I just signed on and saw your question has not been answered. I hope this response is still helpful. The following site goes over heimlich for dogs.
If your dog is panting there are many different things can cause constant panting. Heavy panting can be caused by heart problems, lung problems, fever, or bronchitis. You can read about this here:
Dogs pant for various reasons. They pant to cool down, but they also pant when they are under stress, in pain, or afraid. There can also be medical causes such as neurological problems, respiratory disorders, and Heart problems such as heartworm, anemia, and fever.
If your dog is indeed having difficulties breathing, she should be taken to the vet immediately. Allergic responses can cause swelling of the throat and need to be addressed prompltly. If this is the case, Benadryl can be given to your dog, the dose is up to 2mg per pound every 8 hours.
You can read about these here.
If you think this might be a severe cough, there are things you can do to help. To help your dog breathe easier you can run a NON-medicated humidifier in the room your dog is in, or sit in a steamed up bathroom with your dog to help keep the mucous moving. Robitussin DM at a 1/4 teaspoon per 5 pounds can be used to control the cough. Dosages can be obtained at this website. http://www.petplace.com/drug-library/dextromethorphan-robitussin-dm/page1.aspx
Again, if your dog is having difficulties breathing she should be seen by your vet immediately. Hope this helps.
Edited by Jane Lefler on 2/3/2010 at 12:35 PM EST