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.

INTERVENTION

Provide interventions and supportive care to alleviate any potential confounding factors:

• Fear and anxiety: tranquilize, sedate, or anesthetize if necessary. (See K9 Analgesia and Anesthesia.)
• Hyperthermia: active and/or passive cooling to maintain appropriate body temperature. (See K9 Heat Injury CPG.)

Provide oxygen supplementation while preparing to access and extract the obstruction. Consider that most UAOs are not complete obstructions. Most often, some air can still flow around the obstruction and reach the lungs.

Ensure personnel safety to avoid bite injuries. Do not stick one’s hand into the mouth of a conscious MWD.

Quickly and safely establish a patent airway by removing any obstructive material from the upper airway.

• Suction or wipe the mouth and oropharyngeal area of any excessive secretions or blood that may be contributing to the UAO and to allow for greater visualization. BE CAREFUL to not push the object deeper into the airway.
• Consider providing abdominal thrust maneuver in MWDs with a moveable object located within or rostral to the supraglottic area. Only attempt if the object is known to be lodged in the trachea or larynx and is confirmed to be smooth. DO NOT attempt in MWDs with sharp object obstructions or with known or suspected abdominal trauma.

Abdominal  Thrust  Technique

• Approach the MWD from the rear.
• Reach over top and bear hug the MWD by placing your fist(s) immediately caudal to their xiphoid process.
• Compress the abdomen with five quick upward (craniodorsal) thrusts. When performing the abdominal thrusts, slightly elevate the hind end, while ensuring the MWD’s front feet remain on the ground. Avoid picking up and holding the MWD completely off the ground or holding them upright like a person.
• Check to see if the object was dislodged.
• Repeat 1-2 times. If unsuccessful, immediately move to an alternate airway clearance technique.

Non-Invasive  Extraction  Technique

An alternative to performing abdominal thrusts, with the mouth held open, use large forceps (e.g., Magill) or similar instrument to extract any movable objects or obstructions.

Attempt extraction only under direct visualization of the obstructive material. AVOID performing a blind 2-finger sweep of the oral cavity if the object is not readily visible. This can push the object further down into the airway.

External  Extraction  Technique

Ball-like objects that are causing an UAO can be removed by placing the dog on their back with their head and airway parallel to the floor. Feeling the ball lodged in the throat, place thumbs on each side of the trachea below the ball (toward the body), using the middle fingers to help open the jaw. Push down and out against the ball, ejecting it from the mouth.

If attempts to clear or remove object or obstruction from the airway using the above non-invasive techniques have failed and/or the MWD collapses, immediately proceed to performing a surgical airway (CCT/TT).

Continue to provide oxygen supplementation and/or assisted ventilations, while preparing to perform the surgical airway.

• Partial UAO: Provide artificial ventilation via BVM technique or mouth to snout.
• Complete UAO: Consider needle CCT or tracheal oxygen insufflation to provide oxygen delivery (see Table 1).