Need help understanding Titration Data

Hi

I have been reading all of the recent forum posts related to CPAP's, Auto CPAP's, sleep studies, MD orders, and DME profit trying to understand it all and I see I have a lot to learn.

Tonight I reviewed my own diagnostic sleep study and treatment titration sleep study data my doctor used to determine diagnosis and treatment.

My results do not make sense to me and I am wondering what you guys think of it all.

My sleep study AHI is 23.9.
My titration data study shows a total AHI ranging from 4 to 56.3.
Why would my AHI go so high during the sleep study???

Thank you

Would need to see the entire report to know for sure but maybe the higher AHI number relates to a time frame where lower pressures (that were not effective) were used that extrapolated out to a higher per hour average and the lower AHI was when the pressure was increased to the level it was able to prevent the apneas.

Hi Pugsy,
Thank you very much.
I would appreciate your reviewing the report with me. My doctor did not say much about it.
What is the best way for me to get the report to you?
Kathy

You can either block out any personal information on the report and scan it and take a screen shot and treat it like any other screen image where we post our reports.
viewtopic/t103468/Need-help-with-screen-shots.html

Or you can send it to me as an attachment to my private email. We can't do attachments with the forum messaging system.
I will send you a PM in a little bit telling you my private email addy. Doesn't matter if I get it that was as a pdf or a screen shot image as long as I can read it.
I won't post it unless you give the okay.
No rush to send it to me though....I will be leaving the house shortly and won't be able to get to it until later this afternoon/evening.

Sonnyboy wrote: My sleep study AHI is 23.9.
My titration data study shows a total AHI ranging from 4 to 56.3.
Why would my AHI go so high during the sleep study???

The short answer on why you might have an AHI = 56.3 for a small part of the titration data is that the titration AHI's are often computed for each pressure that is tried, and sometimes that means they are computed over very short time. To give you an example:

Let's suppose you were at 7cm for a grand total of 5 minutes. Note that 5 minutes = 1/12 hour = 0.083 hours. If you had 5 events during those 5 minutes (perhaps because you were in REM and 7 cm is not enough to control your apnea during REM), your AHI for 7cm of pressure would be 5/0.083 = 60.2. Obviously the tech would not leave you at 7cm for very long if you had a cluster of 5 events, but the "5 events at 7cm" pressure still has to be recorded, and it gets recorded as an AHI = 60.2 at 7cm.

The goal of the titration is to find a pressure where the AHI = 0 or very close to 0 for an extended period of time that (hopefully) includes some REM sleep and some supine sleep. The AHI's for (much) lower pressures are not particularly relevant.

Hi Pugsy and Robysue,

Robysue-I see what you are saying but am not able to correlate this information with my report. My brain is missing a link here.

I don't mind posting the study for feedback if it helps anyone else learn too.

Do I post the screen shot through Imgur just like I posted the daily graphs?

One really dumb thing I did is that I was taking all the right vitamins prior to the polysomnogram report and titration studies based on earlier lab work and not knowing I had severe PLMD and then when I got the PLMD diagnosis and Neurontin was prescribed I stressed out and for some reason stopped taking the vitamins not understanding I needed them for the PLMD.
So thanks to reading the forum I am back on them.

yes...just take a screen shot of the report and treat it like you did the screen shots of your machine software reports.
As long as we can read it..that's all that matters.

Hi Pugsy,

Here is the Cpap Titration Report.

I am wondering about the high AHI's in the table on page 3 and also why they stopped testing at the 4.5 AHI.

Thank you,

The difference in the AHI at the lower pressure could easily be related to sleep position and the lower pressure tried at that time with a little bit of REM thrown in. I wouldn't worry about it. From the different sleeping positions reported it appears that your OSA is likely worse when you are on your back which is actually very common. I can't see the graphs following the page 3 pressure summary but I don't know that it is all that important to see at this point.
The reason the AHI is so during that almost 2 hours at 6 cm test was very likely related to sleeping position making the OSA worse and the pressure of 6 not being about to do much to prevent the airway collapse.

Why did they stop at 4.5 AHI and not try to improve on it? Technically the AHI was below 5 which is acceptable and they may have simply run out of time to test further.
If your oxygen levels were good at that 9 cm pressure and the AHI is below 5.0 perhaps that is good enough for whatever criteria that lab or doctor uses.

Thank you Pugsy,
I appreciate your input.

Pugsy wrote:The reason the AHI is so during that almost 2 hours at 6 cm test was very likely related to sleeping position making the OSA worse and the pressure of 6 not being about to do much to prevent the airway collapse.

Pugsy is absolutely correct. Your study shows that you are particularly susceptible to Hypopnea events when laying on your back and your left side. At least you were that night. The majority were recorded while you were on your left side (this is probably because that's where you spent most of the evening).

During the 110 minutes (about 2hrs) that you were at a pressure of 6, as you know, you had an AHI of 56.3. This is because you recorded the majority of your Hypopnea events during that phase of the titration. Of the 88 total Hypopneas, 51 occurred while you were at a pressure of 6. What also contributed to the AHI being so high at that time is the fact that you only slept for 55% of those 110 minutes. This reduces the time used to calculate the AHI. Less time + increased events= higher AHI.

It looks to me like, for whatever reason, you were going through some rough patches and struggling a little from about 1:30am to about 3:30am. I wouldn't worry too much about it. It's a process and everything gets recorded step by step. Every pressure change has it's own AHI. I would focus more on the end result and it seems they did a pretty good job.

On a side note, this is a great example why you should never change your pressure. 9cmH20 = AHI-4.5 , 6cmH20 = AHI-56.3. Just sayin.

I know, I know.........APAP

Sonnyboy wrote:Hi

I have been reading all of the recent forum posts related to CPAP's, Auto CPAP's, sleep studies, MD orders, and DME profit trying to understand it all and I see I have a lot to learn.

Tonight I reviewed my own diagnostic sleep study and treatment titration sleep study data my doctor used to determine diagnosis and treatment.

My results do not make sense to me and I am wondering what you guys think of it all.

My sleep study AHI is 23.9.
My titration data study shows a total AHI ranging from 4 to 56.3.
Why would my AHI go so high during the sleep study???

Thank you

Welcome to the board. I'm glad Pugsy chimed in to help you understand your question. Good luck with your pap therapy

kcodeblue wrote:I know, I know.........APAP

Sometimes it does come in handy for some folks.
I am one of those folks. My REM events must be on steroids and of course my OSA is about 5 times worse in REM and my pressure pushed 20 when I was using the apap and during probably REM sleep. Rest of the night somewhere between 10 - 12.
I did finally get my docs blessing to use apap once I showed proof of such a wide difference in pressure needs.
Supine sleeping didn't do much though. I built a wall so I would absolutely not be able to get on my back so that I could see if I still had higher pressure needs in probable REM sleep and yep....same pattern.

So I decided APAP machine and sleep in whatever position I wanted and let the machine sort it out and deal with it.

The sleep titration study got it wrong too. It wasn't the idiot tech (idiot for other reasons though) because I only got about 6 minutes of REM and barely got enough sleep to get the titration done anyway. It's no wonder the RX pressure was insufficient.
I had bought my own machine out of pocket anyway...found one local on craigslist that cost about what my copay and deductible would have cost me. I still use a DME for masks though. He still tries to sell me a machine too. We just laugh about it.