ANAESTHETIC CONSIDERATIONS FOR LASER SURGERY

DR ANAMIKA YADAV

OBJECTIVES

• TYPES OF LASERS IN AIRWAY SURGERY• PREOPERATIVE ASSESSMENT ,

PREPARATION AND INDUCTION• AIRWAY MANAGEMENT AND

VENTILATION OPTIONS• LASER HAZARDS AND PREVENTION• CRISIS MANAGEMENT IN AIRWAY FIRES

LASERLIGHT AMPLIFICATION by STIMULATED

EMISSION of RADIATIONLasers provide the ability to transfer large quantitiesof energy rapidly and precisely to remotelocation,achieved with the use of coherentcollimated and monochromatic light focussed with the use of resonating mirrors or fibre optic bundles.Laser power density is the amount of power distributed within an area and is indicated in Watts per sq. cm.

ESSENTIAL COMPONENTS OF LASERLASER MEDIUM-GAS/SOLID WHOSE ELECTRONS CREATE LASER LIGHTRESONATING MIRRORS-TO BOOST LASER EFFICIENCYENERGY SOURCE-TO EXCITE ATOMS OF LASER MEDIUM INTO PRODUCING LASER LIGHT

PROPERTIES-

COHERENCE-ELECTROMAGNETIC FIELDS OF ALL PHOTONS OSCILLATE SYNCHRONOUSLY IN SAME PHASECOLLIMATED-NARROW BEAMMONOCHROMATICITY-WAVELENGTH IS LIMITED

CLINICAL APPLICATIONS

Used commonly for ocular, fissure surgery, genitourinary,oropharyngeal and endoscopic laryngeal surgeries.

• Provides good haemostasis.• Rapid healing and minimal scarring.• Surgical precision and preservation of normal

tissue.• Lesser post op‐ oedema and pain.

SOLID-RUBY/YAG

GAS-CO2 ,HELIUM

EXCIMER(DIMERS IN EXCITED STATE)-XE,ARGON,BROMINE,FLOURINE

DYE-ORGANIC DYE(CARCINOGENS)

DIODE(EXCITATION WITH LIGHT/ELECTRICAL SOURCE)-LASER POINTERS/DVD/CD

TYPES OF LASERS IN CLINICAL PRACTICE

I KNOW IT IS BORING ,PLZ GET UP AND BEAR WITH ME FOR SOMETIME.

DIFFERENT WAVELENGTHS OF LASER LIGHT CAUSE DIFFERENT PATTERNS OF TISSUE DESTRUCTION DEPENDING ON LASER PARAMETERS AND TISSUE FACTORS.(eg CO2 long wavelength superficially absorbed)

Image

h t i l d ith

Nd‐YAG NEAR 1060 ‐Transmitted through fibre ‐Can cause retinal

LASER MED IUM

COLOUR WAVE LENGTH (nm)

FEATURES HAZARDS AND PREVENTION

CO2 FAR INFRA

10,600 ‐invisible, needs aiming laser‐requires operating microscope

‐large amount of laser plume

RED ‐highly water absorbent‐vapourises superficial layers‐precision cuts, good

‐OT contamination‐Ocular injury tocornea. Can be

haemostasis, less oedema withalmost no injury tosurrounding tissue

prevented with useof clear plastic orglass eyewear.

Ho‐YAG

INFRA RED

INFRA 2060

optic bundles.‐Penetrates up to 2 to 6 mm‐Readily absorbed bypigmented tissue

‐Excellent absorption in water

damage. Protect with opaque green eyewear.‐Delayed oedema and bleeding‐Can cause venous embolisation in

RED rich tissues. Used for nasal and tonsillar surgeries.

tracheal surgeries.

BLUE 488 ‐ Strongly absorbed by Use special

KTP GREEN 532 ‐Used with flexible fibre optic

‐Retinal damage can

‐Absorbed by pigmentedtissues.‐Used for highly vascularareas such as tongue, noseand deep structures intrachea.

occur. Usespecial glasseswith red filter.

ARGON GREEN 515 ‐Transmitted with fibre optic bundles.

‐ Can cause retinal damage.

pigmented tissues like haemoglobin and melanin.

opaque orange eyewear.

BIOLOGICAL EFFECTS

ELECTROMAGNETIC EFFECT-E .g, LITHOTRIPSY

THERMAL EFFECT-ELECTROCAUTERY,HARMONIC

PHOTOABLATIVE-EG CORNEAL SX,PROSTATE SX

PHOTOCHEMICAL EFFECT-LEAST STUDIED , EFFECT ON

ETC,ENZYME SYSTEMS,OXIDATION STATES ETC.

granulomas

SHARED laryngeotracheal

.

