A&A Page 245


Flexible tube, placed inside trachea of an
anesthetized patient, used to transfer gases
directly from anesthesia machine to
patient’s lungs.
Usually after induction
Page
2

Patient airway is assured
◦ Free from obstruction

Artificial ventilation can be provided
◦ Flow of O2 and iso from the machine will fill the
reservoir bag, which can be used to provide a breath
◦ When should this be done other than emergencies?

Dead air space reduced  increase efficiency of
gas exchange
◦ Dead air space describes the breathing passages that
contain air but no gas exchange can occur
3

“Cuffed” ET tubes reduces the risk of
vomit/saliva/water being aspirated
◦ Where would water come from? Vomit?


Secretions can be removed with suction
catheter through the ET tube
Efficient delivery of inhalant anesthetics
◦ Gas rates can be lowered (safe personnel)
◦ Anesthetic gas stays in the system, not the sx suite

Drugs can be easily administered in
emergency
◦ Must give double the IV dosage

Difficult to intubate certain patients
◦ Brachycephalic, tiny animals, bull dogs

Overzealous efforts to intubate can
damage larynx, pharynx, soft palate
◦ Cats especially with small glottis


Blind intubation (esophagus)
Tubes can be inserted too far
 Ventilation of only one lung

Pressure necrosis from over inflation


PVC, red rubber, or silicone
Non-cuffed
◦ Used in birds/reptiles due to their
tracheal rings

Cuffed
◦ Balloon type structure on the lower half of tube
◦ Inflated with air in a syringe AFTER tube
has been placed in the trachea
◦ Need a designated “cuff inflator”
◦
Murphy eye-beveled, with
a side hole
 Positive
pressure ventilation
 Easier achievement of anesthesia
◦ P isn’t breathing in room air too
 Prevent
foreign material from
entering lungs
 Less waste gases in room
*Inflating the cuff should not take the
place of using a larger tube
Blade
Light source
Handle
Responsible for
maintenance:
batteries/charging
and light bulbs
DIAMETER
 Should be a snug, easy fit
◦ Should not “fall” in OR be forced into trachea
◦ The cuff being inflated will “seal” the trachea

General ideas:
CATS = 3.0-4.5mm
DOGS = based on weight (table in A&A book)
Remember: 20 kg = 9.5-10 mm



Weight based is a guideline
Always prep 3 tubes (choice,1 smaller, 1 bigger)
Brachycephalics may need smaller than you think
◦ Long soft palate with extra tissue and narrow tracheas
Use width of space between the
nostrils as a guide
LENGTH
 Extend from the tip of the nose to the thoracic
inlet
◦ ABOVE THE TRACHEAL BIFURCATION

If you extend into only one lung:
◦ Hypoventilation and hypoxemia
???
If you extend tube too far past
patient’s nose
Increased dead space


Check several tubes for loose connectors,
excessive wear, cuff leaks, debris
Cuff leak check: inflate cuff fully and let it sit
Remember to deflate cuff completely prior to
intubation

Apply lubrication-
very small amount and optional
◦ Larger tubes – KY jelly or saliva
 Do not allow it to dry on tube
◦ Smaller tubes (<4.0mm) – water or saliva

Check patient jaw tone
◦ Swallow reflex
1. Visual



Preferred technique for dog and cat
Direct visualization of larynx minimizes
possibility of traumatic or improper intubation
Position: Sternal, Dorsal, Lateral recumbency
◦ Position is preference
Assistant holds hand placed on the muzzle
with fingers behind front canine teeth (like
you would for pilling) pulling upward to open
the mouth
 Neck should be slightly extended and in line
with body
 Pull out tongue to
visualize back of throat

◦ May need gauze to
hold tongue- slippery
14

Tongue is pulled forward and off to the side, then
held in place with thumb – moves epiglottis
forward and down
◦ Tongue can be held by you or restrainer



Move soft palate up and out of the way with ET
tube and at the same time…
Move epiglottis down out of the way with the tube
– this brings tracheal opening into view
Under direct vision, tube is passed through
tracheal opening
Tech note: You may need to wait for a breath
or stimulate animal’s body to inhale to see opening
RIGHT HANDED PERSON




Hold laryngoscope w/ left hand
Hold ET tube in right hand
Press blade against pulled out tongue,
exposing trachea
Can be used to hold epiglottis down
◦ Lightly!

