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Confusing sleep study results - pressure?
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sir_sleeps_alot Offline

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Machine: ResMed S9 Autoset
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CPAP Pressure: 14 cm h2o
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Location: New England

Post: #1
Confusing sleep study results - pressure?
I am confused by sleep study results. I am diagnosed with severe obstructive sleep apnea that resolves on cpap and moderate to severe persistent hypoventilation.

The only apneas I had were central and only occured during the cpap titration portion of my test. My AHI pre-cpap was 105 due to hypopneas only.

During the cpap titration, I show no hypopneas at all, at any pressure. At 6cm H20, my AHI is 4.1 due to central apneas. From 6 - 12, my AHI is zero. At 12cm H2O, my AHI jumps to 17 due to central apneas. This is the only time I had REM sleep. My AHI goes down to 0 at 13 and then to 3.4 AHI at 14cm H2O. This is where the chart ends.

One of the recommendations from my study is that I use a cpap at a pressure of 14cm of H2O.

Are there any dangers w/ a higher vs. lower pressure? Is it possible that my breathing muscles could become weak?

Given that my hypopneas resolve with minimal cpap pressure, does it seem reasonable that my pressure should be set at 14cm H2O?

Is cpap effective on central apnea?

Is there any way to my central apnea stopped due to the cpap pressure vs. me no longer being in REM?

Is it possible that I need a pressure higher than 14cm H2O to resolve the apnea I was having during REM?

Am I getting too caught up looking at little values when I need to be looking at the big picture?

The recommendations from my sleep study included the suggestion that I try bpap for my hypercapnia (high CO2) if I'm having morning headaches or confusion. I don't have morning headaches but I do reliable get one pretty much every afternoon. Any chance bpap would help with that? The NP who reviewed my results didn't even mention the bpap.

Given that my O2 sats are adequate on cpap, should I be concerned that my CO2 remains high?

I really wish that I'd been able to see my sleep study results before having my post-sleep study consultation with the doctor. I would have asked all my questions then. Smile

I'm not looking for medical advice, as I already have plenty... just looking for different perspectives and a better understanding.

Thanks!
Sid
10-15-2013 11:38 PM
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me50 Offline

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Machine: resmed S9 VPAP Auto
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Post: #2
RE: Confusing sleep study results - pressure?
(10-15-2013 11:38 PM)sir_sleeps_alot Wrote:  I am confused by sleep study results. I am diagnosed with severe obstructive sleep apnea that resolves on cpap and moderate to severe persistent hypoventilation.

The only apneas I had were central and only occured during the cpap titration portion of my test. My AHI pre-cpap was 105 due to hypopneas only.

During the cpap titration, I show no hypopneas at all, at any pressure. At 6cm H20, my AHI is 4.1 due to central apneas. From 6 - 12, my AHI is zero. At 12cm H2O, my AHI jumps to 17 due to central apneas. This is the only time I had REM sleep. My AHI goes down to 0 at 13 and then to 3.4 AHI at 14cm H2O. This is where the chart ends.

One of the recommendations from my study is that I use a cpap at a pressure of 14cm of H2O.

Are there any dangers w/ a higher vs. lower pressure? Is it possible that my breathing muscles could become weak?

Given that my hypopneas resolve with minimal cpap pressure, does it seem reasonable that my pressure should be set at 14cm H2O?

Is cpap effective on central apnea?

Is there any way to my central apnea stopped due to the cpap pressure vs. me no longer being in REM?

Is it possible that I need a pressure higher than 14cm H2O to resolve the apnea I was having during REM?

Am I getting too caught up looking at little values when I need to be looking at the big picture?

The recommendations from my sleep study included the suggestion that I try bpap for my hypercapnia (high CO2) if I'm having morning headaches or confusion. I don't have morning headaches but I do reliable get one pretty much every afternoon. Any chance bpap would help with that? The NP who reviewed my results didn't even mention the bpap.

Given that my O2 sats are adequate on cpap, should I be concerned that my CO2 remains high?

I really wish that I'd been able to see my sleep study results before having my post-sleep study consultation with the doctor. I would have asked all my questions then. Smile

I'm not looking for medical advice, as I already have plenty... just looking for different perspectives and a better understanding.

