Pressure paradox

[Snorkler]

I am using an auto-pap I have been tracking my AHI data. I have set the auto-pap in a range from 7 to 12. The pressure very rarely goes above 9 and when it does the results are worse. Reviewing the last week few week’s data I noticed that as my pressure increases from a minimum of 7 to 9 that the number of apneas increase (from 0.5 to 1.2), while the number of hypopneas decrease (from 3.3 to 0.4) and the overall AHI decreases (from 3.8 to 1.8 ). I have listed the effects of going from a psi of 7 to 9 below:

PSI: 7
AI: 0.5
HI: 3.3
AHI: 3.8

PSI: 8
AI: 1.0
HI: 3.1
AHI: 4.1

PSI: 9
AI: 1.2
HI: 0.4
AHI: 1.6

As pressure goes past 9 the numbers tend to get a little bit worse, so for me the best results are in a range from about 7 to 9.

My question is whether it is more desirable to pursue a lower overall apnea index which produces a somewhat higher hypopnea index (and a higher AHI index), or is it better to achieve a lower overall AHI index (even though this means a higher apnea index)?

By the way, I feel pretty good after a night’s sleep whether the pressure is at 7, 8 or 9. But I want to know if the more experienced people here have any guidance on this matter and whether this type of result is common.

Thanks,

Jeff

[BlackSpinner]

The question is whether the raise in pressure is due to stubborn apneas or vice versa.
Doesn't an apap keep rising until you start breathing again?

So basically you have some apneas that do not respond to the lower pressure and require the pressure to be jacked up until you do while the HI's seem to respond to lower pressures.

[jnk]

Are those the results of running at a straight pressure all night or in a range of pressures?

In general, with a Respironics machine, many consider the goal to be shooting for lower machine-estimated AHI overall. With a ResMed machine, many shoot for lower machine-estimated AI before paying any attention to HI or AHI. At least, that's how I understand it.

[Snorkler]

Are those the results of running at a straight pressure all night or in a range of pressures?

In general, with a Respironics machine, many consider the goal to be shooting for lower machine-estimated AHI overall. With a ResMed machine, many shoot for lower machine-estimated AI before paying any attention to HI or AHI. At least, that's how I understand it.

To answer your question, these are the result of letting the apap run in a range of pressures. Thanks for the answer that with a Respironics, many consider the goal to be shooting for the lower AHI overall. Given that whether the pressure is 7, 8 or 9 my overall AHI is below 5 I am not sure that there is much of a difference.

[john5757]

Are you talking about events per hours? The slight increase of AI with pressure could be central in nature. Looks like pressure of 9 is your sweet spot. Just my opinion not medical.

[Snorkler]

Are you talking about events per hours? The slight increase of AI with pressure could be central in nature. Looks like pressure of 9 is your sweet spot. Just my opinion not medical.

The figures represent average apneas, hypopneas and AHI per hour.

I am not sure about centrals, but according to the reports I have zero "non-responsive" events. I think this means that I have no central apneas reported.

[jnk]

. . . Given that whether the pressure is 7, 8 or 9 my overall AHI is below 5 I am not sure that there is much of a difference.

There is a difference if you FEEL the difference. Some do, some don't. Depends on how sensitive your nervous system is. Many feel that they may as well get AHI as low as possible, just for the principle of the thing and to keep them focused on their therapy. Others would rather stop thinking about it, to settle their own stomach.

Some might suggest that you now try those three pressures without varying pressures in order to see what that does for your numbers. Some get better numbers nightly for treatment using non-varying pressure. That may be worth checking out if you enjoy the data and tweaking thing. Although, if you don't feel a difference either way, no one would fault you for simply being happy with success.

jeff

[Snorkler]

. . . Given that whether the pressure is 7, 8 or 9 my overall AHI is below 5 I am not sure that there is much of a difference.

There is a difference if you FEEL the difference. Some do, some don't. Depends on how sensitive your nervous system is. Many feel that they may as well get AHI as low as possible, just for the principle of the thing and to keep them focused on their therapy. Others would rather stop thinking about it, to settle their own stomach.

Some might suggest that you now try those three pressures without varying pressures in order to see what that does for your numbers. Some get better numbers nightly for treatment using non-varying pressure. That may be worth checking out if you enjoy the data and tweaking thing. Although, if you don't feel a difference either way, no one would fault you for simply being happy with success.

jeff

I do not feel much of a difference when running pressure at 7, 8 or 9. Maybe this is because I am not too sensitive to the differences.

I had a cpap before I got this apap, but it did not have full data capabilities. Maybe I will follow your suggestion at some point to try running the apap in cpap mode (non-varying pressure). But for now, I am just trying to adjust the minimum pressure on the apap in order to imrpove the AHI data.

