Increased pressure = increased AHI

[Elle]

Since my pressure was increased from 15 to 16 this week my AHI has gone up. I am usually under 1 and am now over 2. I know that is still great results but it is interesting to me that this happened.

[BigTex]

Why was the pressure increased if your AHI was under 1?

[Elle]

My data showed me hovering around my top pressure so the RT thought it would go even higher if allowed.

[kaiasgram]

You should be hearing from pugsy and robysue any minute now!

[LSAT]

I agree with the RT. One night is not considered a trend. Watch it over a week or two Going from 1 to 2 could mean you held your breath when you rolled over during the night.

[kaiasgram]

I do not understand the RT's recommendation to increase your max pressure. Just because your max pressure could go higher doesn't mean it needs to -- and from what you're reporting with an AHI <1, it doesn't sound like you needed a pressure increase. Was there an additional factor involved in the decision to go higher? Were you reporting problems with your sleep or something?

My pressure is almost always hovering around my max, yet I have been setting the pressure a little lower every few nights in an effort to relieve my severe aerophagia and other cpap-related discomforts. I look at my sleep data every morning to be sure my AHI is not increasing. It is not! In fact over my first three weeks of using APAP I have reduced my max pressure from 10 down to 8.2. And every night I ride along at the max setting, yet my AHI is fine. In fact last night I had my first night of zero events while asleep (and just a couple of clear airway events in the early a.m. while mostly awake and restless). AHI = .23 last night if I count those two a.m. events, and AHI = ZERO if I don't count that awake-and-restless period, best night ever for me in terms of the numbers.

So I don't see the fact that you're "running on high" all the time as a compelling reason to push your max pressure up unless your apneas are increasing, which you say they have not been. But I'm still a newbie and I know our resident experts will weigh in on this for you.

[Elle]

It's frustrating to know exactly what to do. I haven't been sleeping as well but have no idea if it is just one of those sleep phases everyone goes through (cpap user or not) or whether it is the result of high pressure. The RT insists it won't go any higher than it needs to. I have had a night with one event and my usual is very few events so to see all of these events made me sigh in frustration. Maybe I need to tighten my mask up now with the higher pressure. I think my leak rate may have increased a tiny bit according to data but I certainly have not felt any leaks.

Nice to have a place to vent here. My struggles are minimal in comparison to some. I'm not looking for perfection but get curious when things don't add up the way I think they should.

Thanks for the replies.

[kaiasgram]

Elle, I hear your frustration. How long have you been on cpap?

I'm still new at all this but I have not yet heard of increasing a patient's max pressure without there being some evidence of the need to do so. I also have not yet heard of cpap therapy doing anything other than controlling the apneas -- in other words, I have never heard of pressure increases helping someone's subjective experience of worse sleep -- again, unless the AHI is also worsening.

But I'm sure I still have more to learn and I'm sure the experts on this forum will have more wisdom about this. My numbers are looking very good too, AHI's are usually <1, but I am far from sleeping well. However, you'd be hard pressed to convince me that raising my pressure back up would improve my quality of sleep. We'll see what others have to say about this.

[LSAT]

I do not understand the RT's recommendation to increase your max pressure. Just because your max pressure could go higher doesn't mean it needs to -- and from what you're reporting with an AHI <1, it doesn't sound like you needed a pressure increase. Was there an additional factor involved in the decision to go higher? Were you reporting problems with your sleep or something?

My pressure is almost always hovering around my max, yet I have been setting the pressure a little lower every few nights in an effort to relieve my severe aerophagia and other cpap-related discomforts. I look at my sleep data every morning to be sure my AHI is not increasing. It is not! In fact over my first three weeks of using APAP I have reduced my max pressure from 10 down to 8.2. And every night I ride along at the max setting, yet my AHI is fine. In fact last night I had my first night of zero events while asleep (and just a couple of clear airway events in the early a.m. while mostly awake and restless). AHI = .23 last night if I count those two a.m. events, and AHI = ZERO if I don't count that awake-and-restless period, best night ever for me in terms of the numbers.