Thanks!
Sid

Did your doc have the sleep study results when you had your post sleep study consult?

It is my understanding, and if I am incorrect, I am sure someone will correct me, that CPAP doesn't help Central Apnea. You said that you were not diagnosed with Central Apnea though.

I am sure someone else will be able to answer the rest of your questions. I hope you get your answers soon. Maybe you can make another appointment with your doctor and go in with a list of your questions.

Sorry I couldn't help you more.
10-16-2013 01:40 AM
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sir_sleeps_alot Offline

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Machine: ResMed S9 Autoset
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CPAP Pressure: 14 cm h2o
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Location: New England

Post: #3
RE: Confusing sleep study results - pressure?
My results were explained by a nurse practitioner who had my sleep study results in front of her. Per the sleep study report and the nurse's explanation, I have obstructive sleep apnea.

I had no apnea of any kind during the first part of my sleep study. I was dxed instead based on the an excessive number of hypopneas observed. My understanding is that hypopneas are not categorized as central vs. obstructive (or at least they were not in my case). My diagnosis of obstructive apnea seems to be based upon the fact that my hypopneas and desats resolved during cpap treatment.

Pre-CPAP AHI = 105
"Treatment" AHI (w/ CPAP) = 0 - 4.1 (depending upon the pressure)

Hypopneas resolved at lowest cpap pressure. Central apnea started at a pressure of 12 and resolved either due the pressure being raised, REM ending, or both.

I definitely have some form of sleep apnea, but I am curious as to how they arrived at the "obstructive" label I do not snore and my AHI/desats improve when I am on my back (both indicated by the sleep study) but I am overweight. I really can't question the fact that I improved dramatically on cpap.

Thanks for the advice! Additional input definitely desired. I'm not entirely sure if my insurance will cover another appointment, but I know I can always call and ask questions.

Sid

(10-16-2013 01:40 AM)me50 Wrote:  Did your doc have the sleep study results when you had your post sleep study consult?

It is my understanding, and if I am incorrect, I am sure someone will correct me, that CPAP doesn't help Central Apnea. You said that you were not diagnosed with Central Apnea though.

I am sure someone else will be able to answer the rest of your questions. I hope you get your answers soon. Maybe you can make another appointment with your doctor and go in with a list of your questions.

Sorry I couldn't help you more.

(10-15-2013 11:38 PM)sir_sleeps_alot Wrote:  I am confused by sleep study results. I am diagnosed with severe obstructive sleep apnea that resolves on cpap and moderate to severe persistent hypoventilation.

The only apneas I had were central and only occured during the cpap titration portion of my test. My AHI pre-cpap was 105 due to hypopneas only.

During the cpap titration, I show no hypopneas at all, at any pressure. At 6cm H20, my AHI is 4.1 due to central apneas. From 6 - 12, my AHI is zero. At 12cm H2O, my AHI jumps to 17 due to central apneas. This is the only time I had REM sleep. My AHI goes down to 0 at 13 and then to 3.4 AHI at 14cm H2O. This is where the chart ends.

One of the recommendations from my study is that I use a cpap at a pressure of 14cm of H2O.

Are there any dangers w/ a higher vs. lower pressure? Is it possible that my breathing muscles could become weak?

Given that my hypopneas resolve with minimal cpap pressure, does it seem reasonable that my pressure should be set at 14cm H2O?

Is cpap effective on central apnea?

Is there any way to my central apnea stopped due to the cpap pressure vs. me no longer being in REM?

Is it possible that I need a pressure higher than 14cm H2O to resolve the apnea I was having during REM?

Am I getting too caught up looking at little values when I need to be looking at the big picture?

The recommendations from my sleep study included the suggestion that I try bpap for my hypercapnia (high CO2) if I'm having morning headaches or confusion. I don't have morning headaches but I do reliable get one pretty much every afternoon. Any chance bpap would help with that? The NP who reviewed my results didn't even mention the bpap.

Given that my O2 sats are adequate on cpap, should I be concerned that my CO2 remains high?

I really wish that I'd been able to see my sleep study results before having my post-sleep study consultation with the doctor. I would have asked all my questions then. Smile

I'm not looking for medical advice, as I already have plenty... just looking for different perspectives and a better understanding.

