Breathlessness

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If there is insufficient oxygen or too much carbon dioxide in the blood, respiration is stimulated. This may result in an increase in the respiratory rate or in more effort being required for each respiratory movement (indicated by greater observable movements of the chest wall and possibly the abdomen). The dog may adopt a posture that helps air pass through the airways – sitting upright with the neck stretched out and the elbows rotated outwards. They may avoid lying down and so appear to be unable to rest.

Rapid respiration can also result from fever or pain.

Breathlessness can result from anything that affects levels of oxygen and carbon dioxide in the blood, but is most commonly associated with blockage of the airways, disease or damage to the lung or other structures within the chest cavity, or disease / damage of the heart. This is potentially a sign of life threatening disease and veterinary advice should be sought without delay.

The problem may be more common in breeds with shortened snouts (brachiocephalic dogs) such as bulldogs, pugs and Pekingese. All the normal anatomical structures are squashed into a smaller space so the airways are relatively narrower and the respiration compromised.

What your veterinarian will want to know

Your veterinarian will want to know if this has occurred suddenly or whether it has come on gradually. If it was sudden, did anything appear to trigger it – such as exercise or a high ambient temperature? If there was a gradual onset, is it getting worse?

Are there any other symptoms such as a cough, weakness or collapse? Is there an associated swelling of the abdomen? Is your dog eating? Is he depressed or crying out as if in pain?
The lung is a common site for secondary tumours. Have there been tumours removed from other areas of the body in the past?

What your veterinarian may do

A full clinical examination will indicate whether there is a raised body temperature or the presence of pain. Checking the colour of the membranes of the eyes and inside the lips, together with feeling the strength and character of the pulse will help to give an indication of the state of the circulation.

Watching the speed and extent of chest movements will help to assess the degree of difficulty the dog is experiencing when breathing. Listening to the chest with a stethoscope (auscultation) is very important. Heart sounds are usually easily detected on both sides of the chest. Abnormal sounds may reflect leaky valves within the heart or narrowing of the main arteries. Muffled heart sounds may result from fluid (or solid tissue) between the heart and the chest wall. The sound of the air passing through the lungs may be detected, indicating the presence of narrowing of the airways or abnormalities within the lung tissue.

The lung should normally be filled with air, so tapping the chest wall (percussion) should give a resonant sound like a drum. Dull muffled sounds might result from fluid or solid masses within the chest.

The clinical examination will give your veterinarian a lot of clues about the potential problem. Depending on his findings, he may wish to carry out further tests such as X Rays, ultrasound or blood tests. If there is free fluid present within the chest cavity or in the area surrounding the heart, it may be useful to take samples of this for laboratory analysis. Samples of solid masses (biopsy) can also often be taken using ultrasound. Some of these procedures may require sedation or anaesthesia.