So I don't see the fact that you're "running on high" all the time as a compelling reason to push your max pressure up unless your apneas are increasing, which you say they have not been. But I'm still a newbie and I know our resident experts will weigh in on this for you.

Kaiasgram......Even if her max pressure was set at the top of the scale...20....it wouldn't matter. The CPAP will only go high enough to stop an apnea. The OP has said that..." My data showed me hovering around my top pressure". If her pressure is reaching that level, it may want to go higher to stop an apnea...but can't. The RT was right. "The pressure will not go higher than it needs to..."

[DreamStalker]

I do not understand the RT's recommendation to increase your max pressure. Just because your max pressure could go higher doesn't mean it needs to -- and from what you're reporting with an AHI <1, it doesn't sound like you needed a pressure increase. Was there an additional factor involved in the decision to go higher? Were you reporting problems with your sleep or something?

My pressure is almost always hovering around my max, yet I have been setting the pressure a little lower every few nights in an effort to relieve my severe aerophagia and other cpap-related discomforts. I look at my sleep data every morning to be sure my AHI is not increasing. It is not! In fact over my first three weeks of using APAP I have reduced my max pressure from 10 down to 8.2. And every night I ride along at the max setting, yet my AHI is fine. In fact last night I had my first night of zero events while asleep (and just a couple of clear airway events in the early a.m. while mostly awake and restless). AHI = .23 last night if I count those two a.m. events, and AHI = ZERO if I don't count that awake-and-restless period, best night ever for me in terms of the numbers.

So I don't see the fact that you're "running on high" all the time as a compelling reason to push your max pressure up unless your apneas are increasing, which you say they have not been. But I'm still a newbie and I know our resident experts will weigh in on this for you.

Kaiasgram......Even if her max pressure was set at the top of the scale...20....it wouldn't matter. The CPAP will only go high enough to stop an apnea. The OP has said that..." My data showed me hovering around my top pressure". If her pressure is reaching that level, it may want to go higher to stop an apnea...but can't. The RT was right. "The pressure will not go higher than it needs to..."

Unless she has central or leaks. I agree though, go with RT settings for a week or two and then re-evaluate. Keep leaks under control or AHI values are meaningless.

[kaiasgram]

Gosh this stuff is complex and overwhelming -- and as the OP says, frustrating! DreamStalker, are you saying that the pressure can indeed go higher than it needs to if one is having clear airway events and leaks?

This is a screenshot of my pressure settings and changes since I started on June 8. I would toss out one anomalous night during the ten days that my max was set to 8.6, I had a lot of trouble sleeping and had a bunch of centrals and leaks which shot my AHI for that night up to 6.5, extremely high for me. The revised AHI average for that ten days if I toss the anomalous night would be .62.

I know three weeks on cpap is not a lot to discern trends with, but for what it's worth, my AHI seems to be looking a littlebetter as I've adjust the max pressure down. I should also clarify that virtually all of my events are clear airway events -- I think I've had only two or three obstructives during this entire three week period. So if I'm understanding DS, could my situation be that my pressure really was going higher than it needed to because it was chasing CA's in vain?

[pats]

Kaiasgram......Even if her max pressure was set at the top of the scale...20....it wouldn't matter. The CPAP will only go high enough to stop an apnea. The OP has said that..." My data showed me hovering around my top pressure". If her pressure is reaching that level, it may want to go higher to stop an apnea...but can't. The RT was right. "The pressure will not go higher than it needs to..."

If that reasoning were valid, APAPs would not need any option to enter a maximum pressure.

My APAP often reaches its upper pressure, and would presumably go higher if my prescription allowed it to. On the other hand, it is working beautifully. My AHI is consistently under 2, often under 1, and rarely includes any obstructive apnea events.

[Pugsy]

could my situation be that my pressure really was going higher than it needed to because it was chasing CA's in vain?

Your machine will NOT chase centrals. It won't increase pressures in response to centrals. By specific programming the APAPs won't respond to a central event at all.
Now you might have a flow limitation or a snore around the same time as a "central" and those will cause the machine to respond with a pressure increase because they are obstructive event precursors.

