LASER IN ANAESTHESIA

INTRODUCTION:

1. LASER is an acronym denied from phrase Light Amplification by Stimulated Emission of Radiation.

1. Photoradiation (beam of light)
2. Ionising radiation (X-rays)

1. HISTORY :

1. In 1864 Maxwell explained the light is electromagnetic wave which propagate at about 299 > 92458 m/S (millions)
2. Max Planck discovered photoelectric effect i.e. light of certain colour causes metal to eject electrons at rate proportional to the brightness of light. 1^st step to laser physics.
3. In 1905 Einstein established the article basis for laser. He explained electromagnetic energy radiation (i.e. light, radio X-rays) consists of photons. Photons possess wave like and particle like property and travel at constant speed about 300 million M/s.

• • Ultraviolet longer wave lengths. Inframed upto 1930 physical principles were known.
  • In 1958 – the technology for pumping up electrons to active stimulated emission was introduced.

• • In 1960 – Maiman produced pulsed laser operation at 694 nm, Ruby red visible 1^st working loser.

• • In 1960 - Patel reported Inframed Laser action in pure CO2.

• • In 1969 - Polyani developed endoscopic and micromanipulator seam delivery system.

• • In 1976 – an investigation of contents of Laser plums arising from Co2 Laser incision reported the absence of any visible cells. This cleared the path for its use in malignant tumour

3. LESER PRINCIPLE :

1. 1. Its highly monochromatic. i. In consists of wide
   2. It consist of photons that Spectrum of wave

      have well defined very length.

      narrow band of wavelength.

   3. Coherent ii. Randomly phased
   4. i.e. all wave in phase electro-

      magnetic wave oscillate Synchronously.

   5. Collimated (Waves in iii. Spreads out in all parallel). Direction from point

These three characteristics allow Laser :

1. To generate intense light beam.

2. Send efficiently and accurally through Lenses.

3. Deliver intense energy to small target site.

Energy produced can be conceptualised in terms of photons of light. An electron of an atom occupies certain locations called orbits.

1. The lowest energy of an atom is associated with normal orbit of an electron. It is termed ground stage. The orbit has different energy, thus orbits farthest from nucleus having greater energy.

2. The energy levels at higher level are termed excited states.

An electron can move from one orbit to another. When moves to higher orbit absorb energy or to lowest emit energy the amount of energy exactly equal to the difference is energy between two orbits. Photon energy captured by electrons into higher orbital is called stimulated absorption in converse process – electron drops to a lowest orbital where photon carry away excess energy is called spontaneous emission. Normally electron is much more engaged in spontaneous emission.

STIMULATED EMISSION : Is the key to laser action for this process a photon of a particular wave length must collide with an atoms ready for spoulanous omissions at that wave length.

1. STIMULATED ABSORPTION :
2. A photon striking electron may transfer energy and

   An electron moves to higher orbit i.e. higher energy orbital.

3. SPONTANEOUS EMISSION :
4. PASTE DIAGRAM

   An electron is an orbit higher than ground state may spontaneously loose energy in the form of enlisted photons.

5. STIMULATED EMISSION :

4. LASER SYSTEM DEVICE :

1. 1. Tube containing the laser medium.
   2. Resonating (Reflecting) mirrors.
   3. Energy source to excite atom of laser medium.

a. LASER MEDIUM :

1. 1. gaseous
2. a. Co2,
3. b. argon,
4. c. Krypton,
5. d. Helium neon.

   2. Solid rods of Laser passive material

   a. Chromium

   b. Neodymium

   c. Synthetic gem crystal

1. 1. Glass
   2. Liquid dye (organic)
   3. Semiconductors
   4. Excimer – i.e. excited dimer, Krypton, Xenon argon /fluoride or chloride photons of very high energy.

These medium deternunery

1. 1. Name of Laser.
   2. Wave length

1. 1. Tube containing laser medium.
   2. Reflecting two mirror on either side of tube

1. 1. One mirror fully reflecting.
   2. Other parallel reflective and transmissible.

1. 1. Energy source

In sequence of events in the production of laser beam

The Laser beam is available in two modes :

1. 1. Continuous mode
   2. Pulsed mode

4. CATEGORIES OF LASER :

1. 1. Water absorbed :
   2. Thermal effect e.g. Co2 Laser.
   3. Pigment absorbed :
   4. Photochemical

      e.g. Nd – YAG, Argon

   5. Absorbed by specific organic material within living tissue
   6. e.g. Krypton gas Laser
   7. Thermoacuoustic
   8. Abaltive photo decomposition

choice of laser based on following advantages

1. Tissue can be altered remotelling.

1. 1. Microsurgery with use of microscope.
   2. Easy transmission through endoscopes.
   3. Selective destruction and tissue.