INDICATIONS• Benign growth nodule‐ s, polyps, cysts,

• Vocal cord dysfunction• Malignant growths• Recurrent respiratory papillomatosis

Laryngeotracheal surgeries involves a SHARED AIRWAY and thus cooperation between surgeon and anesthesiologist is must.

ROLE OF ANAESTHESIOLOGISTS

MAINTAIN OXYGENATION.REMOVAL OF CO2 KEEP PATIENT ANAESTHETISED

PROVIDINGGOOD DEPTH OF ANAESTHESIA THROUGHOUT PROCEDURE

REDUCE RISK OF AIRWAY FIRE DEAL WITH CRISIS AND REDUCE

POST OPERATIVE COMPLICATIONS

PREOPERATIVE ASSESSMENT AND PREPARATION

DETAILED HISTORY‐ difficulty in breathing, swallowing, snoring, stridor,

wheezing, difficulty in clearing secretions, change in voice, best breathing position and breathing pattern during sleep.

‐ Try to get an idea of the location, size, extent, mobility of lesion and the extent of airway compromise.

‐ Older debilitated patients with long standing airway compromise are likely to have CVS and RS involvement and should be evaluated for same.

‐Obesity, history of acid reflux and hiatus should also be noted as it increases risk of aspiration.

EVALUATION• PREVIOUS AIRWAY ASSESSMENT WITH DIRECT

OR INDIRECT LARYNGOSCOPY

• IMAGING WITH CHEST RADIOGRAPHY, CT SCAN OR MRI OF SITE OF LESION

Before providing anaesthesia, determine the possibility airflow obstruction post induction and site of lesion whether supraglottic, glottic or subglottic.

PREOPERATIVE PREPARATION• Avoid sedative premedication. In very anxious

patients consider titrated doses of midazolam with monitoring. Assurance and counselling is best.

• Can consider antisialogouge like glycopyrrolate for drying up secretions and to counter vagal bradycardia due to DL or ML scopy

• Always have a difficult airway cart ready, with rigid bronchoscope, jet ventilator and tracheostomy tray on stand by.

• Other standard precautions for LASER surgeries.

INDUCTION OPTIONS

IV PROPOFOL /SEVOFLURANE

+/- MUSCLE RELAXATION

SHORT ACTING OPIODS

INDUCTIONCAN BE INHALATIONAL OR INTRAVENOUS

IV with propofol, short acting opioid and muscle relaxation if reqd

MONITORINGROUTINE MONITORING• ECG, HR• NIBP• Spo2, EtCO2• Temperature

ADDITIONAL• Airway pressures• Invasive monitoring

TYPES OF VENTILATION

Intubation Non intubation techniques techniques

INTER ‐ SPONT INSUFF ‐ ‐ JET MITTENT ANEOUS LATION VENTIL APNOEA VENTILATION ATION

1. SUPRAGLOTTIC2. SUBGLOTTIC3. TRANSTRACHEAL4. HFJV

CLOSED VENTILATION WITH INTUBATIONHOW TO SECURE AIRWAY?

1. small growth‐ routine tracheal intubation after induction with small size tubes2. moderate growth with possibility of worsening of airway obstruction‐ awake intubation/tracheostomy under LA with limited premedication3. large growth, impinging on airway ‐

preoperative tracheostomy electively, no premedication

MAY BE NEEDED DUE TO• ADEQUATE MAINTAINANCE

• HIGHER RESISTANCE,AGENTS

PROS AND CONS OF INTUBATION

ADVANTAGES DISADVANTAGES• ROUTINE TECHNIQUE • LIMITS SURGICAL ACCESS• AIRWAY PROTECTION AND VISIBILITY

• CONTROL OF VENTILATION HIGH AIRWAY PRESSURES

OF DEPTH WITH VOLATILE SMALLER TUBE SIZE

• MONITOR ETCO2 DIFFICULT SUCTIONING,

OCCLUSION• RISK OF AIRWAY FIRE

SPONTANEOUS VENTILATIONINDUCTION‐ Inhalational with sevoflurane or IV with

propofol and short acting opioids.VENTILATION‐ 100% O2 by face maskTopical LA applied to VC by DlscopyOnce adequate depth ‐ procedure is doneADVANTAGES- excellent visualisation of field, can

evaluated VC functionDISADVANTAGES‐ only for short procedures, depth of

anaesthesia not consistent, risk of aspiration, surgical field not immobile

INSUFFLATION TECHNIQUEROUTES small‐ catheter in nasopharynx,

nasopharyngeal airway, sidearm or channel of laryngoscope

ADVANTAGES‐ allows us to provide continuous O2 supply to patient. Can also be used to provide volatile agents.

DISADVANTAGES‐ no control over ventilation, risk of aspiration, gastric distension, OT pollution, inconsistent depth

• Induction followed by endotracheal tube insertion.INTERMITTENT APNOEA TECHNIQUEPatient ventilated till SpO2 100%

• ETT removed from airway‐ surgeon takes over for procedure.

