Ask a Dog Vet and Get Answers to Your Dog Veterinary Questions
Can you describe the cough? There are many reasons that dogs cough. The rapid breathing when he sleeps is worrisome as dogs with heart disease can have fluid build up in their longs that causes them to need to breathe faster in order to oxygenate properly. One of the way we monitor dogs with heart disease is by monitoring a sleeping respiratory rate and counting the number of breaths in a minute. A breath is counted as one each time the chest rises and falls. If it is more than 40-45 breaths per minute, then that warrants veterinary attention. Are you able to take a sleeping respiratory rate on your dog?
It sounds like the best thing to do is to have him evaluated by a veterinarian to look for things that cause coughing in dogs, especially if his sleeping respiratory rate is higher than about 40-45 breaths per minute.
Do you have further questions that I can help with?
An off color tongue makes me concerned that he is having trouble breathing and cannot oxygenate his tissues properly. A severe collapsing trachea can cause this as well and if this is a severe attack, sedation is required to help reduce anxiety and calm him down enough that he can breathe normally. My best recommendation in this cast is to have him examined by your vet to determine the nature of his cough and what can be done about it. If he is currently having this issue, then he should see an emergency veterinarian however if he is able to breathe at the moment then you can call your veterinarian and make an appointment to have him checked out.
In the meantime, keep him calm, prevent him from becoming overheated and use a harness to walk him on a leash instead of a collar.