BIPAP Central Apneas Appearing High AHI

[tmtyler357]

So I've been using my bipap for about a year with the pressures now at 15 inhale and 8 exhale. I was doing great and having no problems with it, AHI was very low, often 2 or lower. Now I've started experiencing what the machine calls central apneas, giving me an AHI of anywhere from 12 to 34. I asked my doctor and he told me that he believes most cpap/bipap machines to be very inaccurate and dismissed it as nothing to worry about. Meanwhile I'm still very tired and I don't feel like it's working as well as it once did. I'm definitely worse when I don't wear it, but even when I do wear it, I don't feel much better.

I've compared my central apneas to what a real central apnea looks like in a sleep study and they appear to be real, to me anyway.

I also have a rare neuromuscular/autoimmune disease called myasthenia gravis that disrupts the communication between the nerves and the muscles causing muscle weakness. This can also cause respiratory weakness.

The only thing different was that I switched masks in April to an Amara View (that I absolutely love). I checked and I was experiencing centrals before I switched masks too, not as often, but occasionally.

My AHI last night was 33, of which 31 were centrals.

I really like my doctor, but I think he's wrong. I want him to do another sleep study to be positive these are or are not real. I gave his secretary some reports from sleepyhead and she was more concerned than he was. She was going to fax them over to him right away. That was Thursday morning. I'm hoping I hear back from him next week, but something tells me he doesn't want to do anything about it.

Here is a screenshot.

[Wulfman...]

Try going back to the mask you were using before this one. See if there are any similarities or differences.....now.


Den

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[tmtyler357]

I'll try that tonight and reply back tomorrow.

Thanks!

[Julie]

Hi, hope you don't mind my asking, but when's the last time you did have an MG check... e.g. EMG or ?? Because it is progressive as you must know and if your muscles are not as strong as they used to be, you need to know, not just for the sake of Cpap, but all around.

[tmtyler357]

I haven't had another EMG or SFEMG, but I recently saw my neurologist, everything was okay in the office (nice and strong). Outside of the office I'm still weak and have a difficult time with most daily tasks. But we are treating it...oh wait, one other thing has changed since most of this got worse, we decreased the prednisone from 10mg every other day to 5mg every other day. But we also increased my cellcept (waiting for it to kick in still). I've been on cellcept over a year but each time you change the dose it takes about 6 months to see the full effect of the new dose. I'm on 3,000mg of cellcept a day.

[palerider]

I asked my doctor and he told me that he believes most cpap/bipap machines to be very inaccurate and dismissed it as nothing to worry about.

the term "ignorant fool" comes to mind when considering your doctor. you've zoomed in, you can *see* the breathing patterns, you can *see* where you stop breathing.

I really like my doctor, but I think he's wrong.

a friend of mine 'liked' his doctor, old folksy one, doc kept brushing off his chest pain, shortness of breath and terrible lethargy as a hiatal hernia, never bothered to do tests. unfortunately, his cpap at the time didn't provide flow data like yours does. I loaned him a machine with full data, saw extended sessions of CSR... told him to get to a REAL doctor, post haste,.... end result, he had *severe* congestive heart failure.... goood old 'doc nearly friendlied him into an early grave.

[tmtyler357]

I think if he doesn't call me back, I'm going to call him and demand another sleep study to be sure. I honestly think it's the myasthenia gravis causing it. It can cause decreased respiratory drive so it's definitely a possibility.

What should I do if he still refuses another sleep study? I have my PCP, but she most likely wont go behind his back to do it. He's the only sleep doctor within 2 hours of my location and he's in charge of the sleep center at my local hospital.

[palerider]

I think if he doesn't call me back, I'm going to call him and demand another sleep study to be sure. I honestly think it's the myasthenia gravis causing it. It can cause decreased respiratory drive so it's definitely a possibility.

What should I do if he still refuses another sleep study? I have my PCP, but she most likely wont go behind his back to do it. He's the only sleep doctor within 2 hours of my location and he's in charge of the sleep center at my local hospital.

have you had your ticker checked recently?