Thanks!
Sid
10-16-2013 07:28 AM
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me50 Offline

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Post: #4
RE: Confusing sleep study results - pressure?
Your pre cpap AHI was 105 so you had some kind of apnea events. I am very confused by what you have posted. Do you have a copy of your sleep study you can share here? That might be more helpful in trying to help you understand your sleep study results.
10-16-2013 07:48 AM
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trish6hundred Offline

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Post: #5
RE: Confusing sleep study results - pressure?
Hi sir_sleeps_alot,
WELCOME! to the forum.!
Hang in there for more answers to your questions.
Best of luck to you.

trish6hundred
10-16-2013 10:04 AM
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skyler Offline

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Post: #6
RE: Confusing sleep study results - pressure?
Sir, I'd be confused too. I understand that cpap can initiate central apneas in people who normally don't have them as me 50 stated.. Your centrals don't seem high enough to warrant treatment, BUT you have a lot of other things going on that really need the attention of a first rate sleep doctor, and hopefully a pulmonologist, due to the complications of hypoventilation and hypercapnea. I know you just asked for clarification, but your case is far more complicated that we usually see.
Good luck. If you would fill in your profile as to machine we could help pointing our its data collecting capabilities- the form from the DME should state the model, or it should be on the machine. It would be great if you kept us up to speed on how you're doing.
10-16-2013 10:13 AM
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PaulaO2 Offline
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Post: #7
RE: Confusing sleep study results - pressure?
A sleep study is a good thing but it has a major flaw. It is one "night". The good parts is it can pick up on certain events, even in that short period of time.

Hypopneas are when the airway narrows and there is restricted airflow. I don't think you get that with central events. So that's why you got the diagnosis of obstructive.

It is a common thing for CPAP to cause central events but those almost always go away with time. Usually the patient starts out at a lower pressure then increases to the treatment pressure over time. Or uses an autoPAP.

You are brand spankin' new to this. Do what the docs tell you and give it a go. But demand a data capable machine. You want one that gives you and the doc actual data on how you are responding to treatment. Hours used is nice and all that but really, it's useless. It is akin to a doc saying "I don't want to know what your blood sugar readings are, I just want to know that you tested it 3 times a day".
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10-16-2013 12:27 PM
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Peter_C Offline

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Post: #8
RE: Confusing sleep study results - pressure?
I do know that centrals change with pressure as well, so it's a combo of where the centrals, REM sleep, and obstructive apneas are all three best at, not just where the numbers are lowest. You need REM sleep and a low AHI, etc... so I think that's where/why they landed on a pressure of 14...

*I* am not a DOCTOR or any type of Health Care Professional. My thoughts/suggestions/ideas are strictly only my opinions.

"Only two defining forces have ever offered to die for you. Jesus Christ and the American Soldier. One died for your Soul, the other for your Freedom."
10-16-2013 12:39 PM
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sir_sleeps_alot Offline

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Post: #9
RE: Confusing sleep study results - pressure?
Thank you for the comments and input thus far. Here's a bit more information:

I mis-stated my AHI in my earlier post -- I had 105 awakenings/arousals during the non-treated portion and 29 during treatment. My AHI pre-treatment was 87.7 and 5.0 post treatment. My AHI during REM sleep (w/ CPAP as this was the only time I had REM) was 11.3.

PSG Report:

Description: Lights were turned out at 11:43PM. Sleep onset occurred after 21 minutes. In all, the study lasted 341 minutes during which 209 minutes of sleep was recorded for a sleep efficiency of 61%. REM occupied 20% and slow wave sleep 20% of total sleep time. There were 47 awakenings and, on average, 48 brief arousals per hour of sleep; 105 per hour in the first portion of the night and 29 per hour during treatment.

Highly irregular respiration was present in the first portion of the study. During the 52 minutes of sleep without CPAP, the total RDI was 91 events per hour, consisting of 76 hypopneas and 4 respiratory effort related arousals. O2 sats fell as low as 83%. End tidal CO2 averaged 56 torr. Greatest elevation was to 61 torr. CPAP was introduced at a pressure of 6cm of H20 and increased in a stepwise fashion to as high as 14 cm of H2O. The prevelance of respiratory evens fell to 3 per hour. Oxygen saturation did not fall below 90% during treatment, but ETCO2 was >50 torr for 89% of the treatment portion of the study. There was no periodic leg movement activity. The EKG showed a sinus rhythm without dysrhythmia.

