Download - Anesthesia for laser surgery ranjith
Anesthesia for LASER surgery
Presenter: Dr.Ranjith Nelluri
( MD 2nd year)
Moderator: Dr.Varaprasad
(Prof&HOD)
LASER
• Light Amplification of the Stimulated Emission of Radiation
• Intense controlled beam of light
• Characteristics :
- Monochromatic (same wavelength )
- coherence (one phase)
- collimation ( parallel direction)
LASER LIGHT
1. Monochromatic
2. Consists of photons-well defined very narrow band of wave lenghts.
3. Coherent (electromagnetic fields of all photons oscillate synchronously in identical phase).
4. Beams are collimated (minimal dispersion-parallel).
ORDINARY LIGHT
• Polychromatic
• Wide spectrum of wave lengths.
• Electromagnetic fields phased randomly.
• Spread out in all directions from a point of source.
HISTORY
• 1864 – Maxwell-electrical,magnetic Oscillations-299,792,458 M/Sec
• Max Planck-photo Electric Effect-
1st Step Towards Laser Physics
1905 – Einstein –
- Theoretical Basis For Laser Action
- Electromagnetic Radiation Consists Of Photons
Equipment• Laser medium:
contains the atoms whose electrons create the laser light
• Resonating mirrors:
to boost laser efficacy
• Energy source:
to excite or pump the atoms of the laser medium into producing laser light
Laser medium
• Gaseous medium:
CO2, Argon, Krypton, or Helium-Neon
• Solid medium:
- solid rods of laser passive material containing small quantities of ionic impurities(Dopants)
- Commonly used dopants:
Chromium ( ruby laser)
neodymium (Nd), Holmium(Ho)
- Synthetic gem cystals like Yttrium-aluminium-garnet(YAG) or glass are used
Advantage and clinical uses of
laser
– Scalpel and electro coagulator.
– Allow precise microsurgery.
– Relatively dry field.
– Less postoperative edema and
pain with lower infection rate.
BIOLOGIC EFFECTS OF LASER LIGHT
• Reflection
• Transmission
• Scatter
• Absorption
BIOLOGIC EFFECTS OF LASER LIGHT
Biological effects of laser
CRITICAL TEMP (0C) BIOLOGICAL EVENT
42 Warmed
45Cell death, edema,
endothelial damage
60 Protein coagulation
80 Collagen denaturation
100 Tissue boils
210 Dehydrated tissue burns
CO2 LASER
• Wavelength 10,600 nm
• Absorbed by water
• Cells are heated to the point of vaporisation
• Penetrate only shallow depth
• Used in aesthetic facial surgery,vocal cord and
airway lesions
Nd-YAG LASER
• Near infrared 1064nm
• Penetrate depth of 1cm
• Absorbed by dark matter
• Produces less vaporisation and more thermal coagulation
• Can cause delayed tissue necrosis
• Used in airway neoplasms, vascular malformations,opthalmic surgery
Pulsed dye laser
• Targets RBC within blood vessels
• Minimal epidermal scarring
• Used in dermatology eg: portwine stain,
tattoo erasion
Laser hazards
Four major categories
• Atmospheric contamination
• Perforation of a vessel or structure
• Embolism
• Inappropriate energy transfer
Atmospheric contamination(Laser Plume)
• Vaporization of tissue by laser radiation, produces a plume of smoke and fine particulates (mean size 0.31 µm; range 0.1 to 0.8 µm) sized within the range of particles that are efficiently transported and deposited in the alveoli
• headaches, tearing, and nausea as a consequence of inhalation
• Deposition of laser plume can cause interstitial pneumonia, bronchiolitis, reduced mucociliary clearance, inflammation, and emphysema.
Atmospheric contamination(Laser Plume)
• CO2 lasers seem to produce the most smoke because of vaporization
of tissue,
• Nd:YAG contact probes produce much less.
• use an efficient smoke evacuator at the surgical site.
• Ordinary surgical masks efficiently filter particles only down to 3 µm,
• and special high-efficiency masks (e.g., The Protector II; Anago, Fort
Worth, TX) are required to catch laser plume particulates.
• The high-efficiency masks are less effective when wet and may need
to be changed periodically
Tissue and Vessel perforation
• Misdirected laser energy may perforate a viscus or a large blood
vessel
• vessels >5 mm are not coagulable by laser
• Laser-induced pneumothorax has been reported after a laryngeal
procedure.
• With an Nd:YAG system, the depth of damage is impossible to assess
accurately or immediately,
• perforation and bleeding may not occur until edema and necrosis
have become maximal several days postoperatively.
Embolism
• The Nd:YAG laser system has been associated with venous
gas embolism
• The laser and its contact probe were not directly
responsible for the injury, but a liquid (saline) coolant is
• Continuous airway CO2 monitoring is highly recommended
for detection of embolization or hypercapnia
Energy transfer to an inappropriate location
• All available medical laser wavelengths are transmitted
transparently through air and are well reflected by smooth
metal surfaces.
• Pressing the laser control trigger at the wrong time can
deliver damaging laser light across the wound to sites at
which surgical ablation was not desired
• Can damage colleagues’ eyes, ignition of surgical drapes
and, ET tube fire during airway surgery.
Eye protection
• the eyes of the operating room staff and the patient be protected during laser surgery
• Errant infrared energy from a CO2 laser can quickly cause a serious corneal injury
• argon, KTP:Nd:YAG, or ruby lasers may burn the retina
Eye protection
• The lids of patients’ nonoperated eyes should be taped
closed and then covered with an opaque, saline-soaked knit
or metal shield
• Operating room personnel must wear safety goggles or
lenses specific for the specific laser wavelength in use.
