BY
Azza Lotfy
Ass. Lect. Of Anesthesia & ICU
LASER
Light Amplification of Stimulated
Emission of Radiation
Physical principles of laser

Production of laser (Laser system hardware):
Physical principles of laser
Characters of Laser beam :

Monochromatic: one wave length)

Coherent: (oscillate in the same phase)

Collimated: (exist as a narrow, parallel beam)
Effect of Laser on tissues:
Laser factors:

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Wavelength
Power density
Duration
Tissue factors:

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Absorption
Thermal conductivity
Local circulation
Scatter
Types of medical Laser:
Laser media
Color
Wavelength
(nm)
Typical application
Carbon dioxide
Far infrared
10.600
General, cutting
Nd: YAG
Near
infrared
1.064
General, coagulation
KTP:YAG
Green
532
General,
pigmented lesions
Argon
Green
514
Vascular,
pigmented lesions
Xenon fluoride
Ultraviolet
351
Cornea, angioplasty
Advantage and clinical uses of
laser:

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Scalpel and electro coagulator.
Allow precise microsurgery.
Relatively dry field.
Less postoperative edema and
pain with lower infection rate.
Disadvantages of laser (hazard
of laser)


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Atmospheric contamination ” laser
plume”
Misdirection of laser energy
Gas embolism
Energy transfer to an inappropriate
location
Fire and explosion
Disadvantages of laser (hazard of laser)
Atmospheric contamination ” laser
plume”:
1.
2.
3.
4.
5.
Interstitial pneumonia.
Bronchiolitis.
Reduced mucociliary clearance, inflammation.
Emphysema.
Plume can be mutagenic, teratogenic or vector of
viral infection.
Disadvantages of laser (hazard of laser)

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Misdirection of laser energy:
perforation of viscous or large blood vessels.
Gas embolism:
Venous gas embolism when laparoscopic or
hysteroscopic laser surgery are reported.
Energy transfer to an inappropriate location:
Eye damage (corneal opacities, retinal damage);
Skin damage (from erythema to blisters or charring).

Fire and explosion:
Laser contact with flammable material such as
rubber or plastic may cause fire and explosion.
Airway Fire


1.
2.
3.
Incidence; 0.5% - 1.5%
Predisposing factors;
Flammable materials (ETT).
Source of ignition (Laser beam).
Gas support combustion (O2).
Airway Fire

Fire may be:


On external surface of ETT cause local
thermal destruction.
Blowtorch like fire.
Airway Fire
Approaches to reduce the incidence of
airway fire:
1. Reduction of the flammability of ETT.
2. Removal of flammable material from the
airway by using :


Venturi jet ventilation;
Intermittent extubation with or without
apnea.
3. Reduction of the available oxygen
content to the minimum required for
reasonable arterial saturation.
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 protection
Expensive
Laser resistant tracheal tube

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a. The Norton tube:
Reusable
Stainless steel
Flexible tube
No cuff
Laser resistant tracheal tube
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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
Laser resistant tracheal tube
d. The Bivona Fome-Cuff laser tube:
 Designed to solve the perforated-cuff-deflationproblem.
 It consists of an aluminum wrapped silicone
tube with unique self inflating foam sponge
filled cuff which prevent deflation after
puncture.
Reduction of the flammability of ETT:
B. Wrapped standard tubes:


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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).
Wrapped standard tubes

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

Mechanism of wrapping:
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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.
Approaches to reduce the incidence of
airway fire:
2.
Removal of flammable material from air way:
a) Jet ventilation:
• Use high pressure oxygen source directed at
the glottis through small metal tube such as
ventilating bronchoscope or 12 gauge blunt
needle.
• it permit entrainment of oxygen enriched
air during inspiration and escape of carbon
dioxide and exhaust gases during expiration.
Removal of flammable material from air way
Advantage:
 Adequate ventilation without introducing
flammable material.
 No obstacle to the surgical field.
Disadvantage:
 Barotrauma
 Pneumothorax
 Restriction to only anesthetic intravenous
agents
 Gastric distention
 Relative requirement for compliant lungs
Removal of flammable material from air way
b) Intermittent extubation with or without apnea:
 Intermittent extubation by the surgeon.
 Combined with spontaneous ventilation or
intermittent apnea.
 General anesthesia provided by nasal
insufflations of potent inhaled anesthetic or
by use of intravenous anesthetic agent.
Approaches to reduce the incidence of
airway fire:
3.
Reduction of the available oxygen content:
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Oxygen and nitrous are powerful oxidizer.
Reduce the inspired oxygen concentration
to less then 0.40.
Avoiding diluting oxygen with nitrous .
Dilute with helium.
Airway fire protocol
(Management of airway fire)
1.
2.
3.
4.
Communication and recognition.
Stop ventilation, remove ETT and disconnect
breathing circuit from anesthesia machine to:
 Remove flame
 Remove the retained heat in the tube
 Stop flow of enriched gas
Flood the surgical field with water.
Ventilate the patient with 100% oxygen via
face mask.
Airway fire protocol
(Management of airway fire)
5.
6.
7.
8.
Assess the damage:
 Examine the patient face and oropharynx
 Rigid bronchoscope.
 Direct laryngoscope.
Monitor the patient with pulse oximetry, serial
ABG and chest X ray.
Reintubate the patient or perform
trachestomy as needed.
Use ventilatory support, steroid and antibiotic
as needed.
Protective safety measure during laser
surgery
1.
2.
Warning signs
Eye protection:
 For the patient: eye should be taped closed
and covered with opaque saline swabs or
metal shield.
 For the working personals: wear safety
goggles or lens specific for the laser wave
length in use.
3. For laser plume:
 use efficient smoke evacuator at the
surgical site.
 Use special high efficiency mask.
Protective safety measure during laser
surgery
4. Skin protection:
The patient ‘skin, mucous membrane and
teeth adjacent to operative field should be
covered with saline soaked gauze.
5. Surgical drapes made of flame resistant or
waterproof material.
6. Preventive measures against fire and
explosion must be ready.
FINALLY

Never are cooperation and
communication between surgeon and
anesthesiologist more important than
during LASER surgery, it is the key to
managing a crisis such as air way fire
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High pressure oxygen source
Venturi effect (entrainment of air).
Active insipration
Passive expiration