Card Set Information
When operating lasers, what three variables are set by the physician?
power (measured in watts)
spot size (measured in millimeters)
exposure time (measured in seconds)
How does scatter impact the effect of the laser?
Scattering tends to spread the laser energy over a larger surface area of tissue, but it limits the penetration depth. Light of shorter wavelength has greater scatter.
What is a strategy for minimizing thermal collateral damage?
To minimize lateral thermal damage from thermal diffusion, the tissue should be ablated with a short laser pulse.
Describe the properties of a Neodymium:Yttrium-Aluminum-Garnet (Nd:YAG) Laser.
wavelength of 1.064 µm in the near infrared range
can be transmitted through clear liquids, facilitating its use in the eye
Absorption is slightly color dependent, with increased absorption in darkly pigmented tissues and char
strong scattering and deep penetration makes precise control impossible.
Good for coagulationp
Describe the properties of Carbon Dioxide (CO2) Laser.
wavelength of 10.6 µm in the infrared (invisible) range
strongly absorbed by pure, homogeneous water and by all biologic tissues high in water content.
The extinction length of this wavelength is about 0.03 mm in water and in soft tissue.
Reflection and scattering are negligible.
absorption of the radiant energy produced by the CO2 laser is independent of tissue color
the thermal effects produced by this wavelength on adjacent nontarget tissues are minimal
Describe the properties of the Potassium-Titanyl-Phosphate (KTP) Laser
532 nm comparable to Argon
scattering and absorption by skin pigments when using the KTP laser are nearly the same as for the Ar laser
the KTP laser light is more strongly absorbed by hemoglobin
Describe the properties of 585-nm Pulsed Dye Laser
585-nm pulsed dye laser (PDL)
used mainly as a photoangiolytic laser for laryngeal applications.
The targets oxyhemoglobin, which has an absorption peak of 571 nm.
absorbed by intraluminal blood of vascular lesions such as papilloma, vascular polyps, vocal fold ectasias and varices.
PDL causes involution of the lesion through disruption of the vascular supply rather than immediate removal of the lesion.
Which protective glasses are worn with which laser?
: clear lenses
What do you do In the event of tube ignition during a laser airway procedure?
ventilation must be stopped immediately and the tube withdrawn simultaneously as saline is flushed down the endotracheal tube.
reestablish airway immediately
bronchoscopy performed to assess the degree of injury.
Intravenous steroids may be delivered and the patient should remain intubated; repeat bronchoscopy should be performed daily until it is established that the airway is stable.