Airway Obstruction Flashcards
What sound might you hear with nasal obstruction
stertor
as you get lower down the airway, obstructions tend to sound more
more high pitch (stridor)
What are two causes of functional airway obstruction
1) Laryngeal paralysis, collapse
2) Tracheal malacia
What might cause a mechanical airway obstruction
1) Intraluminal
-Edema
-Masses, infl or neoplasia
-Trauma
-anatomy
-objects
2) Extraluminal
-Masses (LN, abscess, hematoma)
-Trauma, Crushing
What is the challenge with noticing respiratory disease in brachycephalics
they are considered “normal”
might have a subtle progression, an exhausted physiologic respiratory reserve, and vicious cycle
What is the viscous cycle of airway obstructions
1) Airway obstructions
2) Increased work
3) Turubulent flow
4) Edema leading to more airway obstruction
What factors from airway obstruction lead to a greater work, which means turbulent airflow and edema
-Anxiety
-Panic
-Hypoxemia
-Hypercapnia
-Dyspnea
-Hyperthermia
For dogs with airway obstruction you should do cooling until
exogenous cooling to 103F
best to shave, get skin wet and blow fan onto the dog
can also use urinary catheter and inject saline, allow it to get some heat and then drain it out
What does blowing cold air on the face do
cool air directed at the face decreases air hunger
-Stimulation of cold receptors in upper airway
-Trigeminal nerve
via diving reflex
The diving reflex is stimulated by what nerve
Trigeminal nerve
What is the diving reflex
present in all mammals
cold air < cold water
tolerance of hypoxemia and hypercapnia
decreased ventilatory drive -> apnea
Bradycardia and vasoconstriction
What are the effects of the diving reflex
1) Decreased ventilatory drive -> apnea
2) Bradycardia
3) Vasoconstriction
*allows tolerance of hypoxemia and hypercapnia
You should do exogenous cool to
103F
What is the best way to cool a dog in the field
dump in a pool of cold water
What sedation drugs would you like to use for a pug in a respiratory crisis
Butorphanol
Acepromazine
What is nebulized epinephrine
ephinephrine - targets alpha receptors to vasoconstrict the upper airway mucosa
nebulized into the airway
Mitigates airway edema
When can nebulized epinephrine be used
1) Acute airway obstruction
2) Post extubation recovery
*might also help after smoke inhalation
this functions to mitigate airway edema - via alpha receptor vasoconstriction of upper airway mucosa
What is the nebulized epinephrine dose
Epi dose 0.05 mg/kg
-Dilute in 5ml 0.9% NaCl
-Deliver for 10 minutes
What can you give for acute airway obstructions and after extubation recovery to mitigate airway edema
Nebulized epinephrine
Epi dose 0.05 mg/kg
-Dilute in 5ml 0.9% NaCl
-Deliver for 10 minutes
What are the adverse effects of nebulized epinephrine
-Excitement *
-Nausea *
-Grey mucous membrane (ugly)
-Tremors
-Tachycardia
-Arrhythmias
What corticosteroids can you give to stabilize patients with acute airway obstruction
Dexamethasone SP 0.15 mg/kg IV
up to 4-6 hours for effect on swelling
this helps on inflammation
What are the characteristics of brachycephalic obstructive airway syndrome (BOAS) *
1) Stenotic nares, aberrant turbinates
2) Big dense tongue
3) Elongated soft palate, thick
4) Hypoplastic trachea
What are the issues with a BOAS dog with stenotic nares
cant abduct alar folds
+/- obligate mouth breathing
BOAS dogs have aberrant turbinates, what does this mean
denser turbinates, covered in more mucosa
-failed heat dissipation
-nasopharyngeal extension
T/F: BOAS dogs have bigger and denser tongue
True- and its not tapered
What is the consequence of a BOAS dog having a larger tongue
less place to regurgitate
BOAS dogs have a long, thick soft palate that extends past
epiglottis
the fatter the dog…. the fatter the….
soft palate
in BOAS dogs, what is the consequence of hypoplastic trachea
rings are rigid and free ends appose with a short dorsal tracheal membrane
if the animal has a ocmplete airway obstruction and there is no time for sedation, what do you do
Cricothyroidotomy
When intubating in resp crisis, what should you observe in your airway exam
-soft palate: is it thick and edematous
-are the arythenoids moving
When trying to intubate a BOAS dog, you see that the soft palate is in the way and the arythenoids are really edematous. What do you do
1) Decrease edema: cool patient, consider systemic steroids, dextrose compress
2) Palatopexy
3) Manage lung disease
Procedure where the soft palate is attached to the hard palate to manage brachycephalic obstructive airway syndrome dogs
palatopexy
you should screen dogs with airway obstruction for
non-cardiogenic pulmonary edema
due to negative intrathoracic pressures
may cause dog to be intubated longer times
Why are dogs with airway obstruction at risk for non-cardiogenic pulmonary edema
due to the negative airway pressure from the airway obstruction and turbulence, there is a lower inspiratory flow and smaller tidal volume
this leads to negative intrathoracic pressure
Due to increased resistance from airway obstruction, what are some consequences of increased resistance
-Airway: recurrent laryngeal collpase, everted laryngeal saccules
-Lung: non-cardiogenic pulmonary edema
-GI: regurgitation, vomiting, hiatal hernia, aspiration pneumona
-Heat tolerance
How might dogs with airway obstruction get GI issues
1) Airway resistances leads to
2) negativ intrathoracic pressure
3) Barotrauma
4) Regurgitation, vomiting hiatal hernia
5) Aspiration pneumonia
all this makes it worse because of increased work of breathing leading to airway edema
From negative intrathoracic pressure, what GI issues might occur
Regurgitation
vomiting
hiatal hernia
leading to aspiration pneumonia
What issues in the airway might occur due to negative intrathoracic pressure
-Recurrent laryngeal collapse
-everted laryngeal saccules
What can you do as immediate stabilization for dogs with an airway obstruction
Sedation
O2
cooling
Neb. Epi
Intubation
What can you do as a short term treatment for dogs with an airway obstruction
-Steroids (short course)
-Cool and calm
-Palatopexy
-Temp Trach
What can you do as a long term treatment for dogs with airway obstruction
BOAS surgery
Weight loss
