Lasers and anaesthesia .bapu

LASERS AND LASERS AND ANAESTHESIAANAESTHESIA

Dr.P.Narasimha Reddy,Dr.P.Narasimha Reddy,

Professor,Professor,

Dept of Anaesthesiology,Dept of Anaesthesiology,

Narayana medical college,Narayana medical college,

Nellore.Nellore.

Laser printer

Laser pointer

Laser: everywhere in your life

““Never are cooperation and Never are cooperation and communication between surgeon communication between surgeon and anaesthetist more impartant and anaesthetist more impartant than during head and neck surgery.”than during head and neck surgery.”

- - MORGAN Clinical anaesthesiaMORGAN Clinical anaesthesia

IntroductionIntroduction1. history1. history

2.properties of laser2.properties of laser

3.basic physics3.basic physics

4.proreties of laser4.proreties of laser

5.laser hardware5.laser hardware

6.biological effects6.biological effects

7.applications of laser7.applications of laser8.dangers of lasers8.dangers of lasers

9.anaesthesia considerations9.anaesthesia considerations

10.protection strategies10.protection strategies

LL -- LIGHTLIGHT AA -- AMPLIFICATION BYAMPLIFICATION BY SS -- STIMULATEDSTIMULATED EE -- EMISSION OFEMISSION OF RR -- RADIATIONRADIATION

TRANSFER OF LARGE QUANTITIES OF TRANSFER OF LARGE QUANTITIES OF ENERGY RAPIDLY TO REMOTE LOCATIONSENERGY RAPIDLY TO REMOTE LOCATIONS

VISUAL LIGHT IS ELECTROMAGNETIC VISUAL LIGHT IS ELECTROMAGNETIC RADIATION (RADIOWAVES,X- RAYS,GAMMA RADIATION (RADIOWAVES,X- RAYS,GAMMA RAYS)RAYS)

1864 – MAXWELL-ELECTRICAL,MAGNETIC 1864 – MAXWELL-ELECTRICAL,MAGNETIC OSCILLATIONS- 299,792,458 m/secOSCILLATIONS- 299,792,458 m/sec

- MAX PLANCK-PHOTO ELECTRIC - MAX PLANCK-PHOTO ELECTRIC EFFECT-1 st STEP TOWARDS EFFECT-1 st STEP TOWARDS

LASER PHYSICSLASER PHYSICS

1905 – EINSTEIN – THEORETICAL BASIS 1905 – EINSTEIN – THEORETICAL BASIS FOR LASER ACTION FOR LASER ACTION

- ELECTROMAGNETIC RADIATION - ELECTROMAGNETIC RADIATION CONSISTS OF PHOTONSCONSISTS OF PHOTONS

PROPERTIES OF PHOTONSPROPERTIES OF PHOTONS

1.1. Properties consistent with both particles and waves.Properties consistent with both particles and waves.2.2. Propagate in vaccum with spreads of 299,792,458 Propagate in vaccum with spreads of 299,792,458

m/sec.m/sec.3.3. Energy proportional to their vibrational frequencyEnergy proportional to their vibrational frequency E(joules) =n h vE(joules) =n h v n -an integral numbern -an integral number

h – Planck constant 6.63 h – Planck constant 6.63 × 10¯× 10¯ 2424 j/sec j/secv – photon frequency in hertzv – photon frequency in hertz

4.4. Their wave lenghts can be calculated as followsTheir wave lenghts can be calculated as follows ΛΛ(m)=(m)=2.998×10 to the power of 8 m/sec2.998×10 to the power of 8 m/sec V (hz)V (hz) wave lenghts of visible light is 385 to 760 nmwave lenghts of visible light is 385 to 760 nm

1.1. MonochromaticMonochromatic2.2. Consists of photons-well Consists of photons-well

defined very narrow band defined very narrow band of wave lenghts.of wave lenghts.

3.3. Coherent (electromagnetic Coherent (electromagnetic fields of all photons fields of all photons oscillate synchronously in oscillate synchronously in identical phase).identical phase).