If you didn't have the aerophagia problem...we wouldn't be trying to limit your maximum.
The machine won't go where it doesn't think it has a reason to go.
In your situation though..the least little bit of increased pressure likely in response to some flow limitations that don't make criteria for a full grown up obstructive event...is apt to cause you some aerophagia problems. So for you we suggest limiting the maximum in an effort to reduce the aerophagia symptoms and no other reason. The aerophagia is much harder on you than a few maybe flow limitations or snores.

[kaiasgram]

Your machine will NOT chase centrals. It won't increase pressures in response to centrals. By specific programming the APAPs won't respond to a central event at all.
Now you might have a flow limitation or a snore around the same time as a "central" and those will cause the machine to respond with a pressure increase because they are obstructive event precursors.

If you didn't have the aerophagia problem...we wouldn't be trying to limit your maximum.
The machine won't go where it doesn't think it has a reason to go.
In your situation though..the least little bit of increased pressure likely in response to some flow limitations that don't make criteria for a full grown up obstructive event...is apt to cause you some aerophagia problems. So for you we suggest limiting the maximum in an effort to reduce the aerophagia symptoms and no other reason. The aerophagia is much harder on you than a few maybe flow limitations or snores.

Thanks for watching out for me pugsy. Lowering the max has definitely helped with the aerophagia -- I still have it, but I'm starting to sleep through it a little better now. And from what you're saying, raising the pressure would not do anything to stop the "centrals." Correct?

I plan to leave my max pressure where it is for the forseeable future, but here's the deal: Even though my aerophagia is getting better AND my AHI is consistently <1 AND my leaks have improved markedly since I started lining my chinstrap, AND I have way fewer memories of wakeups or struggles once I've fallen asleep, I continue to wake up in the morning feeling like I've been doing battle all night -- headache, having had dreams of strife and struggle, groggy, feels like my heart's been hard at work, and don't feel refreshed at all. In the morning it feels exactly like it felt when my apnea was not being treated at all (except now I have aerophagia too!). So my question is, is there any research that you know of that suggests that raising the max pressure can improve sleep quality beyond controlling the obstructive apneas? I've never heard of xPAP doing more than controlling apnea events, but I was just wondering. Once your obstructives are eliminated is there any potential benefit to increasing max pressure?

[robysue]

Since my pressure was increased from 15 to 16 this week my AHI has gone up. I am usually under 1 and am now over 2. I know that is still great results but it is interesting to me that this happened.

Elle,

Without seeing the data, we're all working blind here. Could you post the data from a typical night when your max was 15cm and another from when your max was 16cm?

Since your AHI < 1.0 with your max set to 15cm, but your "data showed me hovering around my top pressure so the RT thought it would go even higher if allowed", it seems clear to me that apneas and hypopneas were NOT what was leading to you maxing out at 15 for long periods of time during the night. And in this case it's not immediately clear why you might need more pressure. But----if your exceptionally low AHI was consistently caused by one cluster of, say 4 to 7 events all occurring in a very short (say 10 minute period), then that could trigger you "hovering at 15cm" during the one "bad" cluster of events. And you might indeed need more pressure to bust up that remaining cluster of events each night.

In the first case (you're hovering at 15cm much of the night with no apneas or hypopneas in sight), the question becomes: What's driving the increase in pressure and why do you stay there? Since you are using an S9 Autoset, the question becomes: How's the snore graph? And how is the flow limitation graph?

In the second case (you're hovering at 15cm during ONE or TWO clusters of multiple events), then the question becomes: How many events in how much time? And how severe are the events?

As to why you saw an increased AHI when your max was increased to 16cm, the questions are: Are there clusters of events at 16cm? Are there a slew of centrals present when the pressure is near 16cm that were not there when the max pressure was 15cm?

And to answer whether your max should be 15cm or 16cm, I'd say that answer should be based on your answer to the all important question: Do you feel better or worse or about the same when your max pressure is set to 16cm?