My Neechee had chronic bronchitis when he was 15. At that time, I moved and changed vets. I have asthma and take nebulizer treatments just about every day, so I asked the vet about using the nebulizer for him. We rigged up a hood type thing from an anesthesia muzzle, and Neechee and I took our treatments together. I just watered down my usual albuterol solution and took it in two doses - Neechee joining me for only the first one. It really helped him, and eventually he quit coughing altogether. (He lived almost three more years cough-free.)
If you have access to a nebulizer, ask your vet about using it to give your dog treatments. It really does help them, and all you must do is make them sit still. One word of warning, though. Albuterol will make a dog extremely hyper sometimes!