4.4. Beams are collimated Beams are collimated (minimal dispersion-(minimal dispersion-parallel).parallel).

Allow lasers to generate Allow lasers to generate intense light beams to send intense light beams to send such beams efficiently & such beams efficiently & accurately through lenses-accurately through lenses-deliver intense energy to deliver intense energy to small target sitessmall target sites

PolychromaticPolychromatic Wide spectrum of wave Wide spectrum of wave

lengths.lengths.

Electromagnetic fields Electromagnetic fields phased randomly.phased randomly.

Spread out in all directions Spread out in all directions from a point of source.from a point of source.

Basic concepts for a laserBasic concepts for a laser

Absorption Absorption

Spontaneous Emission Spontaneous Emission

Stimulated Emission Stimulated Emission

Population inversionPopulation inversion

AbsorptionAbsorption

Energy is absorbed by an atom, the electrons Energy is absorbed by an atom, the electrons are are excitedexcited into vacant energy shells. into vacant energy shells.

Spontaneous EmissionSpontaneous Emission

The atom decays from level 2 to level 1 The atom decays from level 2 to level 1 through the emission of a photon with the through the emission of a photon with the energy energy hvhv. It is a completely . It is a completely randomrandom process.process.

Stimulated Emission Stimulated Emission

atoms in an upper energy level can be atoms in an upper energy level can be triggered or stimulated in phase by an triggered or stimulated in phase by an incoming photonincoming photon of a of a specific energyspecific energy..

Stimulated EmissionStimulated Emission

The The stimulated photons stimulated photons have unique have unique properties: properties: • In phaseIn phase with the incident photon with the incident photon

• Same wavelengthSame wavelength as the incident as the incident photon photon

• Travel in Travel in same directionsame direction as incident as incident photon photon

Population InversionPopulation Inversion

A state in which a substance has been A state in which a substance has been energized, or excited to specific energy energized, or excited to specific energy levels.levels.

More atoms or molecules are in a higher More atoms or molecules are in a higher excited state. excited state.

The process of producing a population The process of producing a population inversion is called inversion is called pumpingpumping..

Examples: Examples:

→ →by lamps of appropriate intensityby lamps of appropriate intensity

→ →by electrical dischargeby electrical discharge

How a laser works?How a laser works?

1. High-voltage electricity causes the quartz flash tube to emit an intense burst of light, exciting some of Cr3+ in the ruby crystal to higher energy levels.

2. At a specific energy level, some Cr3+ emit photons. At first the photons are emitted in all directions. Photons from one Cr3+ stimulate emission of photons from other Cr3+ and the light intensity is rapidly amplified.

3. Mirrors at each end reflect the photons back and forth, continuing this process of stimulated emission and amplification.

4. The photons leave through the partially silvered mirror at one end. This is laser light.

Laser ConstructionLaser Construction

A A pump sourcepump source

A A gain mediumgain medium or laser medium. or laser medium.

Mirrors forming an Mirrors forming an optical resonator.optical resonator.

Pump SourcePump Source Provides energyProvides energy to the laser system to the laser system Examples: electrical discharges, Examples: electrical discharges,

flashlamps, arc lamps and chemical flashlamps, arc lamps and chemical reactions. reactions.

The type of pump source used depends The type of pump source used depends on the gain medium. on the gain medium.

→ →A helium-neon (HeNe) laser uses an A helium-neon (HeNe) laser uses an electrical discharge in the helium-electrical discharge in the helium-

neon gas mixture.neon gas mixture.

→ →Excimer lasers use a chemical reaction. Excimer lasers use a chemical reaction.

Optical ResonatorOptical Resonator Two parallel mirrors placed around the Two parallel mirrors placed around the

gain medium.gain medium. Light is reflected by the mirrors back Light is reflected by the mirrors back

into the medium and is amplified .into the medium and is amplified . The design and alignment of the The design and alignment of the

mirrors with respect to the medium is mirrors with respect to the medium is crucialcrucial..

