Extrathoracic Airway Disease Flashcards
what is the extrathoracic airway?
portion of trachea outside of thoracic cavity
upper airway: rostral to cricothyroid membrane
when the radius of the trachea decreases by half, how much does the resistance increase?
by a factor of 16
what are upper airway inspiratory abnormalities?
inspiratory obstruction
inspiratory dyspnea
inspiratory stridor
what is a grade 1 obstruction?
slight: normal ventilation can be sustained indefinitely
what is a grade 2 obstruction?
mild: most patients develop mild hypoxemia and hypercapnea rather than increasing the work of breathing
what is a grade 3 obstruction?
severe: patient is unable to maintain alveolar ventilation
increase in PaCO2 and decrease in PaO2
what is a grade 4 obstruction?
patient will die without immediate relief
what are the physiological responses to extra-thoracic obstruction?
reduce work of breathing
lower tidal volume
higher respiratory rate
accept hypoxemia/hypercapnea
what are some functional abnormalities of the upper airway?
sinusitis
nasal aspergillosis
feline upper respiratory disease complex
calicivirus
what is reverse sneezing?
aspiration of contents of nasopharynx to oropharynx
contraction of inspiratory muscles with adduction of laryngeal cartilage
sudden opening of glottis produces rapid inhalation
where is atrophic rhinitis most likely to show up?
young herds with many gilts
large permanently populated farrowing houses
poor environmental conditions
what are the clinical signs of atrophic rhinitis?
unilateral nasal bleeding
deviation of face
growth retardation
tear staining
what are the clinical signs of Pasteurella multocida in a rabbit?
sneezing
coughing
nasal discharge
open mouth breathing
what makes up brachycephalic airway syndrome?
stenotic nares
overly long soft palate
redundant pharyngeal mucosa
what are some secondary changes to brachycephalic syndrome?
everted laryngeal saccules
laryngeal collapse
what are the clinical signs of canine laryngeal paralysis?
change in bark
exercise intolerance
collapse
larger dogs
older dogs
what causes canine laryngeal paralysis?
<25% congenital
neurologic disease
damage to laryngeal cartilages themselves
degeneration of nucleus ambiguous
myasthenia gravis
polymyosities of the abductor muscle
what is the upper airway defined as?
everything rostral to cricothyroid membrane
what are the rigid portions of the upper respiratory tract?
nasal cavity
trachea
what are the collapsible portions of the upper respiratory tract?
external nares
nasopharynx
larynx
what purpose does the nasal cavity serve?
large surface area for heat and water exchange
what animal is an obligate nose-breather?
horse
what does the lateral compartment of the guttural pouch contact?
maxillary and carotid arteries
what is included in the larynx?
arytenoid cartilages
aryepiglottic folds
glottis
epiglottis
what signs are associated with dental disease inoculating the maxillary sinus in horses?
fetid nasal discharge
difficulties eating
swelling over maxillary sinus
what can predispose horses to epiglottic entrapment?
abnormally short epiglottis
upper airway inflammation
is dorsal displacement of the soft palate a dynamic or fixed collapse of the upper airway?
dynamic
how many does equine laryngeal paralysis affect?
8% of thoroughbred racehorses
50% of horses that stand higher than 17 hands
what muscle is of greatest interest in equine laryngeal paralysis?
cricoarytenoideus dorsalis
what does the axonopathy of the left recurrent laryngeal nerve result in in equine laryngeal paralysis?
atrophy of the intrinsic laryngeal muscles
