Lasers

Question 1

What is a laser

Answer 1

Light amplification by stimulated emission of radiation
קרן עור:
1. ממוקד
2. בעוצמה גבוהה
3. מאורגן

Question 2

How does a laser work

Answer 2

2 mirrors and a cell (תא) filled with some medium (argon, KTP, CO2) stimulated by an external source of power

Question 3

What are the parameters that can be controlled by the surgeon?

Answer 3

1. Power (עוצמה)
2. Time of exposure
3. Spot size

Question 4

What are the effects of laser on tissues?

Answer 4

STAR
1. Scattering –> inverse relation to wavelength
2. Transmission
3. Absorption –> most relevant
4. Refraction

Question 5

How are lasers classified?

Answer 5

According to their wavelength
400 - 1400nm: visible
< 400: ultraviolet
> 1400: infrared

Question 6

Argon laser

Answer 6

Visible
432nm
Absorbed by hemoglobin and pigmented tissues
Used in superficial vascular lesions
When used in stapedotomy a drip of blood has to be added for absorption
Photoangiolytic

Question 7

KTP laser

Answer 7

500nm
Similar as argon

Question 8

Pulse Dyed Laser (PDL)

Answer 8

585nm
Similar to argon and KTP

Question 9

Laser Nd: YAG

Answer 9

1000nm
Near Infrared
Deep penetrance thorough blood and pigmented tissues
Used for lesions of the tracheobronchial tree
Can be adapted to a rigid scope and a suction system

Question 10

CO2 laser

Answer 10

10k nm
Infrared
Absorbed in water
Because its invisible it must be used with a micromanipulator and helium light spot (pointer)
Used in laryngology, procedures in the oral mucosa

Question 11

How can we avoid thermal diffusion and lateral thermal diffusion?

Answer 11

Pulsed lasers deliver large quantities of energy in a short period of time

Question 12

Eye protection during laser surgery

Answer 12

1. Visible and near infrared lasers (400 - 1400 nm) cause damage to the retina. All the OR personnel, including the patient, should wear protective blue or green eyeglasses
2. Infrared lasers (CO2) cause damage to the cornea. The surgeon doesn’t need eye protection, the patient must wear saline moistened eye pads, personnel should wear protective eyeglasses with side protection

Question 13

Skin protection

Answer 13

The patient’s skin and mucous membranes outside of the surgical field should be covered with a double layer of saline saturated surgical towels

Question 14

Smoke evacuation

Answer 14

2 separate suction systems.
One to suction smoke and steam from the operative field and another for aspirating blood and mucous.
When the anesthesia gas is open suction should be intermittent to keep oxygen at a safe level

Question 15

How to avoid an airway fire?

Answer 15

Keep forced inspiratory oxygen less than 35-40%
Use helium or nitrogen but NO nitrous oxide
Use laser tube, cuff inflated with methylene blue, saline saturated cottonoids above the cuff

Question 16

What to do in case of an airway fire?

Answer 16

1. Stop ventilation immediately
2. Withdraw tube while flushing it down with saline
3. Re establish airway
4. Bronchoscopy to evaluate damage
5. Steroids IV (*)
6. Keep the patient intubated
7. Daily bronchoscopies until extubation when the airway is stable