Spinning mirrors, modulators, filters Spinning mirrors, modulators, filters and absorbers may be added to and absorbers may be added to produce a variety of effects on the produce a variety of effects on the laser output.laser output.

Laser medium containing the atoms whose Laser medium containing the atoms whose electrons create the laser lightelectrons create the laser light

Resonating mirrors - to boost laser Resonating mirrors - to boost laser efficiencyefficiency

Energy source- excite or pump the atoms Energy source- excite or pump the atoms of the laser medium into producing laser of the laser medium into producing laser light.light.

Gas lasers- co2 ,Argon, krypton, helium – Gas lasers- co2 ,Argon, krypton, helium – neonneon

Laser TypesLaser Types According to the According to the active materialactive material: :

solid-state, liquid, gas, excimer or solid-state, liquid, gas, excimer or semiconductor lasers.semiconductor lasers.

According to the According to the wavelengthwavelength: :

infra-red, visible, ultra-violet (UV) or infra-red, visible, ultra-violet (UV) or x-ray lasers.x-ray lasers.

Solid-state LaserSolid-state Laser Example: Ruby LaserExample: Ruby Laser Operation wavelength: 694.3 nm Operation wavelength: 694.3 nm

(IR)(IR) 3 level system: absorbs 3 level system: absorbs

green/bluegreen/blue•Gain Medium: crystal of aluminum oxide (Al2O3)

with small part of atoms of aluminum is replaced with Cr3+ ions.•Pump source: flash lamp •The ends of ruby rod serve as laser mirrors.

Gas LaserGas Laser Example: Helium-neon laser (He-Ne laser)Example: Helium-neon laser (He-Ne laser) Operation wavelength: 632.8 nm Operation wavelength: 632.8 nm Pump source: electrical dischargePump source: electrical discharge Gain medium : ratio 5:1 mixture of helium and Gain medium : ratio 5:1 mixture of helium and

neon gasesneon gases

Schematic diagram of a dye laser

DYE LASER

A dye laser can be considered to be basically a four-level system. The energy absorbed by the dye creates a population inversion, moving the electrons into an excited state.

SOLIDS-SOLIDS- DOPANTS-CHROMIUM(AS DOPANTS-CHROMIUM(AS IN RUBY LASER), IN RUBY LASER), NEODYMIUM(Nd),HOLMIUM (Ho), NEODYMIUM(Nd),HOLMIUM (Ho), YAG(YTTRIUM,ALUMINIUM,GARNET-YAG(YTTRIUM,ALUMINIUM,GARNET-SYNTHETIC GEM CRYSTAL)SYNTHETIC GEM CRYSTAL)

-PUMPED BY HIGH ENERGY PHOTONS -PUMPED BY HIGH ENERGY PHOTONS FROM XENON FLASH LAMP.FROM XENON FLASH LAMP.

LIQUIDSLIQUIDS – YET TO APPEAR – YET TO APPEAR

BIOLOGIC EFFECTS OF LASER BIOLOGIC EFFECTS OF LASER LIGHTLIGHT

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Biological effects of laserBiological effects of laser

CRITICAL TEMP CRITICAL TEMP ((00C)C)

BIOLOGICAL BIOLOGICAL EVENTEVENT

4242 WarmedWarmed

4545Cell death, edema,Cell death, edema,

endothelial damageendothelial damage

6060 Protein coagulationProtein coagulation

8080 Collagen Collagen denaturationdenaturation

100100 Tissue boilsTissue boils

210210 Dehydrated tissue Dehydrated tissue burnsburns

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Biological effects of laserBiological effects of laser Carbon dioxide LaserCarbon dioxide Laser

• Completely absorbed by water in Completely absorbed by water in first few layers of cells – first few layers of cells – vaporization of surface tissue with vaporization of surface tissue with little damage to underlying tissue.little damage to underlying tissue.

