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