[Wulfman...]

I think if he doesn't call me back, I'm going to call him and demand another sleep study to be sure. I honestly think it's the myasthenia gravis causing it. It can cause decreased respiratory drive so it's definitely a possibility.

What should I do if he still refuses another sleep study? I have my PCP, but she most likely wont go behind his back to do it. He's the only sleep doctor within 2 hours of my location and he's in charge of the sleep center at my local hospital.

"I feel your pain......."
Same story here. I'd probably be in a world of hurt if I "needed" to see a sleep doctor again and/or had to go back to the SOB I had 11 years ago. We didn't exactly hit it off......and, I had been forewarned by others who had been to him before I met him, too.


Den

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[tmtyler357]

I think if he doesn't call me back, I'm going to call him and demand another sleep study to be sure. I honestly think it's the myasthenia gravis causing it. It can cause decreased respiratory drive so it's definitely a possibility.

What should I do if he still refuses another sleep study? I have my PCP, but she most likely wont go behind his back to do it. He's the only sleep doctor within 2 hours of my location and he's in charge of the sleep center at my local hospital.

have you had your ticker checked recently?

I have not had my heart checked recently. I had an EKG about a year ago I believe, and an echocardiagram and stress test about 3 years ago. I also had an MRI of my chest about a year ago. There hasn't been any concern or need to have it checked again lately. I've been doing very well in that department. I'm pretty sure it's the MG causing it.

Also, switching masks made no difference. AHI last night was 25 and CAI was 23.

[tmtyler357]

Well I got my doctor to order another sleep study. He ordered a bipap titration. The tech told me I had 2 central apneas that were real and a bunch of others that could have been flagged if the machine is scoring under 10 second apneas too, which I now believe it might be. The data in SleepyHead shows the machine marked say 250 centrals in a night, but upon inspection most of these are under 10 seconds. Why would my machine be scoring apneas under 10 seconds? I also compared it with DreamMapper and the AHI/Count is the same as SleepyHead.

The tech also told me that my original pressures worked perfectly. 13/9. We originally had increased the inhale pressure to 15 because I was still waking up gasping for air and decreased the exhalation pressure because I had a difficult time breathing out due to the MG.

I'm assuming my doctor will change my pressure back to 13/9, but I don't know yet. I'm also assuming that my current pressures could be too high thus causing the centrals.

I woke up around 3:30am and couldn't fall asleep again. At 5am the tech said he had enough data and I could go home if I wanted to or wait another hour. I went home early.

Thank you for the help everyone!

[Pugsy]

. The data in SleepyHead shows the machine marked say 250 centrals in a night, but upon inspection most of these are under 10 seconds. Why would my machine be scoring apneas under 10 seconds?

Because the machine thinks they lasted at least 10 seconds. Sometimes it is real hard to zoom in and count the seconds because it's hard to know exactly when the machine thinks the "event" began and ended.
I suspect that where you think it is beginning and ending isn't the same as what the machine is thinking.

Also...are you by chance going by the little number in parentheses thinking that it means duration? It doesn't with the Respironics machines like it does with the ResMed machines. Respironics machines don't give us event duration. The number in parentheses isn't technically event duration in seconds...it's close but not exact and that's why SH will show a number less than 10 sometimes in those parentheses. They are markers of some sort and Mark (who wrote SH) decided to include them because they were real close but they aren't exactly the number of seconds. I spent a lot of time counting the seconds for a lot of flagged events and the ones with 6 or 7 or 8 or 9 in parentheses were all real close to barely making the 10 second criteria. Again its real hard to determine the exact beginning and ending when counting the seconds at that level of zooming in.

SleepyHead can only report what the machine is reporting...it doesn't/can't change the criteria for a machine flagged event. It's the machine doing the flagging and that's why SH and DreamMapper are reporting the same thing.