• Using the wrong filter provides no protection.
• Safety goggles should provide wraparound protection
from reflected light.
ET tube fires
• Incidence o.5% - 1.5%
• Fires can result from direct laser illumination, reflected
laser light, or incandescent particles of tissue blown from
the surgical site
• Initially, most fires are located solely on the external
surface of the endotracheal tube, where they can cause
local thermal destruction.
• Blowtorch-like flame
• If a fire is unrecognized and burns through to the interior of the tube, the oxygen-enriched gas combined with the to-and-fro gas flow owing to ventilation
• blowing heat and toxic products of combustion down to the pulmonary parenchyma
Airway Fire Protocol
• Remove Source
• Disconnect Circuit
• Extubate
• Mask with 100% O2
• Start TIVA
• DL/Bronch for damage evaluation and removal of debris
• Reintubate if significant damage
• Fiberoptic bronchoscopy and lavage may be necessary for blowtorch fire
• Severe damage may require tracheostomy
• Assess oropharynx
Reduction of the flammability of ETT
A. The use of special type of laser resistant tracheal tube.
B. Wrapped standard tubes.
Reduction of the flammability of ETT
A. The use of special type of laser resistant tracheal tube;
• These tubes resist laser beams ,more bulky, stiffer
• Disadvantage: Traumatic (mucosal abrasion) Reflect laser beam and transfer heat No Cuff protectionExpensive
Laser resistant tracheal tube
a. The Norton tube:
• Reusable
• Stainless steel
• Flexible tube
• No cuff
b.The Laser Flex tube (Mallinckrodt laser tube):
• Airtight stainless steel tube
• Flexible
• Uncuffed or with two cuffs
Laser resistant tracheal tube
c.The Laser-Shield II (Xomed-laser shield II tube):
• Silicone tube
• Inner aluminum wrap
• Outer Teflon coating
d. The Bivona Fome-Cuff laser tube:
• Designed to solve the perforated-cuff-deflation-problem.
• It consists of an aluminum wrapped silicone tube with unique self inflating foam sponge filled cuff which prevent deflation after
puncture.
METAL TUBES
• Inflammable• Thick wall, bulky• Difficult to place
B. Wrapped standard tubes:
• Standard tracheal tubes (rubber, silicon, and PVC).
• Wrapped with laser resistant material (except the cuff).
• the wrapped material may be:
Aluminum or copper foil tape with adhesive back.
Merocel laser guard (merocel wrap).
• Disadvantage of wrapping:
– No cuff protection.
– Add thickness to the tube.
– Not an FDA approved device.
– May reflect laser beam to non target tissue.
–Protection varies with the type of the metal foil used.
–Air way obstruction.
– Rough edges may cause damage to mucosal surface.
Wrapped standard tubes
Wrapped standard tubes
• Mechanism of wrapping:
– Paint the tube with medical adhesive such as benzoin.
– Cut the end of the tape with scalpel to approximately 60 degree.
– Start wrapping from the junction of the tube and the proximal end of the cuff
– Wrapping in spiral with 30% to 50% overlap layer.
– Wrapping include the inflation tube of the cuff.
Wrapped standard tubes
Protection of the cuff:
Filling the cuff with saline colored with methylene blue.
Place the cuff distally in the trachea and covered visible cuff with moistened cotton pledgets.
Anesthetic Goals for Laser Airway
- Provide:• Safe environment for patient and staff
• Quiet surgical field
• Analgesia and anesthesia
- Minimize Complications
Anesthetic Techniques for Laser AirwaySurgery
1) Non-intubation techniques
• Apneic Oxygenation
• Spontaneous Ventilation
• Jet Ventilation
2) Intubation Techniques
Apneic Oxygenation
Advantages
• Periods of apnea can alternate with periods of laser resection
• Excellent visibility of surgical field
• Potential trauma to airway is avoided
Disadvantages
• Surgical time limit
• Inadequate ventilation
• Aspiration risk
Spontaneous Ventilation
Advantages
• Evaluate vocal cord
function
• Excellent visualization of
surgical field
• Good for otherwise
unstable patients with
compromised airway
Disadvantages
• Oxygenation/ventilation
more difficult to assess
• Surgical field not still
• Risk of aspiration
• Depth of anesthesia not
consistent
Jet VentilationAdvantages
• Decreased risk of airway fire
• Improved surgical field visibility
• Atraumatic airway manipulation
Disadvantages
• Difficult to control ventilation, likely
hypoventilation
• Oxygenation/ventilation cannot be
assessed
• Muscle relaxation required
• Increased aspiration risk
• Inability to use anesthetic gases
• Misdirection of jet may
• cause gastric distension or
• barotrauma
Intubation
Advantages
• Secure airway, less risk of
aspiration
• Controlled ventilation
• Administer anesthetic
gases
• Monitor O2 and EtCO2
concentrations
Disadvantages
• ETT may obstruct surgical
view
• Airway trauma
• ? Difficult Airway
• No ETT exists which
decreases risk of airway
fire to zero
CONCLUSION
• SPECIAL ETT
• N20,FIO2,inhalational anaesthetics support
combustion
• Special anaesthetic techniques
• Careful monitoring.
• Effective prevention,management of complications
SUMMARY
• Awareness of Hazards
• Availability of equipment
• Airway
• Anesthetic plan
• Arguments
THANK YOU