LASERS USED IN MEDICINE AND SURGERY :

LASER MEDIUM COLOUR WAVE APPLICATION

LENGTH

2. Nd-YAG Near Infraned 1,060 Coagulative Haemostasis

(Solid)

3. Nd-YAG Green 532 General pigment Lesions

KTP

4. ARGON Green 514 Vascular pigment Lesions

5. Helium Red 632 Aiming beam

Neon

6. Ruby Red 699 Tahoo, Nevi

7. Organic Red /Yellow 632 Phototh orapy dermatilogy

dye oplthalnology

8. Krypton Yellow 568 Relive

9. Argon Blue 488 Vascular

Pigmented Lesions

The effect that a particular beam depends on its 1. Wave length 2. Power density 3. Duration.

As lining tissue contain complex aqueous solution and variety of molecules which absorb light. For particular wavelength of light absorbed and converted to heat in the target tissue wavelength measured in – nm.

Power density i.e. amount of power (energy /se) per unit area arriving at surface expressed Watts Sq.Cu.m.

Loulu = Watts / Sq.cm/Se.

= 2500 calaries /Se.

Production of heating occurs at a rate of many thousand degree

e.g. Co2 Laser = 5000 Deg.C. /Se.

This is important in clinical application.

LASER MEDIUM COLOUR WAVE APPLICATION

LENGTH

10. Xenon Ultra 351 Cornea angloplasting
11. Fluonde Violet
12. Xenon Chloride - Do - 308 - Do –

12. Krypton Fluoride - Do - 248 - Do –

13. Krypton Chloride - Do - 222 - Do –

14. Argon Fluoride - Do - 193 - Do –

Interaction of Lasers with biological tissue :

Electromagnetic (radiation) falling on tissue, it is

1. reflected
2. absorbed
3. transmitted or both

Depending on rate of energy delivery power density, wave length

Absorption

Leading to Meating

Coagulation of protectivity

Inter cellular water expands

Vaporises

Cell rupture

Co2 Laser

1. Absorbed by water, blood biological tissue
2. Effective length – 0.03 mm.
3. It is shallowest protection ie. 200 um
4. Reflection and scattering wild
5. Oldema formation minimal

These properties make Co2 laser beam, most suitable as ‘Cutting tool’

At lowest output as coagulant tool (For haemotasim)

Nd-YAG

1. Weakly absorbed by water
2. Deepest penetration
3. Scattering through volume of tissue
4. Greater volume of tissue involvement
5. Less vaporisation
6. Move thermal effect coagulation

Hence called as coagulant of tissue.

Absorbed by pigments suitable for

1. Control of bleeding gestriz crosoms
2. Vascular Lesions
3. Polyps
4. Haemostasim cr. Vessels upto 5 mm.

Short wave length of this Laser allows the beams to be transmitted by fibre optic bundlers to reach in accessible part of body.

Ruby Laser :

Poorly absorbed except dark pigments

Argon & Krypton gas laser : Transmitted by water intensaly absorbed by Hb, so ability to penetrate skin, accular tissue. Hence, selective vascular coagulation. Pigmented Lesions.

Helium Neon :

Visible very low power output used for aiming.

NEVER APPLICATION OF LASER :

Holium and Thatium contribution with YAG short wave length

Water absorption

Application in ;

2. Orthroscopic soft Tissue
3. Intra nozal sinusous surgery
4. For dental application
5. Angioplasting replacing bypass surgery and balloon angioplasty.

CLINICAL APPLICATION ;

Lasers are uses as

1. Scalpels
2. Electro coagulant
3. Allows highly pressure micro surgery
4. Allows confined or difficult to reach sites.

Laser surgery is

1. dry
2. minimal heating of adjacent area cells
3. little formation of oedona
4. Near instantaneous sealing of small blood vesselous lymphatizs, even in presence of coagulating disorders.