Nd-YAG LaserNd-YAG Laser• Less absorbed by water and beam Less absorbed by water and beam

diffuses through several millimeters diffuses through several millimeters – energy is disseminated producing – energy is disseminated producing less vaporization and more less vaporization and more coagulation (Cooking Effect).coagulation (Cooking Effect).

commonly used Laserlightscommonly used Laserlights

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

LASERS ARE NOT VERY EFFICIENT AT LASERS ARE NOT VERY EFFICIENT AT CONVERTING ELECTRICITY INTO CONVERTING ELECTRICITY INTO LIGHT,THEY REQUIRE A LARGE POWER LIGHT,THEY REQUIRE A LARGE POWER SUPPLY.SUPPLY.

FREQENCY DOUBLES TO CONVERT FREQENCY DOUBLES TO CONVERT LASER LIGHT TO DIFFERRENT WAVE LASER LIGHT TO DIFFERRENT WAVE LENGTH ENHANCING THERAUPETIC LENGTH ENHANCING THERAUPETIC FLEXIBILITYFLEXIBILITY

DR.GERRY ROSSDR.GERRY ROSS

CLINICAL APPLICATIONSCLINICAL APPLICATIONS

ScalpelsScalpels ElectrocoagulationElectrocoagulation Highly precise micro surgery (confined Highly precise micro surgery (confined

or difficult to reach sites-percutaneous or difficult to reach sites-percutaneous discectomy, endovascular angioplasty)discectomy, endovascular angioplasty)

Small target areas-concentrate intensity Small target areas-concentrate intensity or power per area enormously.or power per area enormously.

Precise rapid evoparisation of tissuesPrecise rapid evoparisation of tissues

ARGON LASER PAN RETINALARGON LASER PAN RETINAL

COSMETIC LASER COSMETIC LASER SURGERYSURGERY

LASER IRIDOTOMYLASER IRIDOTOMY

LASER REVASCULARISATIONLASER REVASCULARISATION

LASER TO RESHAPE CORNEALASER TO RESHAPE CORNEA

LASER SKIN RESURFACINGLASER SKIN RESURFACING

LASER LIPOSUCTIONLASER LIPOSUCTION

HAIR REMOVALHAIR REMOVAL

LASER PLASTIC SURGERY-LASER PLASTIC SURGERY-SAGGINGSAGGING

LASER TO MAKE AN INCISIONLASER TO MAKE AN INCISION

LASER VISION CORRECTIONLASER VISION CORRECTION

ADVANTAGESADVANTAGESLaser surgeryLaser surgery Relatively dryRelatively dry Near instantaneous ceiling of blood Near instantaneous ceiling of blood

vessels, lymphatics even in presence vessels, lymphatics even in presence of coagulation abnormalitiesof coagulation abnormalities

Faster healingFaster healing Lower infection ratesLower infection rates

LASER HAZARDSLASER HAZARDS

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Safety ConsiderationsSafety Considerations

LASER HAZARDSLASER HAZARDS

1.1. Atmospheric contamination-laser Atmospheric contamination-laser plumesplumes

-Objectional odour,tears, -Objectional odour,tears, headache, nausea.headache, nausea.

-Interstitial pneumonia, -Interstitial pneumonia, bronchiolitis,emphysemabronchiolitis,emphysema

-Mutogenic & teratogenic-Mutogenic & teratogenic

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Laser plumeLaser plume ProtectionProtection

•Efficient smoke evacuator at Efficient smoke evacuator at surgical site.surgical site.

•Use of special high efficiency Use of special high efficiency mask : mask : Tex, protector II, Ango, Tex, protector II, Ango, Fort worthFort worth

•Ordinary surgical mask gives Ordinary surgical mask gives protection from molecules up to protection from molecules up to 3.0 µm size.3.0 µm size.

