The structures of the upper airway consist of the nasal passageways, nasopharynx, oropharynx, larynx, and extra-thoracic trachea (cranial to the thoracic inlet). An MWD with a UAO breathing pattern typically displays respiratory distress characterized by a labored inspiratory effort with a normal or passive expiratory effort and abnormal, audible upper airway noise such a stridor or stertor (see Figure 1).

CAUSES

Common causes of UAO common to MWDs include:

• Oromaxillofacial trauma (jaw fractures).⁵
• Tracheal compression due to trauma-induced hemorrhage and muscle edema in the cervical area.
• Direct tracheal injury caused by penetrating cervical trauma from stab wounds, gunshot wounds, bite wounds, or secondary blast injuries (blast-energized fragments, shrapnel, explosive debris components, and environmental debris).
• Mechanical obstructions, intraluminal (foreign objects, blood clots).
• Dynamic or functional obstructions (laryngeal paralysis).
• Tracheal swelling and edema from miscellaneous non-trauma causes (smoke inhalation, anaphylaxis).

DIAGNOSIS

Primarily based on the history of trauma, mechanism of injury, and presenting signs to include the primary anatomical areas of injury (head and cervical region).

Observe the MWD for clinical signs of an UAO. If the MWD is unconscious, observe closely for signs of spontaneous breathing and listen for any obvious audible abnormal airway noises (stridor, stertor). Consider that any MWD that can bark, growl or whine most likely has a patent airway.

Common signs of UAO:

• Pawing at mouth
• Gagging, excessive drooling
• Frequent swallowing motions
• Audible, abnormal airway noises (stridor, stertor)
• Extended head and neck
• Elbows and upper legs held out from the chest (e.g., “tripod position”)
• Reluctance to lie down

Palpate and examine the face, muzzle, nose, mouth, external laryngeal area, and trachea for deformities, traumatic wounds, or other abnormalities.

Safely assess the airway for patency by opening the mouth and directly examining the oropharyngeal cavity.

IF UNCONSCIOUS:

• Place the MWD in the recovery position (sternal recumbency or prone position). Tilt the head slightly back and extend the neck.
• Physically open the mouth and pull the tongue forward to help open the airway and allow optimal visualization of the mouth and oropharyngeal cavities.

Note: When present, have the handler securely hold the MWD’s mouth in an open position. This allows medical personnel the ability to visualize and assess the entirety of the mouth and oropharyngeal cavities thoroughly and safely. If no additional people are available, use a roll of gauze, rope, or leash looped behind the upper and lower canine teeth to pry and securely hold the MWD’s mouth open. Consider using a roll of medical tape or syringe tube casing without a plunger (Figure 4) as a mouth gag to keep the mouth open.