However faster heating lower infeeling rate validated

SURGICAL APPLICATIONS :

1. Otolaryngology
2. Head and heck surgery
3. Gynacological surgery
4. Neuro surgery
5. Opthalmology
6. Urological
7. Plastic surgery

Most important role of anaesthenologist and otobaryngologist in surgical application of Laser, as air way is shared by both. In this field endoscopic laser surgery is employed to rename

1. Lasurgcal papilloma
2. Larugcal neo plastum
3. Larugcal webs
4. To reset sub glottic stenosm.
5. To reset sub glottic henarigiomal
6. Epiglottectomy

Hazards and general safety measures during Laser Surgery

1. Hazard to operating room persons

1. 1. Eye : Most susceptible tissue to injury by radiation Ruby and Argon Laser passes through coniea – max damage retina. Co2 – Laser absorbed first 200 Mm hazardous to cornea.

1. 1. It should fit around forehead
   2. Should protect Lateral margin of orbit.
   3. Clearly marked for appropriate Laser wave length.

PREVENTION :

1. 1. Use of fine filter to evacuate smoke.
   2. Use of special mask.

1. 1. Protection of eyes, nose, monstache, bead

Fire is most important factor due to its potential to cause previous damage.

Predisposing factors

1. ETF – red rubber portex – PVC tracheoustomy tube.
2. An atmosphere that supports computation – oxygen, air, N2O
3. Source of ignition – direct uninterrupted or prolonged.

RECOMMENDATION TO PREVENT FIRE HAZARDS :

1. Plastic material should not be used with Co2 laser.
2. O2 concentration – minimal and safe compatible with anaesthesia
3. Practice : 30%, oxygen & air.

   30%, oxygenic Helium.

4. Tube modification

1. 1. Aluminium foil wrapping spirally around the red rubber to be cut should not be covered cut should not be covered.

Advantages :

1. Red rubber tube move resistant to ignition.
2. Produces less debris and inflammation.

1. Smaller size tube used.
2. Al. Foil wrapping makes it bulkier.
3. Metallic foil does not alter protection from striking Nd-YAG.

2. Silicone trached tubes

3. CARD EN – Silicone rubber tube short cutted 5 mm. Two small rubber centimeter

which can be passed through local cord.

1. 1. One for jetting gas, and
   2. One for inflating the latex cut. Eatheter passed through local cards connected with wet coltanords used in micro laryngel surgery.

1. 1. Can be used instead of ETT.
   2. Amount of gas delivered to the trachea is not limited by inspiratary obstruction.

1. 1. Lathmeter provide small combustible material but if severed, parts may lost in the techno brochical free.

1. 1. Problem of fine overcomes.
   2. Leakage of gases through spiral, humidification, cooling.

Disadvantages :

1. 1. Thermal effect due to direct heating.
   2. Smaller size tube used.
   3. Hevier
   4. Traumatic
   5. Expensive
   6. Can not be used in paediatric cases.

Effects of Burns on the Airway effects of explosion depends on

1. 1. Magnitude of events.
   2. Severity of burn

• • Chemical response – access due to toxic PVC fumes.

1. 1. Due to turbulant gas flow which may cause vibration of vocal cords, tracheal wall, as well as deflation of lower beam.
   2. Damage of normal structure – due to inadverent overshoot or deflatias of laser beam.
   3. Damage due to unexpected coughing or movement.
   4. In laryngo – trachal tear - Increased into thorache pressure. Resulting.

1. 1. Pneumatic ray.
   2. Penero media stiram
   3. Pneuoperi cardum.

POLLUTION (tasur plumes)

1. . Fully acid esters 5. Etc.
2. can be considered on noxious particular of size range from 6.1 to 0.8mm.

Hazardous

1. Bronchosparma
2. Alveflar ocdena
3. Diflure affectasm

In open system or jet ventilation smoke is propelled to distal airway – none chanum

In closed system not transmitted technique of alternate phasing of ventilation /vaporization and suction redness pollution.

Technique of using

Suction channels on loryngoscope/broucho scope will reduce pollution of operation rom.

Regimen in the management of air way explosion

Primary emergency care

- Stop ventilation

- Disconnection oxygen

- Remove ETT

- Place oral way

- Ventilate with mask

Secondary emergency care

- Perform rigid brochos copy to remove large FB.

- Administer lavage to trachea.

Fiber optic brouchoscop to visualise small airway and remove small FB

and large to distal airway.

- Evaluate injury to tracheo brouchal free

- Remove framented mucosa and debris.

• • If necessary perform low tracheostong.