Interpreation: This study showed a severe degree of disordered breathing that was sustantially relieved with use of nasal CPAP. Hypercapnia was observed throughout the night. The sleep architecture was notable for a marked reduction in brief arousals and the development of good periods of both slow wave and REM sleep during treatment.

DX:
1. Obstructive sleep apnea/hypopnea, severe, resolved with CPAP
2. Hypoventilation during sleep, moderate to severe, persistent.

Recommendation:
1. Nasal CPAP should be continued at home with a setting of 14 cm of H2O.
2. If the patient is subject to morning headache or confusion, treatment with BPAP should be considered to reduce hypercapnia during sleep.

After a couple of pages of tables, this was my CPAP titration chart:
pressure ......... AHI
6 ------------- 4.1 (central apnea, no REM)
8 -------------- 0
10 -------------- 0
12 ------------- 17.8 (central apnea, only time I was in REM)
13 -------------- 0 (no REM)
14 -------------- 3.5 (central apnea, no REM)

What confuses me is why they continued to increase the pressure when my hypopneas completely resolved on 6cm H2O. How did they come to the conclusion that I needed 14 cm of H2O? If my apneas spiked during REM and I only had REM at 12 cm of H2O, how do they know that 14cm of H2O are adequate?

I have no cpap as of yet so no info to report on what happens at home in my own bed. I was told to call and schedule a follow up approximately 30 days after I begin using the CPAP. There was no discussion of morning headaches, confusion, or bpap. The nurse practitioner who reviewed my study pointed out the persistently high CO2 but did not suggest any kind of investigation, treatment, or referral to a pulmonologist.

Any thoughts based on this additional info? Should I push for a bpap vs. a cpap or just try the cpap and see where things go? Because I'm young, disabled, and poor, I feel like my health problems are not always taken seriously (meaning that I'm just expected to "live with it" even when treatment is available).

For example, the recommendations from a sleep study I had three years ago said I had borderline OSA and that I ought to undergo a cpap trial. This information was never shared with me and I never had a cpap trial. I found this out at the sleep study two weeks ago when the nurse practitioner was reviewing my old study and asked why I wasn't currently using a cpap. My night sleep and daytime drowsiness have continously worsened since the last sleep study until I finally begged my doctor for another sleep study referral. I'm trying really hard to make sure I get adequate treatment, but my lack of info makes it difficult for me to successfully advocate for myself.

Thanks for all the help!
Sid

PS. Although I have a disability, I do not have medical condition that would explain the hypoventilation or hypercapnia. I am a wheelchair user due to lower extremity injury and post-operative surgical complications. I am not a smoker and I do not have any type of lung disorder/disease. I do not have any issues with hypoventilation/hypercapnia when I am awake.
10-16-2013 09:05 PM
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Peter_C Offline

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Post: #10
RE: Confusing sleep study results - pressure?
Well, what little I do know tells me one reason for a higher pressure, is to chase after REM sleep.

Also, historically, most people end up needing a higher pressure at home after being on the machine awhile than the study tends to suggest - perhaps this is being taken into consideration? (Guess only)

I also know that they look at more than just AHI numbers. How long between events (meaning hopefully more good sleep), and other stuff like that. That is one point some folks seem to forget, it's not just about the numbers, it's also how do you feel in the mornings? Better, worse, etc? Even - a simple 'do you think your pressure is high enough' comes into play.

At one point my pressure was raised '2' simply because it increased my level of comfort while awake.

About the BI-PAP? Historically, folks have a harder time adjusting to a BI-PAP than to a CPAP, so in the interest of compliance, they are loathe to put someone on a BI-PAP if there is any chance of a CPAP doing the job.

*I* am not a DOCTOR or any type of Health Care Professional. My thoughts/suggestions/ideas are strictly only my opinions.

"Only two defining forces have ever offered to die for you. Jesus Christ and the American Soldier. One died for your Soul, the other for your Freedom."
10-16-2013 10:33 PM
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