From general practice to emergency medicine, brachycephalic patients can be challenging. Their unique anatomy makes them more vulnerable to certain conditions – like respiratory issues, cardiac illnesses and heat stress – and common procedures can, in some cases, lead to complications.
This overview discussion will offer a brief description of:
- common anatomic abnormalities seen in brachycephalic animals.
- general handling techniques to decrease risks associated with commonly performed procedures in a veterinary setting (venipuncture, blood pressure measurement, etc.).
- common emergency presentations and basic guidelines for management.
Brachycephalia (or brachycephaly) is defined as a congenital malformation of the skull in which premature closure of the coronal suture results in excessive lateral growth of the head, giving it a short, broad appearance. Dog breeds that fit the brachycephalic criteria most commonly include bulldogs (French, English, American, etc.), pugs, shih tzus, Boston terriers and boxers. Cat breeds that fit the brachycephalic criteria most commonly include Himalayans, Persians, British and Scottish shorthairs and Burmese. Other breeds of dogs and cats can also be affected.
Brachycephalic anatomic abnormalities include shortened nasal passages, protruding eyes, often narrowed nares, tongues that do not fit within the oral cavity, and elongated soft palate. (Elongated soft palate and narrowed nares characterize brachycephalic airway syndrome or BAS). Secondary abnormalities often include everted laryngeal saccules and everted tonsils, and ultimately laryngeal collapse can develop. Many patients who have the primary anatomic abnormalities also exhibit a hypoplastic/stenotic trachea. In many cases, surgical correction of the upper airway anatomic abnormalities offers the best management of this condition; however, it does not return these patients to normal function.
GENERAL HANDLING TIPS
Stress, anxiety, air hunger and difficulty regulating body temperature can create a perfect storm for acute respiratory distress and even respiratory arrest in brachycephalic patients. These factors can be mitigated with several easy and cost effective management strategies in any veterinary environment.
Patients with brachycephalic conformation or BAS often panic when conventional restraint techniques are employed. This is especially true with neck hold positions due to further narrowing of their available airflow space in the oropharynx. Dorsal and lateral forced restraint positions can also exacerbate air hunger and lead to panic. These techniques can start a cycle of air hunger and panic that, in some cases, can progress to life-threatening respiratory distress.
However, brachycephalic breeds will tolerate many procedures if they are allowed to remain standing or are held in an upright position. An effective alternative for traditional restraint techniques can be found in the “pug hold” (Figure 1). This technique is ideal for small, easily lifted brachycephalic patients. The patient is lifted with the near side against the restrainer. The restrainer’s nondominant hand is placed over the trunk, under the thorax and grasps the near foreleg just above the elbow. The dominant hand can then gently cradle the far side of the face and head without putting any pressure on the laryngeal region. With this technique, the patient is safely restrained without the ability to jump or effectively bite. This hold offers easy access to the far side hind and forelimbs for venipuncture and/or IVC placement.
Figure 1. The “pug hold” is an effective alternative for traditional restraint on brachycephalic patients.
In patients who are actively attempting to bite despite careful handling, placement of a large cone collar can provide effective barrier protection for staff without exacerbating respiratory signs (Figure 2). Basket head hoods can also be considered, though they can make access to the face difficult. Due to the risk of airway compromise, it’s best to avoid use of soft or hard traditional muzzles or cat masks.
Figure 2. Using a cone collar, instead of a muzzle, can provide effective barrier protection for staff without exacerbating respiratory signs in the patient.
With attention to careful dosing, light sedation and anxiolytics can be effectively employed when treating brachycephalic patients. Butorphanol is often used in our practice for patients who exhibit anxiety with severe panting and distress.
Oxygen support is easy, inexpensive and can be very useful for brachycephalic patients, even without obvious signs of respiratory distress. O2 support is routinely provided at DoveLewis during emesis induction and often during venipuncture, blood pressure measurement, etc.
Heat stress is common, especially in patients who are anxious and panting excessively. Excessive panting can lead to laryngeal tissue swelling, further worsening respiratory difficulty. External cooling should be provided for any panting brachycephalic patient, even if their core body temperature is normal. This holds especially true if the rectal temperature is above 102 degrees.
COMMON EMERGENCY PRESENTATIONS
During all emergency presentations for brachycephalic breeds, it is important to keep respiratory status in mind. Common emergency presentations often require additional respiratory support, even if the respiratory system is not directly involved.
Typical allergic reactions often present with facial swelling, hives, pruritus and, in some cases, vomiting and anaphylaxis. General treatment is unchanged in brachycephalic species, but special attention should be given to respiratory status and stabilization. The use of short-acting steroid therapy is often indicated to reduce laryngeal swelling along with hypersensitivity signs. Oxygen support is always recommended, and intubation for respiratory stabilization should be considered if the patient is exhibiting respiratory distress.