Teritiary emergency care

• • Administer anti bookes and short term steroids.
  • Provide high humidity air.

Subsequent management

• • Culture tracheral aspirate daily.
  • Perform endosecopy 3-5 days post burn to evaluate extent of injury.

Perform ventilation perfuses study x-ray chart review /tempgraph of respiratory free.

Early weaving of ventilation.

10. ANAESTHETIC MANAGEMENT :

1. 1. A general physical, systemic assessment and evaluation.
   2. Airway assessment which has prime importance

• • mouth opening
  • neck examination flexion and extension for difficulty of leryngoscopy and respiration pattern.
  • - Adequacy of ventilation degree of airway obstaction in larger lesiam such as
  • - partrilloma

• • ABG ANALYSIS

To extent to which the existing tensions has compromised cardeo –vascual and respiration station evaluation.

In long standing obstractive lesiam development of palmonay Hypertension leads two side failure

Sign Symptarm

DM Dyspnea

JVP Failigue

Liver

Spleen

Gedenia

1. 2. Ventricular fuclias evaluation in obstructive process of traeheo brouchural free. It needs increase in negaline intra theraese processure for adequate ventilaton.

According to this needs evaluation to take appropriate measure.

Investigation

• • Hb
  • Blood grouping
  • Drive test
  • Blood mea, electrotyte
  • X-ray chest
  • ECG
  • ABC analysis
  • SP investigation where needed i.e.DM, HT, CCF infection.

Pre operative admission must

• • Please advise MBM written consent.

Before start

• • Laser surgery is going on.

Premedication

• • In Alropne 0.6 mg / 1m.

• • BP
  • ECG
  • Pulse oximetry
  • End tidal CO2
  • Airway pressural

Sedalion and local anaesthesia

- advanced pulmonay malgna complicated by airway obstruction suitable Laser.

• • Nd-YAG.

Can take path of fiber optic pronchoscope.

Co2 Laser

Optical fiber do not transmit. Co2 laser hence require – tizid brouchoscope general anaerthesia required.

Pre-oxygenation

Agent to attenate CVS response.

Induction with sleeping dose of Inj. Thiopenton Na 2 to 3mg/kg.

Intasation with aid of in succingyl choline 1.5 to 2 mg/Kg.

Size of luse 6 to 7.5 mm. Al. Foil.

Wrapped Red rubber

Fixation of tuse as side of lesion.

Micro lareing scope passed tube reduem to move if required.

Intra operative Management

Deepar plane of anesthesia required.

• • Coughing
  • Bucking
  • Movemutary of vocal cords.
  • Adequate dose of long acting or inter mediate acting muscle relaxant.

Oxygention – with minimal ventilatory resume of FIO2 - 0.3

In absence of combustible matern NO and halogenerated inhaler agent can be used.

Total intravenum anaestheum with infusion of

2. Inj. Thropenton
4. Inj. Ketamine
6. Short acting narcolum

Can be used.

Ventilation

Choice of method ventilation and for maintain of airway depend on size of target lesion.

Co2 Laser - used with rigid brochoscope need access for surgeon.

Two methods

1. small cuffed ETT
2. Venturi jet ventilation.

1. In small cuffed ETT, if ventilation not maintained cuff inflated with coloured salive, methole blue cuff covered with wet coffonoids.

Venturi jet ventilation

1. achieved by rigid injector attached to baryngoscope and introducing below vocal folds into trachea.
2. Through rigid venti laly brouchosur distal tolesiam.
3. Through cardan jet ventilaly tube.

In jet ventilation –

Oxygen or oxygerum and N2O used from high pressure. Jet system controlled by variable pressure reduction value and gauge delivery system frequency of ventilation maintained by pneumatically or manually. (inflation pressure 20.25 PSI)

Adequacy of ventilation accused by

• • chest movement
  • breath sound
  • pulse oximetry
  • ET Co2.
  • ABG analysis.

Advantagous

• • Absence of tracheal hete.

• • Total access to surgon.

• • Improved CVS stability.

• • Reduced peak and mean airway pressure.

• • Avoidance of hypoxia and maintained hormocar

• • reduced sedalious requmual.

• • reduced risk of barotrauma.

Disadvantages :

• • specialised equipment required.
  • Expensive.
  • Danger of high pressure gas flow.
  • Monitory or ventilatry parameter difficult due to noise.
  • Humidification of inspired gass difficult.

Complication.