[KatieW]

My question is whether it is more desirable to pursue a lower overall apnea index which produces a somewhat higher hypopnea index (and a higher AHI index), or is it better to achieve a lower overall AHI index (even though this means a higher apnea index)?

This may be a simplistic way of looking at it, but my choice would be to have a lower AI, since an apnea is when airflow stops for more than 10 seconds. Since oxygen levels, heart rate, and blood pressure can be affected, you want to minimize them as much as possible. The duration of apneas and degree of oxygen desaturation would be an indication of the severity of this.

On the other hand, HI, as measured on a xpap are a partial reduction of air flow. And while this can disturb your sleep, they are not as "dangerous".

The way to measure if oxygen desaturation is occurring is to use a recording pulse oximeter. If you doctor orders one, you might be able to borrow one from your DME for an overnight test. Or you can buy your own--you can do a search to find various models used by forum members. I have the CMS 50E, from SE Medical Supply.

My own experience is that I do better on cpap, and that both my AI and HI went down, once I found the right pressure.

[Snorkler]

Thanks KatieW, I will take your suggestions about the oxyimeter.

By posting here I was hoping to find some suggestions of others and you have provided me with a good point of view.

For now I am not sure whether to set my minimum to 7, 8 or 9. Once I figure this out, then I may try using the apap in cpap mode.

[DreamStalker]

I am using an auto-pap I have been tracking my AHI data. I have set the auto-pap in a range from 7 to 12. The pressure very rarely goes above 9 and when it does the results are worse. Reviewing the last week few week’s data I noticed that as my pressure increases from a minimum of 7 to 9 that the number of apneas increase (from 0.5 to 1.2), while the number of hypopneas decrease (from 3.3 to 0.4) and the overall AHI decreases (from 3.8 to 1.8 ). I have listed the effects of going from a psi of 7 to 9 below:

PSI: 7
AI: 0.5
HI: 3.3
AHI: 3.8

PSI: 8
AI: 1.0
HI: 3.1
AHI: 4.1

PSI: 9
AI: 1.2
HI: 0.4
AHI: 1.6

As pressure goes past 9 the numbers tend to get a little bit worse, so for me the best results are in a range from about 7 to 9.

My question is whether it is more desirable to pursue a lower overall apnea index which produces a somewhat higher hypopnea index (and a higher AHI index), or is it better to achieve a lower overall AHI index (even though this means a higher apnea index)?

By the way, I feel pretty good after a night’s sleep whether the pressure is at 7, 8 or 9. But I want to know if the more experienced people here have any guidance on this matter and whether this type of result is common.

Thanks,

Jeff

If those are data from 3 individual nights, the data is meaningless. If those are long-term averages from several weeks worth of data, you may be sensitive to central or mixed apnea.

It is generally more desirable to maximize O2. Therefore you need to monitor O2 with an oximeter to determine what apnea/hypopnea ratio is best for you.

[Snorkler]

OK, well I changed the pressure on my apap and raised the minimum from 7 to 9. After one week using the apap with the minimum pressure set at 9 my week-long average AHI decreased from an average of around 2.5 down to 1.0. The weekly averages look as follows:

PSI: 9
AI: 0.6
HI: 0.4
AHI: 1.0

So, I am happy to say that I have found a very good pressure. During the past week I had one night with a low AHI of 0.5 while my high was an AHI of 1.8. The 0.5 AHI was the lowest that I have recorded to date.

I have yet to get an oximeter to check O2 levels, but I am feeling great!!!

Thanks for all the help from everyone here

[KatieW]

That's good news. Congratulations.

[mindy]

If those are data from 3 individual nights, the data is meaningless. If those are long-term averages from several weeks worth of data, you may be sensitive to central or mixed apnea.

It is generally more desirable to maximize O2. Therefore you need to monitor O2 with an oximeter to determine what apnea/hypopnea ratio is best for you.

I agree with Dreamstalker based on my own experience. I used a Respironics M-Series auto and for me, it worked better with a single pressure. When I had a range, it would inevitably bump up against the top end no matter what I did. As a result, I did better with a single pressure. Eventually I went with the Sandman Auto which, like it's predecessor the Puritan Bennett auto, has a different algorithm to detect central apneas. Once I get the settings adjusted properly for me, I could use a pressure range again and my AHI dropped lower than it had ever been on the Respironics.

I also got a recording pulse oximeter and use that to periodically verify that my therapy is going well.

This is just what worked for me ... I'm not in any way saying that I think others should do this. I do think that if results of using a pressure range aren't giving you adequate therapy, you might want to consider trying a single pressure.

Mindy