Plume of smoke and fine particulates (mean size 0.31um)Plume of smoke and fine particulates (mean size 0.31um) Efficiently transported and deposited in the alveoliEfficiently transported and deposited in the alveoli Sensitive individuals: headaches, tearing, and nausea Sensitive individuals: headaches, tearing, and nausea

after inhalationafter inhalation Animal study: interstitial pneumonia, bronchiolitis, Animal study: interstitial pneumonia, bronchiolitis,

reduced mucociliary clearance, inflammation, emphysemareduced mucociliary clearance, inflammation, emphysema PreventionPrevention

→ → smoke evacuatorsmoke evacuator → → high-efficiency maskshigh-efficiency masks

Atmospheric contamination

LASER HAZARDS CONTDLASER HAZARDS CONTD……

2.Tissue and vessel perforation(misdirected 2.Tissue and vessel perforation(misdirected laser laser energy)energy)

-Viscous perforation-Viscous perforation-vessels more than 5 mm not coaguable by -vessels more than 5 mm not coaguable by

laserslasers-Pneumothorax(after -Pneumothorax(after

laryngeal perforation)laryngeal perforation) Perforational bleeding after several days post Perforational bleeding after several days post

operatively with edema and necrosis.operatively with edema and necrosis.3.Embolism- VAE3.Embolism- VAE4.Energy transfer to an inappropriate location4.Energy transfer to an inappropriate location

Incidentally pressing the laser control triggerIncidentally pressing the laser control trigger Tissue damage outside of surgical siteTissue damage outside of surgical site Drape fireDrape fire Eye (patient or other medical staff)Eye (patient or other medical staff) Endotracheal tube firesEndotracheal tube fires

Inappropriate energy transfer

EYE PROTECTIONEYE PROTECTION Operating room staff- goggles or Operating room staff- goggles or

lenses specific for specific laser wave lenses specific for specific laser wave length.length.

Patient-non operated eye-taped, Patient-non operated eye-taped, closed,covered with an opaque saline closed,covered with an opaque saline soaked knit or metal shields.soaked knit or metal shields.

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Eyes ProtectionEyes Protection Protection of OT staff eyes :Protection of OT staff eyes :

• Safety goggles or lenses specific Safety goggles or lenses specific for laser wave length in use.for laser wave length in use.

• COCO22 Laser – any clear glass or Laser – any clear glass or plastic lenses.plastic lenses.

• Nd:YAG Laser – green tinted or Nd:YAG Laser – green tinted or clear lenses.clear lenses.

• Argon & Krypton – Amber orange.Argon & Krypton – Amber orange.• KTP-Nd:YAG – Red.KTP-Nd:YAG – Red.

E.T.T. FIRESE.T.T. FIRES Airway surgery-Airway surgery-

ignition of ETT, ignition of ETT, cuff, or cottonoidscuff, or cottonoids

Most fires on Most fires on external surface of external surface of ETT-because of ETT-because of OO22. .

Approaches to reduce the incidence of airway fire

Reduce the flammability of the Reduce the flammability of the endotracheal tubeendotracheal tube

Use Venturi ventilationUse Venturi ventilation Use intermittent apnea techniqueUse intermittent apnea technique

Incidence: 0.5 – 1.5 %Incidence: 0.5 – 1.5 % Source: Source:

• direct laser illuminationdirect laser illumination• reflected laser lightreflected laser light• incandescent particles of tissue blown incandescent particles of tissue blown

from the surgical sitefrom the surgical site

Endotracheal tube fires

E.T.T. FIRES (CONTD….)E.T.T. FIRES (CONTD….)Reduction of flammability of ETTReduction of flammability of ETT Choice of ETT.Choice of ETT. Extrinsic protection:Extrinsic protection:

- Moistened muslin (dry-fire)- Moistened muslin (dry-fire)- Dental acrilic (trauma)- Dental acrilic (trauma)

3. ETT taping-aluminium , copper foil with 3. ETT taping-aluminium , copper foil with adhesive backing.Cuff is not protected- well adhesive backing.Cuff is not protected- well supported by medical literature-no fda supported by medical literature-no fda approval.Lead foil should not be used-toxic approval.Lead foil should not be used-toxic to airwayto airway

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 Combustion-resistant, kink-resistant

Thick-walled flammable cuff, transfers heat, reflects laser, cumbersome

A clean tube wiped A clean tube wiped with alcohol later with alcohol later with mastisol or with mastisol or tincture benzion.tincture benzion.

