In the last 30 + years of haveing COPD I Have. With COPD if you pass out, your body will relax and you will breathe. When you wake I suggest you call your Dr. or go to the ER IF You feel you need to. It's also a Panic Attack which can be headed off with Dr. prescribed Xanax. I would suggest the brand that dissolves under your tongue. Fast acting, I cough as hard as I can and exercise as often as possible on purpose to get the phlegm to break loose from inside my lungs so I can cough it out. Mucinex 1200 mg twice a day with a glass of water will help it break loose, I use it every day.
God Bless You and Remember: Trust God, Slow Down and Breathe Eazy :-) .

Ditto I have done that also.

I had a lot of tests two CT Scans head and chest with contrast. all blood work was good except it looked like I was dehydrated. They called it COPD exacerbation.

This is what I love about the Q&A, there is so much experience and advice and support. 😀 You can use what is helpful and although I wouldn't wish this disease on anyone, it's always a relief to realize you are not the only one this happens to.

That is what I have ben told will happen. I haven't had it happen yet but have been very close. My Dr always says to let him know about it.