• Watch O2 sats when‐ it falls to predetermined level, ETT reinserted and patient ventilated till SPO2 back to 100%

• PROS-excellent visibility of field and safety in laser• CONS limits‐ surgical time, aspiration risk,

inconsistent depth, inadequate ventilation, trauma due to multiple intubations, can’t be used in debilitated patients or those with cardio‐respiratory compromise and decreased FRC

• Always monitor chest wall motion

JET VENTILATION• Gas under high pressure

supplied to airway via a 16 Gcatheter aligned with thelaryngoscope, that is open toambient air

• Ventilatory rate of 6 7/min‐ at 15‐

20 psi for adults and 5 10‐ psi forchildren. I:E ratio of 1.5:6 sec

for adequate inspiration and expiration.

inadequate ventilation

surgicalblown distal

Depth to be maintained by IV

barotraumaLess risk of barotrauma

SUPRAGLOTTIC V/S SUBGLOTTIC

Most commonly used Delivery of gas directly intoMalalignment can lead to trachea mo‐ re efficient

Blood, debris or tissue can be No vocal cord motion

Movement of vocal cords No time constraints for surgeryCant monitor ETCO2 100% O2 at 15 psi

drugs But higher risk of pulmonary

TRANSTRACHEAL JET VENTILATION• Percutaneous transtracheal

catheters through the cricothyroid membrane or trachea

Problems• Greatest risks of barotrauma of

all ventilation(>copd) pneumothorax/mediastinum.

• Blockage & KinkingInfection

• Bleeding

HIGH FREQUENCY JET VENTILATION• Ventilatory rates : about 100‐150 b/minute used• Tidal volume : <2 ml/kg• Allows a continuous expiratory flow of air,

enhancing the removal of fragments of blood and debris from the airway.

• Reduced peak and mean airway pressures with improved hemodynamic stability

• Enhanced diffusion and interregional mixing within the lungs resulting in more efficient ventilation

PROBLEMS WITH JET VENTILATION• Cannot be used in obese, COPD and Restrictive

lung disease patients• Avoided in severe obstructive pathologies in

which egress of exhaled air is not possible• Cannot use volatile agents for anaesthesia• Not possible to monitor ETCO2

• Intraoperative arrhythmias, aspiration, seeding of polyp into trachea.

• Postoperative laryngospasm, laryngeal oedema, stridor, pneumothorax and pneumomediastinum.

LASER HAZARDS and PRECAUTIONS

IMAGE

1.Atmospheric contamination – laser plume

2.Perforation of a vessels or organs

3.Airway fire

4.Air embolism

5.Inappropriate energy transfer

ATMOSPHERIC CONTAMINATION• Plume of smoke and fine particulates (mean size

0.31μm) deposi‐ ted in the alveoli

• Sensitive individuals: headaches, tearing, and nausea after inhalation. May be vector for viral infections

• Animal study: interstitial pneumonia, bronchiolitis, reduced muco‐ ciliary clearance, inflammation, emphysema

Prevention• smoke evacuator• high‐efficiency masks.

may a LASER system

Use Coolant gas‐

• CO2( cant coagulate vessel

several days later when of ventilation to washout CO2 when used inmaximal, with Nd‐YAG

Laser hazards

PERFORATION VENOUS AIR EMBOLISM

• Misdirected laser energy • Associated with Nd‐YAG

Perforate a large blood vessel

>5mm) lasers preferred.• LASER‐induced Absorbed faster from

pneumothorax vessels• Perforation may occur • Keep higher frequency

oedema and necrosis are

Lasers laparoscopic and GU.

INAPPROPRIATE ENERGY TRANSFER• Incidentally pressing the LASER control trigger• Tissue damage outside of surgical site

• Also D‐ rape fires‐Eye damage (patient or other medical staff)‐Endotracheal tube damage,‐ fires

PRECAUTIONS: WARNING SIGN OUTSIDE OT1. Use lasers in short bursts and low power.2. Cover eyes with opaque saline soaked knits or metal shields.

Special eyewear for OT personnel

3. Wet drapes to cover head and chest.4. Saline soaked pledgets to be placed around tube and area of

surgery.5. Windows to be covered with opaque drapes

finish.wrap and outer Teflon coat.

Small uncuffed and large sizesCuff contains methylene bluecrystals.

SPECIAL LASER TUBESLASER SHIELD II LASER FLEX TUBE

Stainless steel with smoothSilicone with inner aluminium plastic surface and matte

For CO2/KTP For CO2 and KTP LASERS.

with 2 cuffs available.

NORTON TUBE BIVONA FOAM CUFF LASER TUBE

foam sponge with siliconeUncuffed, externalattached.

cuff can be

Retains shape when ruptured but

SPECIAL LASER TUBES

Spiral wound metal tube with Aluminium and silicone spiralstainless steel connector. with silicone covering.

