Well, Don, I don't have COPD, but I have two sister lung diseases, asthma and bronchiectasis. Like COPD, these both interfere with the ability of lungs to clear out mucus, which leads to opportunistic infections settling into the nice, warm, moist, dark environment that is our lungs. Many of us in the Bronchiectasis group use one daily as part of our "airway clearance" to keep infection away. (you can see a video about it here: https://www.youtube.com/watch?v=L-EHohMe7II )

What an OPEP (Oscillatory positive expiratory pressure) device does is cause vibration which loosens the mucus to make it easier to cough out. There are some relatively inexpensive ones on the market, some of them covered by Medicare Part B as a medical device. Two I have used are Aerobika and Acapella (https://www.vitalitymedical.com/acapella-vibratory-pep-mucus-removal-therapy-valve-smiths-medical.html)

I use a 7% saline neb, followed by using the vibratory device, which makes me cough up a ton of mucus. On days when I skip the process, I find myself coughing up thick mucus off and on all day long. Doing this has also kept me from getting pneumonia and bronchitis for almost 2 years (previously I could count on 3-4 bouts every year.

There are also so elaborate systems that combine nebulizing with OPEP vibration - I haven't used them, so I cannot speak to effectiveness. I'm going to invite another Don @thumperguy to talk abouthow airway clearance has helped him.

Does this help you understand what you might be able to do to breathe easier?

Sue