Blade too far forward will obstruct view
Page
18


Stylet runs inside the ET tube
Made of strong wire/metal
◦ Stiffens the tube and molds the tube

Sticks out past the ET tube
◦ Provides smaller, blunt point to first pass through
the vocal cords
◦ Allows larger ET tube to slide into trachea

Stylet should be longer than ET tube!
◦ Why?
19
2. Blind








Used in dogs and horses
NOT suitable for cats, very small dogs, or patients
with edema, swelling or trauma
Lateral recumbency (RIGHT lateral in dogs)
Head and neck extended and mouth open
Advance tube with bevel parallel to vocal cords
Move soft palate up and out of the way and
epiglottis down
Advance upon expiration
Rotating tube to follow curve and point tip down
3. Tactile
Cattle, large exotics, a few large dogs
 Finger holds down the epiglottis
 Slide tube into trachea using your
finger as a guide





More difficult
Small mouth and sensitive larynx
Dome shaped vocal cords tend to close and
push tube to side
Swallowing reflex or contact with end of
tube causes laryngospasm

Laryngeal sensitivity
◦ Can be reduced by application of topical
anesthetic
Apply 0.1 cc of 2% Lidocaine soln. on glottis
(without the needle!)
◦ Or use cotton swab

Can also coat the end of the tube w/
lidocaine gel





Sternal recumbency
Good light source
Use direct visualization technique-must be
able to see vocal cord opening before
inserting tube
Stylet is helpful!
Cats often cough – don’t let go!


Condensation seen in ET tube
Feel air through tube
◦ Place something light or metal
at end of ET tube

Palpate throat
◦ One tube – you’re in
◦ Two tubes – you’re in esophagus

Normal breathing sounds
◦ No gurgling

Patient can not vocalize
Using Machines

Give a breath = chest should rise
(stomach should NOT)
◦ Listen to BOTH lung sounds



Rebreathing bag and flutter valve should
move with respirations
Capnograph should give appropriate reading
Radiographs
Page
32
Roll gauze
 Rubber Band
 IV line
Paper tape-birds/reptiles





Tie around tube first, then around patient
Do not include small tube used for cuff inflation
ALWAYS use a bow tie, not a knot
A L W A Y S disconnect the patient from the anesthetic
tubes when moving OR repositioning
Page
34


Cats: 1 – 2 cc of air
Dogs: 2 – 10 cc of air
◦ Valve port should inflate, but not be
maximally full of air
◦ If more than 10 cc needed:
 Leak or need a larger ET
tube


Recheck every 30 min of surgery – especially
after moving or repositioning patient
If you are running anesthesia for longer than 2
hours reposition the tube slightly so pressure
necrosis does not happen.
◦ Must deflate cuff before moving tube!
Your patient will be in recovery
◦ Sternal or lateral recumbency
◦ Head and neck extended
Deflate the cuff when the patient shows signs of
waking up
 Remove ET tube after un-stimulated swallowing has
returned
 Prevent obstruction of airway with tongue by pulling
tongue forward during and after pulling the tube
*Waiting too long can cause patient to bite tube in half*


Brachycephalic animals – should be head up,
chewing on tube before it is pulled



Patients may cough for 1 – 2 days post
operatively
Should not be severe or continue to get worse
Advising owner will avoid phone calls and
later explanations!



Inflate cuff and leave inflated until dry
Wash inside AND outside of endotracheal tube
Use warm soapy water to get mucus off
◦ Commercial brushes available, cotton swabs, pipe
cleaners





Rinse
Disinfect for minimum of 15 minutes in Ultra
Sonic Cleaning soln. with DILUTE chlorhexidine
Rinse VERY well
Hang upright to dry over night
Deflate cuff