Reusable flexible and thick. Self inflating cuff of polyurethane envelope.

For CO2, KTP and Nd‐YAG can no longer be deflated forFlexible coils not airtight‐ can removal.cause leak Only for CO2 LASERS.

TUBE WRAPS:TUBE

1. MEROCEL WRAP LASER‐ GUARDcopper foil and water absorbent

sponge.For CO2 and KTP LASERS

SPECIAL LASER TUBESSHERIDAN LASER TRACHEAL

Can be used with CO2, KTP and Nd‐Red rubber tube wrapped with YAG

fabric. FDA approved‐ metal foilThick wall and high pressure cuff laminated to a synthetic

2. Aluminium and copper foils.

LASER TUBUSWhite rubber tube with cuff within

cuff design.

Inner cuff is filled with air and outer cuff with saline.

• Trauma to mucosa• Paint the tube

benzoin.

with

• No protection of cuff

60 degree. • Add thickness to tube

junction tube

it adds 2 mm to tube• Wrapping in spiral with

of the cuff

SPECIAL LASER TUBESMETHOD OF WRAPPING DISADVANTAGES OF TUBES

medical adhesive such as • Reflect laser beam

• Cut the end of the tape at Expensive

• Start wrapping from • Airway obstruction proximal

end of cuff • Limited surgical access as

30% -50% overlap thickness.

• It includes inflation tube

SPE

SPECIAL LASER TUBES

COVIDIEN LASER ORAL/NASAL TUBE WITH TWO CUFFS(LASER FLEX) CO2/KTP LASER.

OTHER FACTS-

TO SAVE ETT REFLECTIVE TAPE TO REFLECT LIGHT

CUFF FILLED WITH METHYLENE BLUE TO DETECT LEAK

CU/AL-NOT FDA APPROVED,MEROCEL-FDA APPROVED

CHOOSE TUBE 1-2MM SMALLER IN SIZE .

LASER RISK CLASSIFICATION• CLASS 1 : Considerably safe. Lasers that are

completely enclosed or emit extremely low output.• CLASS 2 : Low risk. Equivalent risk to staring for long

directly at the sun or at bright lights, which can lead to central retinal injury.

• CLASS 3 : Lasers with power above 1 mW3A : 1 5‐ mW. Moderate hazard

3B : 5 500 ‐ mW . Even momentary viewing can be hazardous to eyes and skin.

• CLASS 4 : Continuous wave laser with power output above 500 mW . Serious skin, eye and fire hazard.

WARNING SIGNS OUTSIDE OTEYE PROTECCTION-FOR PATIENT AND WORKING PERSONNEL.

LASER PLUME-EVACUATOR MACHINES AND HIGH EFFECIENCY MASKS.

INSTRUMENTS –MATT FINISH TO AVOID REFLECTION.

MUCOUS MEMBRANE ADJACENT TO SX SITE SHOULD BE COVERED WITH SALINE SOAKED GAUZE.

SURGICAL DRAPES SHOULD BE FLAME RESISTANT

PREVENTIVE MEASURES AGAINST FIRE MUST BE READY LIKE CO2 EXTINGUISHER,WATER.

SAFETY MEASURES IN LASER SURGERIES

power and in short pulses

AIRWAY FIRE PROTOCOL• Use lowest FiO2 less‐ than 40 %• Air preferred to N2O• Avoid tubes for shortprocedures

• Limit laser output to lowest

• Activate only when laser fibre tip is visible and clear of ETT• Use wet drapes to cover patientshair and chest

• saline filled 50 cc syringe to bekept ready

• nearest source of cold water and fire extinguisher should be known.

AIRWAY FIRE PROTOCOL-4 E’SExtract / Eliminate/ Extinguish• Put out fire – flood field with saline• Remove energy source – stop LASER• Remove oxidant source – disconnect circuit, stop ventilation &gases

• Remove fuel source (blowtorch effect)– extubate and remove burning fragmentsEvaluate• Review airway – ensure no burning fragments• Oxygenate – 100% oxygen by bag and mask•Review damage flexible or rigid bronchoscopy,chestXray may be needed, bronchial lavage for fragments• Establish airway – re i‐ ntubate, laryngeal mask airway or jet• Severe airway damage – tracheostomy or oral intubation, ICUadmission, controlled ventilation and high dose steroids.

AND PREVENTION PROTOCOL

TO SUMMARISE

PROTOCOL

TYPES OF LASERS

AND EFFECTS

ASSESSMENT

PREPARATIONE.g.. CO2, KTP, Nd‐YAG, Argon INDUCTION

LASER HAZARDS AIRWAY FIREAND PREVENTION

AIRWAY MANAGEMENT WITH TYPES OF VENTILATION

(SPECIAL MENTION OF LASER TUBES)