SACCM 19: Tracheal Collapse

Question 1

What is the suspected etiology leading to tracheal collapse?

Answer 1

decreased glycosaminoglycan, chondroitin, and Ca contents leading to dorsal trachealis flaccidity and loss of rigidity of cartilages

Question 2

Why are dogs with tracheal collapse predisposed to airway infection?

Answer 2

chronic irritation and inflammation impairs mucociliary escalator

Question 3

What are the grades of tracheal collapse?

Answer 3

Grades I to IV
each grade with 25% reduction in diameter
grade IV –> W-shaped inversion of the ventral cartilages

Question 4

which grades from I-IV are static versus dynamic in tracheal collapse?

Answer 4

grade IV: static airway obstruction
ventral W-shaped inversion of cartilages

Question 5

What are the 2 proposed clinical phenotypes of tracheal collapse?

Answer 5

• obstructive honkers
• nobobstructive coughers

Question 6

compared to fluoroscopy how commonly do radiographs misdiagnosed location or presence of tracheal collapse

Answer 6

• Radiographs misdiagnosed location of tracheal collapse in 44% of dogs, failed to diagnose tracheal collapse in 8% of dogs compared to fluoroscopy

Question 7

in-light of radiographs being a poor diagnostic modality for identifying and localizing tracheal collapse, why should you still take them?

Answer 7

to assess for other pathologies (bronchiectasia, heart disease, …)
and trahceal malformation

Question 8

on what aspect of the trachea will tracheal malformation from tracheal collaspe be present?

Answer 8

ventral margin

Question 9

how common is laryngeal dysfunction in dogs with tracheal collapse?

Answer 9

30% of dogs with tracheal collapse will have laryngeal dysfunction

Question 10

how effective is medical management in tracheal collapse

Answer 10

• 71% of dogs can be effectively managed with medications for more than 12 months

Question 11

What are the parts of medical management for tracheal collapse?

Answer 11

• Anxiolytics, O2 supplementation, cough suppressants, tapering anti-inflammatory doses of steroids  for crisis management
• Bronchodilators controversial  may be beneficial in bronchial collapse, chronic bronchitis, especially in coughing phenotype
• Use of harness (over collar), weight loss, control of exacerbating factors (heat, stress, excitement)

Question 12

what are the possible complications of tracheal rings

Answer 12

• 10-21% laryngeal paralysis, other complications: infection, tracheal necrosis, progressive tracheal collapse

Question 13

In what phenotype of tracheal collapse should tracheal stenting not be used?

Answer 13

unlikely to benefit coughing phenotype

Question 14

You have assessed the maximum tracheal diameter using PPV breath holds at 20 cm H2O. How do you use this measurement to determine stent diameter?

Answer 14

stent should be 10-20% larger than maximal tracheal diameter

Question 15

how long should a tracheal stent be?

Answer 15

should be entire length of trachea 1cm caudal from cricoid cartilage and 1 cm cranial to carina

Question 16

describe the post tracheal stent management

Answer 16

• Most discharged next day
• Antibiotics pending airway culture results
• 2-3 week tapering course of steroids
• Q6-8h cough suppressant  however will still cough for 6-8 weeks post stent placement
• Thoracic radiographs every 3-4 months for first year than every 6 months

Question 17

List 3 tracheal stent complications

Answer 17

• tracheal stent migration
• tracheal stent fracture
• inflammation tissue formation (granulation) -> from poor mucosal ingrowth