I took Max to the vet this morning. They did blood work, x-rays, etc., and gave him a full exam. At this point, they think his shortness of breath is being caused by fluid around the lungs, which is causing pressure within the chest cavity. I didn't see the x-rays myself (I didn't want to), but the doctor said the lesions in his lungs are much larger. He's not in pain, but he's uncomfortable and not breathing easily.

The doctor at the office today isn't our normal vet, but she's going to call her and do a consultation. We'll trust their judgment. The long and short of it is this - they think they can drain the fluid using ultrasound (I have no idea how that works), which will alleviate the pressure. The problem is that they also think the fluid is likely to return within a few days. This isn't something that's going to go away, and so the ultrasound may end up being little more than trying to hold the ocean back with a broom.

So we're waiting to see what our two doctors come up with. Di and I agreed a long time ago that we won't have Max in pain even for a second longer than he has to be. We're not giving up yet, but the vet isn't liking what she sees. I'll keep this thread updated as best I can as new developments occur.