Transcript Laser Surgery.ppt

‫بسم هللا الرحمن الرحیم‬
Anesthesia in
Laser Surgery
“Never are cooperation and
communication between surgeon
and anesthesiologist more important
than during head and neck surgery.”
Morgan, Clinical Anesthesiology
Physics of Laser light (I)
 Light Amplification by Stimulated
Emission of Radiation
 Electromagnetic radiation
 Einstein:
 all electromagnetic radiation consisted of
wavelike quanta called photons
→E (J) = h v
 Wavelength for visible light ranges
from 385nm to 760 nm
Physics of Laser light (II)
 Characteristics:
 Monochromatic (one wavelength)
 Coherent (oscillates in the same phase)
 Collimated (exists as a narrow, parallel beam)
 Intense light beams, intense energy
to small target sites
Laser system components
Laser system components
Light guide
Clinical applications
 Used as scalpels and
electrocoagulators
 Dermatology, thoracic surgery,
ophthalmology, gynaecology,
plastics, ENT, urology and
neurosurgery
Laser interaction with tissue
Used as scalpels and
electrocoagulators
Precise microsurgery
Relative “dry”
Less damage to
adjunct tissue
Less postoperative
pain and edema
Common used Laser lights
Laser media
Color
Wavelength
(nm)
Typical application
Carbon dioxide
Far infrared
10,600
General, cutting
Ruby
Red
694
Tattoos, nevi
KTP:YAG
Green
532
General,
pigmented lesions
Argon
Green
514
Vascular,
pigmented lesions
Xenon fluoride
Ultraviolet
351
Cornea, angioplasty
Laser Hazards
 Atmospheric contamination
 Perforation of a vessels or structure
 Embolism
 Inappropriate energy transfer
Atmospheric contamination
 Plume of smoke and fine particulates (mean size
0.31um)
 Efficiently transported and deposited in the
alveoli
 Sensitive individuals: headaches, tearing, and
nausea after inhalation
 Animal study: interstitial pneumonia, bronchiolitis,
reduced mucociliary clearance, inflammation,
emphysema
 Prevention
→ smoke evacuator
→ high-efficiency masks
Perforation
 Misdirected laser energy may perforate a
viscus or a large blood vessel
 Laser-induced pneumothorax
 Perforation may occur several days later
when edema and necrosis are maximal
Venous gas embolism
 Venous gas embolism when laparoscopic
or hysteroscopic laser surgery
 At hysteroscopy, liquid (saline) coolant is
the only safe option
 If coolant gas must be used, CO2 should
be considered
→ Continuous airway CO2 monitoring
Inappropriate energy transfer
 Incidentally pressing the laser control
trigger
 Tissue damage outside of surgical site
 Drape fire
 Eye (patient or other medical staff)
 Endotracheal tube fires
Endotracheal tube fires
 Incidence: 0.5 – 1.5 %
 Source:
– direct laser illumination
– reflected laser light
– incandescent particles of tissue blown from
the surgical site
Blowtorch ignition of an endotracheal tube.
Approaches to reduce the
incidence of airway fire
 Reduce the flammability of the
endotracheal tube
 Use Venturi ventilation
 Use intermittent apnea technique
Various endotracheal tubes for laser airway surgery
Type of tube
Advantages
Disadvantages
Polyvinyl
chloride
Inexpensive,
nonreflective
Low melting point, highly
combustible
Red rubber
Puncture-resistant,
maintains structure,
nonreflective
Highly combustible
Silicone
rubber
Nonreflective
Combustible, turns to
toxic ash
Metal
Combustionresistant, kinkresistant
Thick-walled flammable
cuff, transfers heat,
reflects laser,
cumbersome
Protection
of the endotracheal tubes
 wrapping with moistened muslin
 coating with dental acrylic
 wrapping with metallized foil tape
→ most popular approach
 aluminum foil
 copper foil
 plastic tape thinly coated with metal
Cuff wrapping technique
methylene blue
stained saline
instead of air
Disadvantages of wrapping
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No cuff protection
Adds thickness to tube
Not an FDA-approved device
Protection varies with type of metal foil
Adhesive backing may ignite
May reflect laser onto non-targeted tissue
Rough edges may damage mucosal surfacess
Effect of high oxygen and nitrous
oxide gas mixture
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Oxygen and nitrous oxide are powerful
oxidizers
Reduce FiO2 to minimum concentration
Helium may benefit as a diluent gas
Volatile anesthetics currently used are
nonflammable and nonexplosive
Pyrolized toxic compounds
Metal endotracheal tubes
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Norton. spiral wound stainless steel ETT
Bivona Fome-Cuff. aluminium spiral tube with
a silicone polyurethane foam cuff
Xomed Laser-Shield. silicone elastomer tube
containing metallic powder
Mallinckrodt Laser-Flex. airtight stainless
steel spiral wound tube with two PVC cuffs
Jet ventilation
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Barotrauma
Pneumothorax
Restriction to only intravenous agents
Gastric distention
Relative requirement for compliant lungs
Intermittent apnea technique
 Hypoventilation
 Pulmonary aspiration
Airway fires protocol (I)
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Remove source of fire (the laser!).
Stop ventilating, disconnect circuit, extubate.
Extinguish fire in bucket of water (MUST have
one ready!).
Mask ventilate with 100% O2, continue
anaesthesia i.v.
Direct laryngoscopy & rigid bronchoscopy for
damage and debris.
Airway fires protocol (II)
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Reintubate if damage.
Blowtorch fire may need distal fibreoptic
bronchoscopy and lavage.
Severe damage may need low
tracheostomy.
Assess oropharynx and face.
CXR.
Steroids.