The end of the tape cut The end of the tape cut at 60°- cut edge at 60°- cut edge proximal end of cuff proximal end of cuff junction- rapped in junction- rapped in spiral way with 30% spiral way with 30% overlap,to the exit overlap,to the exit point of cuff pilot point of cuff pilot tube tube

No cuff protectionNo cuff protection Adds thickness to tubeAdds thickness to tube Not an FDA-approved deviceNot an FDA-approved device Protection varies with type of metal foilProtection varies with type of metal foil Adhesive backing may igniteAdhesive backing may ignite May reflect laser on to non-targeted tissueMay reflect laser on to non-targeted tissue Rough edges may damage mucosal surfacessRough edges may damage mucosal surfacess

Disadvantages of wrapping

Oxygen and nitrous oxide are powerful Oxygen and nitrous oxide are powerful oxidizersoxidizers

Reduce FiOReduce FiO22 to minimum concentration to minimum concentration Helium may benefit as a diluent gasHelium may benefit as a diluent gas Volatile anesthetics currently used are Volatile anesthetics currently used are

nonflammable and nonexplosivenonflammable and nonexplosive Pyrolized toxic compoundsPyrolized toxic compounds

Effect of high oxygen and nitrous oxide gas mixture

FDA APPROVED ETT WRAPSFDA APPROVED ETT WRAPS

Merocel laser guard -Merocel laser guard -- Metal foil laminated to a - Metal foil laminated to a synthetic sponge kept moist synthetic sponge kept moist - protection against co2, argon, - protection against co2, argon, ktp:nd:yag (but not yag) lasersktp:nd:yag (but not yag) lasers- ETT diameter increased by 2 mm.- ETT diameter increased by 2 mm.- No protection for the cuff.- No protection for the cuff.

FDA APPROVED ETT WRAPS FDA APPROVED ETT WRAPS CONTDCONTD……

Integrated laser resistent coating in the Integrated laser resistent coating in the manufacture of ett- COmanufacture of ett- CO22 laser laser

- - XomedXomed laser shield tube laser shield tube (fabricated from silicon with an (fabricated from silicon with an outer layer of aluminium powder outer layer of aluminium powder with silicon-aluminised layer with silicon-aluminised layer extends over inflatable cuff.)extends over inflatable cuff.)

FDA APPROVED ETT WRAPS FDA APPROVED ETT WRAPS CONTD…CONTD…

.Laser shield ii- CO.Laser shield ii- CO22 ,ktp laser ,ktp laser

-silicon based wrapped by a coated -silicon based wrapped by a coated alluminium tapealluminium tape

- The cuff-unshielded silicon - The cuff-unshielded silicon elastoma-designed to be expanded elastoma-designed to be expanded with saline and methylene blue.with saline and methylene blue.

PROTECTION OF ETT CUFFPROTECTION OF ETT CUFF

1.1. standard hi-lo cuff -colored saline.standard hi-lo cuff -colored saline.

2.2. Cuff-placed as far distal in the trachea Cuff-placed as far distal in the trachea as possible.as possible.

3.3. Surgeon should cover the visible cuff Surgeon should cover the visible cuff with moistened cotton pledges-cotton with moistened cotton pledges-cotton strings attached to pledges replaced by strings attached to pledges replaced by wire- pledges re moistened as needed.wire- pledges re moistened as needed.

METAL ETTMETAL ETT1.1. NORTON DE VOS(1978NORTON DE VOS(1978))

- Interlocking stainless spiral coil - Interlocking stainless spiral coil (resembling electrical cable armour)-no (resembling electrical cable armour)-no cuff.cuff.

