Mike, Well, I'm pretty opinionated on this topic but here goes anyway. I don't believe that a neurologist should be ordering PFT's for someone with MG. They are not a pulmonologist. Their "take" on PFT's may be accurate but it is NOT their speciality. Would you want a orthopedist to do open heart surgery or a podiatrist to check your eyesight or a proctologist to treat colon cancer?
That's not to say that BOTH doctors aren't important in your care. In fact, in a hospital setting, they are "forced" to work together for an MG patient.
Let me give you an example. Take MIP, maximum inspiratory pressure or what some call NIF, negative inspiratory force. It shows how well your chest wall muscles are doing at breathing in. That and MEP, maximum expiratory pressure (how well your chest wall muscles are doing at breathing out), are very specific tests for someone with a neuromuscular disease. What pulmonology techs often do is to take the highest number only. That doesn't work with MGers. Two days before my MG crisis, I had PFT's done. My MIP kept going downward with each successive sucking on that tube. It went like this: -61, -55, -43, -32, -31. The numbers "bottomed out" like I was about to. MG gets worse with sustained or repetitive activity, which is why a "trend" in those numbers is so important to look at.
Now a neurologist might look at that -61, the number the tech would've shown the pulmonologist if I let her, and proclaim that you're fine. It doesn't reflect the entire picture. At that point, my pulmonologist should've done ABG's (arterial blood gases) and a mini-neuro exam. Instead, I wound up with a full blown crisis two days later. My average normal MIP, which is important for an MGer to know, is about -84, not -31. At -21 or so, it's time to consider either a Bi-Pap or intubation, depending upon the clinical picture and things like O2 saturation and ABG's. Your tissues are not getting enough oxygen when a MIP or MEP get that low.
There are no simple answers to your questions.
Total lung capacity is important too. But knowing what your "normal" is cannot be underestimated. Any test numbers are relative. I've attached a few PDF's for you to read.
If you don't have a pulmonologist, that would be a good idea. I have one that is both a pulmy and a sleep specialist. That's important for an MGer too. Not all pulmy's are sleep specialists. They are the ones who evaluate you for a Bi-Pap and regulate the use of it. A pulmonologist can do some pretty amazing things for you, like order the use of O2 on an airplane if you need it. Of course, you'll have to have a video of an oximeter to "prove" how bad you get up there. They can also make sure you have O2 at home too if you need it.
Did any of the numbers you got, assuming you got a copy, show that you were below the percent of predicted numbers and what percentage you were?
I hope you get answers soon. Is your breathing worse lately? Just stay the heck out of the hot weather. It was 103 here yesterday and I didn't even consider going out.
Annie