I do not think they have "puffers" for dogs. Walk frequently, for shorter periods. No running and long walks. Keep the heart rate down. Don't overexert.
Try and figure out what is triggering your dogs asthma, for example dust,and smoke. Also your vet can prescribe anti histamines what will also help with the symptom
You call a Vet and make an appointment and tell the vet what you think he has. He will advise you what you should do. Maybe a air cleaner in the home will help.