- Difficult ventillation-non compliance- Difficult ventillation-non compliance

22. LASER FLEX TUBE. LASER FLEX TUBE::

--Air tight stainless spiralAir tight stainless spiral

-Two distal saline inflatable -Two distal saline inflatable pvc pvc cuffscuffs

-resistent to CO-resistent to CO22 :ktp but not nd:yag :ktp but not nd:yag

6mm size6mm size

3.3. THE BIVONA FOAM CUFF:THE BIVONA FOAM CUFF:

--Aluminium spiral tubeAluminium spiral tube

-Outer covering of silicon-Outer covering of silicon

-Unique self inflating foam -Unique self inflating foam sponge filled cuff which prevents sponge filled cuff which prevents deflation after puncture.deflation after puncture.

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Precautions to prevent firePrecautions to prevent fire• Low FiOLow FiO2.2.

• Avoid nitrous oxide.Avoid nitrous oxide.• Cuff should be filled with saline Cuff should be filled with saline

with methylene blue.with methylene blue.• Addition of 2% lignocaine jelly in Addition of 2% lignocaine jelly in

water for filling of cuff.water for filling of cuff.• Limit laser density and duration.Limit laser density and duration.• Laser resistant tubes.Laser resistant tubes.• Saline soaked swabs in airway.Saline soaked swabs in airway.• Availability of source of water. Availability of source of water.

1.1. Regional anesthesia-best topical to nerve Regional anesthesia-best topical to nerve blocks with proper sedation especially for blocks with proper sedation especially for airway surgeryairway surgery..

LOCAL TOPICAL CREAM TOPICALLOCAL TOPICAL CREAM TOPICAL

2. 2. GENERAL ANESTHESIA-LARGE BORE GENERAL ANESTHESIA-LARGE BORE IV NEEDLEIV NEEDLE

- MAC- MAC

- TIVA- TIVA

- G.A.- G.A.

G.A.G.A. PremedicationPremedication:-sedation,analgesia,:-sedation,analgesia,

Parasympatholytics must(vagal hyperactivity-for Parasympatholytics must(vagal hyperactivity-for airway surgery).airway surgery).

Induction:-Induction:- i.V.,Inhalational better avoided. i.V.,Inhalational better avoided. ETTETT:relaxant:relaxant MaintainanceMaintainance:no N:no N22O, inhalational anaesthetic, FIOO, inhalational anaesthetic, FIO22

should be less than 40%.should be less than 40%. Spontaneous ventilationSpontaneous ventilation:(TIVA):(TIVA) Controlled ventilationControlled ventilation Jet ventilation(Jet ventilation(close or remote)close or remote)

-Endolaryngeal surgery-Endolaryngeal surgery-Complications:barotrauma,pneumothorax,co -Complications:barotrauma,pneumothorax,co poisoning,hypoxia.poisoning,hypoxia.

• BarotraumaBarotrauma• PneumothoraxPneumothorax• Restriction to only intravenous agentsRestriction to only intravenous agents• Gastric distentionGastric distention• Relative requirement for compliant lungsRelative requirement for compliant lungs

Jet ventilation

Intermittent apnea technique

• Hypoventilation• Pulmonary aspiration

MonitoringMonitoring

• Mandatory - pulse oximetryMandatory - pulse oximetry - ETCO2- ETCO2

- Temparature- Temparature

- TEE(VAE)- TEE(VAE)• Routine:-ECG/IBP/NIBP/CVP/ABGRoutine:-ECG/IBP/NIBP/CVP/ABG

AIRWAY FIRE CONTROL AIRWAY FIRE CONTROL PROTOCOLPROTOCOL

Surgeon & anaesthesiologist-act Surgeon & anaesthesiologist-act qiuckly,decisively& in a coordinated fashion.qiuckly,decisively& in a coordinated fashion.

Surgeon:qiuckly to remove the source.Surgeon:qiuckly to remove the source. Anaesthetist:stop ventilation,disconnect the Anaesthetist:stop ventilation,disconnect the

breathing circiut (temporarily)breathing circiut (temporarily)Flame extinguished with a bucket of Flame extinguished with a bucket of water(available)water(available)

Then ventilation with 100% OThen ventilation with 100% O22, anaesthesia , anaesthesia must be continued.must be continued.

