You should seek the advice of your veterinarian if your pet is ill as only he or she can correctly advise on the diagnosis and recommend the treatment that is most appropriate for your pet.

The rational treatment of dyspnoea requires an understanding of the underlying mechanisms involved

Difficulty in breathing (dyspnoea) is one of the commonest signs of heart failure, as well being a symptom of respiratory diseases. Signs associated with cardiac dyspnoea include  :

• Increased respiratory rate
• Shallow breathing
• Noisy breathing *
• Cough *
• Frothy sputum (sometimes blood-stained) *
• Fast, irregular  pulse* 
• Cyanosis*
• Low body temperature*

* Seen especially  in acute pulmonary oedema secondary to cardiac disease

Dyspnoea in cardiac disease is usually gradual in onset, but there can be sudden onset in some cases, for example if there is atrial fibrillation.

Dyspnoea in cardiac disease may be due to any of the following :

• Reduced pulmonary capacity (vital capacity) due to congestion, hydrothorax or ascites
• Reflex hyperventilation due to abnormal stretching of receptors by congestion of the lungs
• Bronchial narrowing  - due to bronchospasm or fluid
• Hypoxemia - reduced oxygenation of red cells, for example in pulmonary oedema. Severe hypoxemia is indicated by cyanosis.
• Increased carbon dioxide tension due to impaired gaseous exchange through the lungs. This causes a reflex increase in respiratory rate.

Rational treatment involves :

• Remove fluid accumulations - diuretics
• Dilate constricted bronchi - bronchodilators
• Reverse hypoxia in cyanotic patients - oxygen
• Treatment of underlying cardiac disease to improve cardiac output, pulmonary circulation and reduce pulmonary congestion. All of which improve pulmonary function.

Updated January 2016