI, or fiberoptic airway evaluation)
Mutual planning with the surgeon.
Aspiration prophylaxis
Total iv anesthesia (propofol, remifentanil, short acting relaxant)
Xylocaine spray

40. Tooth guard.
Methylene blue in ETT cuff.
Saline gauze protection of face and airway and keep mucosal surfaces moist
Laser should be used in short repeated bursts (pulse), rather than in a prolonged continuous mode.
Communicate and monitor video camera for signs of airway fire.
O2 < 30% using an air-oxygen mixture, avoid N2O and volatile anesthetic agents.

41. Transcutaneous CO2 monitoring if available may be helpful.
Esmolol and NTG immediately available for patients with CAD risk factors.
smooth emergence with minimal bleeding, coughing or laryngeal spasm