• Remove source of fire (the laser!). Remove source of fire (the laser!). • Stop ventilating, disconnect circuit, extubate. Stop ventilating, disconnect circuit, extubate. • Extinguish fire in bucket of water (must have Extinguish fire in bucket of water (must have

one ready!). one ready!). • Mask ventilate with 100% OMask ventilate with 100% O22, continue , continue

anaesthesia i.v. anaesthesia i.v. • Direct laryngoscopy & rigid bronchoscopy for Direct laryngoscopy & rigid bronchoscopy for

damage and debris.damage and debris.

Airway fires protocol (I)

Reintubate if damage. Reintubate if damage. Blowtorch fire may need distal fibreoptic Blowtorch fire may need distal fibreoptic

bronchoscopy and lavage. bronchoscopy and lavage. Severe damage may need low Severe damage may need low

tracheostomy. tracheostomy. Assess oropharynx and face. Assess oropharynx and face. CXR. CXR. Steroids. Steroids.

Airway fires protocol (II)

AIRWAY FIRE CONTROL AIRWAY FIRE CONTROL PROTOCOLPROTOCOL

Direct laryngoscopy-survey damage, Direct laryngoscopy-survey damage, remove debris,gentle bronchial lavage.remove debris,gentle bronchial lavage.

Fibre optic assessment of most distal Fibre optic assessment of most distal airwaysairways

If pulmonary damage prolonged If pulmonary damage prolonged intubation & mechanical intubation & mechanical ventilation,brief course of high dose ventilation,brief course of high dose steroidssteroids

Applications of laserApplications of laser 1. 1. ScientificScientific a. Spectroscopya. Spectroscopy

b. Lunar laser ranging b. Lunar laser ranging

c. Photochemistry c. Photochemistry d. Laser cooling d. Laser cooling

e. Nuclear fusion e. Nuclear fusion

2 Military 2 Military a. Death raya. Death ray

b. Defensive b. Defensive applicationsapplications

c. Strategic defense c. Strategic defense initiativeinitiative

d. Laser sightd. Laser sight

e. Illuminatore. Illuminator

f. Rangefinderf. Rangefinder

g. Target designatorg. Target designator

Applications of laserApplications of laser

3. Medical3. Medical

a. eye surgerya. eye surgery

b. cosmetic b. cosmetic surgerysurgery

c. many morec. many more

Applications of laserApplications of laser

4. 4. Industry & CommercialIndustry & Commercial a. cutting, welding, markinga. cutting, welding, marking

b. CD player, DVD playerb. CD player, DVD player

c. Laser printers, laser pointersc. Laser printers, laser pointers

d. Photolithographyd. Photolithography

e. Laser light displaye. Laser light display

Applications of laserApplications of laser

CONCLUSIONSCONCLUSIONS Stimulation emission is the basis of laser Stimulation emission is the basis of laser

phenomenonphenomenon

COCO2 2 laser high risk of remote fires-laser high risk of remote fires-

invisible infrared –transmitted to surgical invisible infrared –transmitted to surgical site in a beam through free air site in a beam through free air

CONCLUSIONS (CONTD….)CONCLUSIONS (CONTD….)

Different laser sources – different eye Different laser sources – different eye protectionprotection- Co2 any glass / plastic- Co2 any glass / plastic

-Others-type specific protection-Others-type specific protection

CONCLUSIONSCONCLUSIONS (CONTD..) (CONTD..) SPECIAL ETTSPECIAL ETT

NN220,FIO0,FIO22,inhalational anaesthetics ,inhalational anaesthetics

support combustionsupport combustion Special anaesthetic techniquesSpecial anaesthetic techniques Careful monitoring.Careful monitoring. Effective prevention,management Effective prevention,management

of complicationsof complications

THANK YOUTHANK YOU

Any questions?Any questions?