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:




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:




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)





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)



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.