Low Blood Oxygen Levels Despite Usint BiPAP

I was diagnosed with central and obstructive sleep apnea about one year ago.  My first CPAP machine did not resolve my symptoms and I was switched to a Respironics Auto SV BiPAP machine w/ two liters of oxygen about four months ago.  I had an overnight pulse oxygen test last week.  The results show that I had two periods between 30 and 45 minutes where my blood oxygen level fell into the low 80s and even the upper 70s.  Is an hour to hour and a half of low blood oxygen a problem?  What are the possible effects?  And, could it explain why I am still tired.  And lastly, if I'm using my BiPAP, then why would the O2 levels drop so dramatically.

Thanks very much.

[KatEyes]

Couple things ... are you using a full face mask? If not, mouth breathing can compromise one's treatment. Is your doctor getting readouts of the data from your machine to see if the settings are therapeutic and preventing your apneas?  If your pressures are not effective, it could offer some explanation for the low oxygen. There is a website that addresses a wide range of machine issues. You may glean some helpful info there at cpaptalk. If all is right with your treatment, you may need further testing to discern if there is something else going on with your lungs. You may even need another sleep study while on the bipap to evaluate how it's going, but the data output from your machine should at least give an idea.

[Curtis1960]

KatEyes, thanks so much for responding.  I am using a full face mask as I am primarily a mouth breather.  My BiPAP machine is an auto version and the pressures change depending on the number of apneas I am experiencing.  My treatment data is sent to my doctor every few months but I don't really think he looks at it.  In fact, my doctor doesn't listen to anything I tell him.  Here in Colorado Springs there are few sleep specialist MDs. I read the data myself and it appears that the BiPAP machine is doing its job.  And, my insurance has already paid for four sleep studies and won't pay for another.  This is why I am asking these questions in this forum.  I do agree that it may be something else besides apnea that is causing the problem.  I'll talk to my regular MD and see what he says.  Again, thanks for answering my question.

Cheers,

Curt

[jimgreg]

yes it can make you very tired cuz wile ur asleep ur hearts being robbed of all the needed oxegen..and have you had ur blood pressure checked lately?? that why ur tied at daytime..

[Curtis1960]

Hello, Jimgreg.

Yes, I had my blood pressure checked in August and it was 100/60 with a resting pulse of 55. I had been walking 6 - 9 miles a day until I had ankle sugery in August and my blood pressure came down dramatically.  

[mesch]

I have been on a bi-pap for a year now.  I was still exhausted. I happen to work with a Nurse Practitioner and she noticed how exhausted I was.  She took blood work and it appears that my iron is very low so, this causes you to have less oxygen in the blood.  The iron pills seem to be helping.  Just a thought.