@doberdoo. Did your Pulmonologist give a reason for not prescribing saline? Most all of us on this Mayo Clinic Site do nebulize and most all pulmonologists recognize it's importance for assisting in the clearance of sputum from your lungs. Was there a connection to your heart issue?
Funny....My first pulmo said no to saline when I asked for it so I asked my GP to write a prescription while I looked around for a new Pulmonologist. And I did make an apt with Mayo Clinic for a second opinion while searching for a new local Pulmo. I saw a terrific Dr at Mayo, who said that I most certainly should nebulize 2 times a day.
Not sure why Dr McShane does not like on-line saline but perhaps because it is not a pharmaceutical grade of saline that might have impurities. ?(only a guess). Without sounding too judgemental, you might look around for a new Pulmo who has expertise with Bronchiectasis and MAC.
There are also many great posts on this site. After my diagnosis, I first landed here, where I got good sound advice and guidance.
Again....wishing you good health going forward. Kate