a. Conscious MWD with no airway problems identified:
- No airway interventions needed.
b. Unconscious casualty without airway obstruction:
- Place unconscious MWD in a recovery position (sternal recumbency/ prone if possible or allow MWD to remain in lateral recumbency).
- Perform basic airway maneuvers:
- Extend the head and neck into a straight in-line position;
- Grasp the tongue, gently extend out of the mouth, and pull it down over the lower jaw.
- Consider endotracheal intubation to achieve / maintain patent airway.
- Consider using a mouth gag to keep the MWD’s mouth open and prevent trauma to endotracheal tube. Examples of a field expedient mouth gag may include:
- 1 – 2 inch roll of medical tape;
- 2 inch wide roll of self-adherent bandage (Coban®/Vetrap®); or
- Cutting the end off of a 3 – 5 mL syringe tube casing and securing over the upper and lower canine teeth.
- Placing a portion of a kong between MWDs teeth to open the mouth
c. Conscious MWD with airway obstruction or impending airway obstruction:
- Clinical Signs:
- Pawing at mouth, gagging,
- Excessive drooling,
- Frequent swallowing motions,
- Extended head and neck,
- Elbows and upper legs held out from the chest (e.g. “tripod position”),
- Reluctant to lie down,
- Noisy breathing (stertor or stridor),
- Cyanosis (bluish gums); late sign.
- Allow the MWD to assume the ‘position of comfort’ or the position that best allows the MWD to breath with minimal restriction of air flow and that protects the airway, to include sitting or standing.
- Palpate throat (pharyngeal area, larynx, and trachea to identify any abnormal mass or foreign material.
- Open mouth to examine oropharyngeal area:
- Avoid placing hands or fingers directly in MWD’s mouth.
- Consider using a leash, rope or roll gauze looped behind the upper and lower canine teeth in attempts to pry and hold the MWD’s mouth open.
- Consider sedating the MWD (see section 10 below).
- Use suction if available, appropriate and feasible based upon MWD disposition/mental status.
d. If attempts to clear or remove the airway obstruction have failed or the MWD collapses or becomes unconscious consider one of the following techniques:
- Orotracheal Intubation (OTI) / Endotracheal Intubation (ETI):
- Preferred first-line technique for gaining airway access in MWDs and with training this can be accomplished in field conditions.
- Use of a laryngoscope, although helpful, is not often required for MWD ETI; if available, a #4 - #5 Miller (straight) blade is recommended for MWD >25 kg (55 lbs).
- Use a 8.0 – 10.0 mm internal diameter ET tube (ETT) for MWD weighing > 25 kg (55 lb).
NOTE: intubation of the MWD is most easily performed with the dog in sternal or prone position (but can be performed in lateral), head and neck extended, and tongue pulled forward. Capnometer reading >10 mmHg also verifies correct placement.
If necessary assisted ventilation via an Ambu-bag can be performed at a rate of 8-10 breaths per minute.
- Surgical Airways
- Surgical Cricothyrotomy (CTT)
- 1) Use techniques recommended for humans.
- Bougie-aided open surgical, flanged and cuffed airway cannula, 6 – 9 mm internal diameter, 5 – 8 cm intratracheal length.
- Standard open surgical, flanged and cuffed airway cannula, 6 – 9 mm internal diameter, 5 – 8 cm intratracheal length.
- Surgical Tube Tracheostomy (TT)
- 1) Use the largest internal diameter tube that fits into MWD trachea; aim for a TT that is at least 70% of the estimated internal tracheal lumen diameter.
- 2) Select a TT length of 5- 8 cm or one that does not extend beyond the thoracic inlet/point of shoulder.
* Blind Insertion Airway Device / Nasopharyngeal airways / Extraglottic Airway Devices have not been evaluated in canines and should not be utilized in MWDs.
e. Cervical Spinal stabilization is not necessary for MWDs suffering only penetrating trauma.
f. Monitor hemoglobin saturation (SpO2) and capnography when available, to help assess airway patency
- Normal SpO2 values in MWDs are similar to those in people (> 94% on room / atmospheric air). Pulse Oximetry probe placement for MWDs in order of preference: tongue, non-pigmented area of lip, ear pinna, prepuce (male) or vulva (female); Recent data demonstrated the use of a human-designed neonatal pulse oximetry adhesive sensor attached to the base of a canine’s tail, may provide an alternative site for accurate and feasible pulse oximetry measurement in canines NOTE: Accurate pulse oximetry measurement is often only achievable in an unconscious or adequately sedated/anesthetized MWD.
- Capnography for MWDs is the same as for humans. An ETCO2 monitor can be attached to an intubated MWD. ETCO2 levels should be the same as for humans (35-45 mmHg).
g. Always remember that the MWD’s airway status may change over time and requires frequent reassessment.
Notes:
- Similar to a human casualty that can speak clearly without any respiratory distress, consider a MWD that is barking, growling, or whining without any clinical signs of respiratory distress has a patent airway.
- Consider monitoring the MWDs rectal temperature. Canines rely on panting to dissipate body heat, therefore, any upper airway obstruction increases their risk for a potential a heat-related illness.
- Due to anatomical / conformational differences, the tongue is not a major source of upper airway obstructions in canines as it is in human casualties.
- In MWDs experiencing respiratory fatigue from prolonged or strenuous increased work of breathing, even mild sedation may increase the risk of imminent respiratory failure/arrest; therefore, have resources prepared to perform rapid ETI or CTT/TT before administering any sedative or analgesia.
- ETI is considered the first-line option for advanced airway management in an unconscious or anesthetized MWDs. Canines possess a proportionally larger tracheal lumen diameter as compared to people. In order to achieve an airtight seal, it is recommended to select an ETT that is 70% of the canine’s internal tracheal lumen diameter. Digital palpation of the trachea in the cervical neck region is the most reliable method for estimating the canine’s tracheal diameter. In most MWDs a size 8.0-10.0 endotracheal tube is appropriate. To avoid the risk of one-lung intubation, determine the appropriate ET/CTT/TT length by measuring from the front or the canine incisors to the thoracic inlet or point of shoulder.
- Surgical airways are not warranted in an unconscious or anesthetized MWD that has no direct upper airway trauma unless the performance of basic airway positioning maneuvers is unsuccessful in opening the airway and / or the provider is unable to successfully perform ETI.