The Trachea Flashcards
Number of trachea layers?
What are they?
4: mucosa, submucosa, cartilaginous-muscle layer and adventitia
What is the thickest structure in the trachea, how doe sit run?
Hyaline cartilage is thickest ventrally and then tapers along the curved arms.
What happens to Hyaline cartilage with age?
Calcifies
What is different in the dorsal trachea?
Dorsally there is no cartilage, instead there is a dorsal tracheal ligament
Wat 3 things is the dorsal tracheal ligament composed of?
mucosa, connective tissue, and smooth muscle
What breeds are predisposed to hypoplastic trachea? (2)
French bulldog
english bulldog
What is seen anatomically with a hypoplastic trachea?
Rings are overlapping with minimal tracheal membrane.
Trachea:
A) What is it lined by?
B) How dos it lubricate? (2)
A) pseudostratified ciliated columnar epithelium
B) lubricated by goblet cells and lubricating glands
The cilia sweep bronchial mucus towards the larynx at a rate of ?
12 mm per minute.
What allows contraction and expansion of the diameter?
Pleated mucosa
What sized tube for tracheostomy in dogs?
Size 5 and 6 tubes
What sized tube for tracheostomy in cats?
3 or 4
Emergency tracheostomy:
How to?
Cut down onto the needle or go straight down with an 11 blade - stay ventral. Split the rings to access the trachea.
The incision can also be made vertically through the rings but the risk of stenosis is greatly increased.
Emergency tracheostomy; What can be used to locate the trachea if it is swollen?
Needle
Cuffed tracheostomy is only used when?
ventilation is required
Stylets or cannulas decrease the lumen of the tracheostomy tube, thus what effect on airway resistance
increasing
What causes stenosis during tracheostomy?
Transecting rings (not splitting)
The presence of the tracheostomy tube results in what damage? (3)
loss of cilia,
inflammation,
mucosal erosion
Effect of tracheostomy on arytenoid abduction.
Reduces
What surgery is tracheostomy useful in? When do you place?
intraoral surgery
- Ideally placed as an elective surgery after oral intubation.
When to remove tracheostomy? (2)
- obstruction gone
- the animal can manage with occlusion or removal of tube
What tracheostomy tube is used?
simple silicon tubes are used, with no inner cannulas or cuffs (unless ventilating). Shiley™ tubes work well.
First removing the trach tube; what to do?
Obseverve patient
When do trach tubes commonly need replacing?
night if the obstruction is nasopharyngeal or nasal and titrate the use of the tube down over a couple of days.
How to heal tracheostomy?
2ry intention
Benefits of 2ry intention healing for trach tubes? (2)
additional airflow for a few days
prevent subcutaneous emphysema.
What proportion of the tracheal lumen should be occupied by the tracheostomy tube?
50-60%
Why is the trach tube smaller than trachea diameter? (2)
- breathing around the tube if it occludes
- reduce damage to the laryngeal mucosa.
Tracheostomy tubes: How to position
- Extend the head over a sandbag.
Tracheostomy tubes:
Where is the incision?
Which muscles do we go through? (2)
- ventral midline incision over trachea from caudal larynx to 7th or 8th tracheal ring and continue through subcutaneous tissues
platysma and sphincter coli muscles.
Tracheostomy tubes:
Separate the two ? muscles along the midline to expose ventral trachea.
sternohyoid
Tracheostomy tubes:
In thick neck dogs such as bulldogs, consider bluntly dissecting dorsal to the trachea and placing what through the strap muscles to bring them into apposition dorsal to the trachea. This suture pushes the trachea superficially closer to the skin, enabling tube changes.
a mattress suture
Tracheostomy tubes:
Where is the trachea incised? How large is incision?
Make circumferential tracheal incision ventrally between cartilage rings 3 and 4 or 5 and 6. Incision should be around 50% of the tracheal circumference
Tracheostomy tubes:
Care to avoid what? Where are they?
taking care to avoid recurrent laryngeal nerves dorsolaterally.
Tracheostomy tubes:
A) Where are stay sutures place?
B) Using what?
C) How long are they there for?
A) around the cartilage ring above and below the tracheal incision
B) Place 2 or 3 metric monofilament, non-absorbable (e.g. polypropylene) stay sutures
C) Duration of management, used to open stoma during replacement. UNTiL REMOVED
Labels should be placed on trach tube stay sutures; saying what?
Head and tail end!
After trachea incision, how is the trach tube placed?
Withdraw the ET tube so the tip is just cranial to the tracheostomy incision and insert the tracheostomy tube through the tracheal stoma and into the trachea below the ET tube. Switch anaesthetic circuit to the trach tube and remove ET tube from mouth.
Place a what between the tracheostomy tube and the subcutaneous tissue/trachea
sterile swab
How to tie trach tube in?
Use nylon tape to tie the tube in place around patient’s neck.
How to care for a trach tube? (3)
Intensive care – the patient needs continuous monitoring
Use a humidifier/nebulisation (steam) for 10-15 minutes every 3-4 hours
Remove and clean every 8-24 hours depending on discharge being produced.
ABx with trach tube?
Within 24 hours the tube will be colonized with oropharyngeal flora. Avoid antibiotics whilst the tube is in unless indicated for i.e., aspiration pneumonia.
Indications for a Permanent Tracheostomy? (3)
laryngeal collapse,
permanent upper airway obstruction
damage to proximal trachea.