Respiratory distress (cardiac, pulmonary, obstructive)
Patients who present in respiratory distress should be provided immediate oxygen support during evaluation. Stabilizing the patient’s respiratory status prior to diagnostics is crucial (especially prior to taking thoracic radiographs). This could include light sedation (butorphanol is often a good choice), and, if indicated, the administration of diuretics (cardiac disease, CHF) or short-acting steroid therapy (obstructive, collapsing trachea, etc.).
A thoracic ultrasound can be employed without the need for restraint. A thoracic ultrasound can sometimes help determine between pulmonary edema, pleural effusion and, in some cases, pneumothorax. In cases of a brachycephalic obstructive airway crisis, steroid therapy is often employed (if not contraindicated) and direct airway support may be required (intubation and ventilation, temporary or permanent tracheostomy).
Vomiting (and risk of aspiration pneumonia)
Brachycephalic patients with vomiting are at increased risk for pneumonia, secondary sinusitis/rhinitis and persistent regurgitation secondary to esophagitis. Vomiting brachycephalic patients should be given anti-nausea medication as soon as possible on presentation to control vomiting and decrease the risk of these secondary complications. Further work up should be performed as usual for patients with vomiting. The addition of thoracic radiographs should be considered for aspiration pneumonia screening even if there is no evidence of immediate respiratory distress. Preemptive use of anti-nausea medications should be considered in patients undergoing sedation or anesthesia.
Proptosed globe is a common presentation for brachycephalic patients and can be seen with or without inciting trauma. Pain management should be initiated on presentation and artificial tear gel/ointment should be applied to the affected eye on presentation to help support tissue viability. Replacement of the globe and temporary tarsorrhaphy is often successful if the pupillary light reflexes (PLRs) are intact, if menace and motor function are present, and if the globe is not visibly ruptured. However, it can be difficult due to the shallow orbit in brachycephalic patients. Enucleation of the affected globe is also a reasonable treatment option, especially if there is a poor prognosis for return of vision. All ocular procedures should be performed under anesthesia with the patient intubated and full anesthetic monitoring in place.
As with any trauma patient initial assessment of all body systems is vitally important and stabilization efforts should be performed as usual. Attention to respiratory status is important. Any wound care procedures that require debridement and surgical repair should be done under general anesthesia with intubation to control airway function and should be considered only after initial stabilization efforts.
Hyperthermia or heat stress
Hyperthermia and heat stress are common emergency presentations for brachycephalic breeds and can happen even in normal room temperature situations. It is very common for brachycephalic patients to become hyperthermic from mild exercise and activity, especially at ambient temperatures of 70 degrees and above. Hyperthermia can happen during play or restraint from veterinary procedures, bathing or nail trims (even at home). Immediate external cooling should be initiated with lukewarm water on the coat accompanied by fans, IV fluid therapy and avoidance of bedding until temperature is 102.5 degrees or less.
Hyperthermia and heat stress can lead to complications including coagulopathy and/or hypercoagulopathy, diarrhea/hematochezia, pulmonary edema, cerebral edema, seizures and death. Secondary effects of heat stress can present one to three days after initial hyperthermic event, and patients should be closely monitored in a hospital. Many patients require plasma transfusions and intensive in-hospital management after a hyperthermic event.
Upper respiratory infection
Brachycephalic felines are at risk for more profound respiratory symptoms when compared to cats of normal facial conformation. Respiratory pathogen testing is recommended to tailor specific therapy if there is a bacterial component. Careful attention to ocular signs and early intervention if corneal ulcers are detected is especially important. If patients are reluctant to eat due to severity of nasal congestion or associated pharyngitis, early intervention with esophageal tube placement for nutritional support and medication administration is recommended.
References and Suggested Reading
Fasanella FJ, Shivley JM, Wardlaw JL, Givaruangsawat S. Brachycephalic airway obstructive syndrome in dogs: 90 cases (1991-2008). J Am Vet Med Assoc. 2010 Nov 1;237(9):1048-51.
Gent, G. Companion Animal. 2013 Aug;18(6):271-276.
Hoareau, GL, Mellema, MS, Silverstein, DC. Indication, management, and outcome of brachycephalic dogs requiring mechanical ventilation. J Vet Emerg Crit Care (San Antonio). 2011 Jun;21(3):226-35.
Rozanski, E. Brachycephalics: What to Know and What to Do. Wild West Veterinary Conference 2015.