[tmtyler357]

Yeah, I've noticed some of the "centrals" when you hover over them it highlights where they began or where the machine thinks it began. Sometimes it overlaps my breathing pattern, sometimes it doesn't. I've also noticed that the flag is directly in the middle of most of the events duration. If I stop at the marker it is clearly not 10 seconds long not even close even when the number in parenthesis is over 30. But if I go past the marker to just before I start breathing again it might be close to the number in parenthesis.

I had read that as I wondered what the number in parenthesis means. I have the PRS1 60 Series.

Comparing SleepyHead and DreamMapper is how I figured out that it was the machine doing the flagging.

Do you think the pressures I have are too high and that could cause the centrals? I ask because when we started the therapy a year ago, my numbers were excellent, always under 5 with little or no centrals. In September we changed the pressure from 13/9 to 15/8. It was around April when the "centrals" began appearing and more recently that they started to cause me some concern.

[Pugsy]

I have no concrete idea if the higher pressures are the cause of the centrals or not but I do have an idea about the higher PS Pressure Support which is the difference between inhale and exhale.
Sometimes there is a line in the sand where centrals pop up above that line and below it they don't when it's strictly related to pressures like the 15 vs the 13.

BUT...this just caught my eye...you say pressures are 15/8...please clarify if you mean 15 inhale and 8 exhale...if that is the case then that means a PS of 7 and sometimes when PS is a bit high (or a lot high) it causes a person to blow off too much carbon dioxide and the brain gets fooled into thinking it doesn't need to breathe because the carbon dioxide levels never get high enough to trigger the brain to tell the body "breathe stupid"
It actually the high carbon dioxide level that is the trigger for the brain and not low oxygen. I have seen people have a lot of centrals when they are using bilevel with the PS being over 6...you might be one of them.
When the difference between inhale and exhale is a lot it makes us sort of hyperventilate which causes the carbon dioxide to get blown off too soon so it doesn't build up in the blood stream and without it increasing the brain doesn't know it needs to send the "breathe" command.

If they went from 13 inhale and 9 exhale (that's PS of 4) directly to 15 inhale and 8 exhale in an effort to make the breathing easier it's not impossible for that big of a PS to be the cause of the centrals.
Did you ever try anything in between? Maybe with 5 PS instead of 7?

If it were me...I would reduce the PS and see if that reduces the centrals...if 13/9 is a little difficult maybe try 13/8 so that PS is only 5. Or 14/9 maybe...keep the difference 5 cm and see if that is comfortable enough without risking that sort of hyperventilation thing.

Simple enough to try and you might get lucky and find a real simple answer as to why the centrals suddenly appeared. I have seen it several times when people with bilevel machines get kinda gung ho on playing with the Pressure Support. Now sometimes there is a medical need for a higher PS but those people usually have some sort of lung issues going on and when that happens the lung condition itself helps keep the carbon dioxide from getting blown off too soon and it doesn't cause them to have centrals.

So I would reduce PS to something closer to that original 4 and see what happens. It wouldn't be impossible for your centrals to be caused by the Pressure Support and in fact I think given the higher than usual PS you went to...the chances would be greater for PS to be the culprit than it would be that change to 15.

[tmtyler357]

Thank you so much for the great explanation and information.

My doctor did have me go straight from 13/9 to 15/8 (15 inhale/8 exhale same with the 13/9).

That was my thought and the technologist's thought too that I'm blowing off too much carbon dioxide.

I'm sure my doctor will have the DME change the pressure back to 13/9, which I didn't notice any difficulties with this time. It might be because my respiratory strength has improved a little with the myasthenia gravis treatment since last year.

I'll post back after I hear from my doctor and have the changes made. I'll check my data and report what it says then, about the centrals.

Thanks again! You are a great wealth of knowledge and I appreciate the feedback.

On an unrelated note, my machine will not show up in my signature, but the humidifier, mask, and comment do. It's set in my profile but it just doesn't show for some reason.