Anesthesia for Laser surgeries

1. ANAESTHESIA FOR LASER
SURGERIES
CHAIRPERSON : Dr .UMA (PROFESSOR)
MODERATOR : Dr . SANJEEV (ASST PROFESSOR)
PRESENTOR : Dr .K. SHARIKA (3rdYEAR PG)

2. OPERATING ROOM FIRES
 Lasers are highly effective and rapid
sources of fire
 Given the right fuel , ignition can occur
with O2 at 21%(room air)
 Ignition potential is amplified in the
presence of an enriched oxidizer
environment that may be either oxygen or
nitrous oxide

3. OPERATING ROOM FIRE
 The ignition and propagation of fire
requires a triad of components called
the “ FIRE TRIAD”
 IGNITION SOURCE : Laser
 OXIDIZERS : Oxygen , Nitrous oxide
 FUEL : ETT , Plastic drapes , alcohol
based preparation solutions , hair ,
skin ointments

4. INSPIRED OXIDIZERS
 Ignition is facilitated and combustion is
intense in oxidizer enriched environment with
use of either O2 or N2O
 In its resting state nitrous no free oxygen
 However , N2O easily exothermically
dissociates releasing oxygen and heat
 The ASA practice advisory for the prevention
and management of OR fires strongly agrees
that nitrous oxide should be avoided in
settings for high risk for fires

5. INSPIRED OXIDIZERS
 As the temperature of the environment increases
the required FiO2 to support combustion decreases
 The ASA practice advisory does not give a maximum
allowable FiO2 but advises to keep it as low as
clinically feasible to avoid hypoxia
 Most of the anaesthesiologists prefer an FiO2 of 0.3
 When available diluting O2 with helium is better
then air – nitrous mixture as helium has higher
thermal conductivity and can delay the ignition of
ETT
 Reducing inspired FiO2 can does not decrease the
risk until expired concentration also decreases which
can take time with low fresh gas flows

6. GENERAL ANAESTHESIA AND
AIRWAY FIRES
 When the surgical site is near the airway , it is
essential to consider the need for an ETT, the type
of tube to be used , oxygen enrichment plan and
mode of ventilation
 A few oxygenation-ventilation strategies :
1. Ventilating through a cuffed or tightly fitting ETT
2. Continuous or intermittent ventilation using a
ventilator
3. Intermittent apnoea technique with episodic
removal of ETT
4. Supraglottic or infraglottic catheter positioning
for jet ventilation

7.  ETT fire requires swift corrective measures
 If ignited and combustion breaches the ETT
with its centrally flowing reservoir of oxidizer
a “BLOWTORCH” scenario can occur
 The potential for far reaching thermal injury
to pulmonary tract exists
 Compounds of complete and partial
combustion like debris and toxic gases causes
further insult

8. MANAGEMENT OF AIRWAY FIRE
 PREVENTION AND PREPAREDNESS :
1. Keep the O2 concentration at 30% or less if
possible . Use an O2-air or O2-helium mixture
2. Avoid N2O
3. Use a laser safe ETT
4. Inflate the ETT cuff with dyed normal saline to
provide an early indication of cuff rupture
5. Have an extra ETT available for re intubation in
case fire occurs
6. Added protection may be achieved by using saline
soaked sponges around the tube
7. Notify the surgical team of any situation in which
high concentrations of O2 are being used

9. IN CASE OF AN AIRWAY FIRE
 Stop lasering. Stop ventilation
 Turn off O2
 Inform the surgical team and assign someone
to call for help
 Remove the burning ETT and drop it in a
bucket of water
 Put out the fire with an improvised fire
extinguisher
 A 50ml syringe should be pre loaded with
saline and the area of fire should be flushed
with it

10. WHEN THE FIRE IS EXTINGUISHED
 Ventilate the patient with 100% O2 via a face
mask or supra glottic airway
 When the patient is stable , asses the extent of
airway damage
 Debris and foreign bodies should be removed
 Re intubate the [patient if significant airway
damage is found
 Shift the patient to ICU
 Provide supportive therapy including ventilation
and antibiotics
 Extubate when appropriate
 Tracheostomy may be needed

11. ETT COMPOSITION AND
COMBUSTION RELATED
PROPERTIES
 Standard polyvinylchloride (PVC),red rubber and
silicon tubes are ignitable and require protection
measures
 PVC TUBES : PVC tubes absorb far infrared light
are vulnerable to CO2 laser
 Of all the ETTs , PVC is most readily ignitable,
deposits carbonaceous debris and caused most
severe burns and cellular damage
 The PVC tube produces toxic by products of
combustion like hydrochloric acid

12.  Energy from Nd:YAG and visible light is not
absorbed by clear PVC ETT
 RED RUBBER ETT : More ignition resistant
and produces less debris and tissue
inflammation
 SILICONE ETT : Took the longest time to
ignite but the finding of silica ash raised the
concern for remote development of silicosis

13. LASER RESISTANT ENDOTRACHEAL
TUBES
 Standard ETT may be rendered laser resistant
by wrapping them in protective material
 Laser resistant ETT are of 2 types
1) Non metallic core laser resistant ETT
2) Metallic core laser resistant ETT

14. NON METALLIC CORE LR-ETT
1) THE MEDTRONIC LASER SHEILD 2 : It is
intended for use with CO2 and KTP laser
 It is a silicone tube core wrapped with a
flexible aluminum overlay and topped by
flouroplastic layer
 It has a single silicone elastomer cuff
 It is specified to withstand 35000 W/cm2 of
CO2 laser or 11000 W/cm2 of KTP energy
for 3 min

15.  2) THE SHERIDAN LASERTRACH :
 Intended for CO2 and KTP LASER
 It is a red rubber tube with a copper foil
overlay
 It has a single unprotected cuff
 Can withstand 40W of continuous CO2
laser for 60 sec
 But it readily ignited with high power
Nd:YAG laser

16. 3)THE RUSCH LASERTUBUS
 Intended for use with all medical laser types
 It has a central tube of flexible white
rubber reinforced with corrugated copper
foil and absorbent sponge
 It has a dual cuff inside cuff system
 It can withstand CO2 laser at 20 watts for
40 seconds and Nd:YAG laser at 25 watts
for 90 seconds

17. METALLIC CORE LR-ETT
COVIDIEN LASER ORAL/NASAL
TRACHEAL TUBE DUAL CUFFED
(LASER FLEX)
 It is intended for use with CO2 and KTP laser.
 It has an air tight flexible armored stainless steel
shaft and two independent cuffs positioned in
series
 It can withstand CO2 laser at 69 watt for 1
minute
 But it is vulnerable to Nd:YAG laser at high
power

20. THANK
YOU