Noises in the Night

I am still using a ventilator at night to help my breathing since I was in hospital in 2007.    The ventilator I use is called a Respironics PLV-100 as shown in the picture.  Once a year the respiratory therapist brings a replacement ventilator so the one I have been using can be sent away for servicing.   On Tuesday  I got my ventilator changed and used it that night.  I had tried it out  for a while during the day and it sounded and felt fine.  It has a moderate rhythmic breathing sound when operating.  But 15 minutes after I went to bed the machine started making strange noises, kind of a scraping and rattle and intermittent knocking.  I tried to ignore the sounds and get some sleep but was mostly awake until after 4 AM.

Then Wednesday morning I called the respiratory therapist and he brought me another replacement ventilator.  I tested it for over half an hour  before supper to make sure it was working normally.  I went to bed that night and all seemed well.    I woke up at 2 AM to the ventilator making sounds like a cricket chirping.  This time I shut it off and turned it back on and it quieted down to normal sound.  After a while I got back to sleep but at 4 AM the cricket sounds were back in the machine.    I got it quieted down again and got some sleep before the cricket sounds were back at 6 AM.  I fell back to sleep then until 8AM and awoke to a quiet ventilator.  

I emailed the respiratory therapist to report the latest in the noisy ventilators saga.  He still has the one I was using for the last year and will bring it back if I continue to have trouble with the replacement machines.  We will see what happens tonight.   I hope all is quiet in the machine so we can get a good nights sleep.