My mom is a cancer survivor and has had breast, melanoma, and lung cancers - all separate incidences. In 2005 she had part of her lung removed surgically and had both chemo and radiation.  Although she is doing OK - she still has cancer in both lungs though rather slow growing.  This past fall, she was put on a chemo regimen every 3 weeks.  Her fatigue level was high and she was not feeling well so the dr approved a "chemo holiday".  Also - she has sleep apnea and uses a cpap machine/mask.  Recently she coughed up quite a bit of blood and wound up in the hospital.  After a broncoscopy, the dr determined that she had a fungal infection in her lung cavity and is now on medication.  Could the CPAP be the source of that infection & if so, how can we avoid that?
Unfortunately due to your mothers weak immune system (due to the chemotherapy), fungal infections can run rampant in the lungs and cause bad pneumonia. Most of these fungi are present everywhere around us in the environment. While it is unlikely that the CPAP machine was the source of this infection, it should be regularly cleaned. You should refer to the manual that came with her specific CPAP machine for further instructions on how to clean the mask and tubing.