Reducing the risk of anaesthetic complications in patients with brachycephalic obstructive airway syndrome

The aim of this article is to highlight the main complications when anaesthetising dogs with brachycephalic obstructive airway syndrome (BOAS) and to provide clinical techniques to reduce instances of complications.

BOAS is a combination of abnormalities of the upper respiratory tract in dogs that can result in obstruction of the upper airway and dyspnoea. Abnormalities include stenotic nares, elongated soft palate, hyperplastic tonsils, everted laryngeal saccules, laryngeal collapse and hypoplastic tracheae. In addition, some patients can have a concurrent sliding hiatal hernia. Affected dogs may have a combination of these disorders, resulting in varying degrees of upper airway obstruction (Figure 1).

Commonly affected breeds include Pugs, Boston Terriers, English and French Bulldogs, Pekingese, Shih Tzus, Boxers, Bull Mastiffs and Cavalier King Charles Spaniels.

Clinical signs include, inspiratory stertor, stridor, exercise intolerance, gagging, regurgitation, vomiting, syncope, and dyspnoea. Clinical signs occur at varying degrees of severity, from mild nasal airflow obstruction to severe airway occlusion. Patients can also suddenly deteriorate when in a stressful situation such as exercise and excitement and may require emergency treatment for severe dyspnoea and cyanosis. The hospital environment can be stressful and care should be taken to make it as quiet and stress free as possible for patients with BOAS.