@ncalvan - I hate to discourage travel, or sound like "Negative Nellie", but unless you are accustomed to high altitude, I believe you need to do three things before January -
First, consult with your care team - although Machu Picchu is at about 8000 feet, the tourist venue of Cusco is nearly 12,000 feet - high altitude for even healthy lungs. Based on your lung capacity, and the added burden of medications, this could be a risky plan.
Second, find out IN ADVANCE where you can find medical care for your lungs if you need it. Remember, you are out of the US and may have insurance coverage issues and language barriers to getting care. And it won't be "like home"...
Third, find out if your travel insurance will cover you in the event of an emergency, since you have a preexisting condition. And remember, if you are having lung issues, commercial airlines may decline to fly you until you are medically cleared, resulting in delays and unexpected stays in an unfamiliar country.

I am saying this as someone who had serious altitude sickness at 8000 feet in Yellowstone while on the Big 3. I had previously visited there, and other mountains up to 10,000 feet with a few days of acclimatization, without any problems. I will be trying again next summer after 4 years off antibiotics, with routine O2 sats of 95-97%, but will approach the higher altitudes slowly this time.
Sue
PS My fit 30-something daughter and son-in-law both struggled with the altitude in Cusco