Central Apnea Events & Pressure Settings

[WakeUpTime]

[attachment=778]I think it's been said here that the goal is to get just enough pressure to bring the Obstructive Apneas down to below 5. It's a real struggle (torture in fact) to reduce the Central Apneas.

Last night I bumped the pressure by 0.5 (IPAP 12, EPAP @8) and CA events rocketed to 14 from the usual 6 or so. OA events went down to 2 from the usual 3, but it sure made for a terrible sleep and a rotten next day.

For those not on an BPAP SV machine, I'm curious if you experienced the same things in the beginning -- Central Events that lingered. Did they eventually go away in time after 6 months, a year, never?

I was always told my persistent CA of 5-6 would probably eventually go away. After 3-4 months, not only has that not happened, there have been many times when it's gone up considerably. Perhaps it's better to aim for lower pressures and hope that the OA events reduce on there own over time; otherwise, aggressive pressure fighting really helps Mr. Centrals to explode.

I do have another curiosity. It seems that most people with Auto machines park themselves at a pressure point. I tried using Auto mode on my BiPAP machine and it made for really bad sleep nights. My read on it was that all that changing pressure throughout the night (let's try this, opps, ok let's try that) caused a lot of discomfort.

[c0reDump]

I think it's been said here that the goal is to get just enough pressure to bring the Obstructive Apneas down to below 5. It's a real struggle (torture in fact) to reduce the Central Apneas.

I think the goal to is get the total Apneas (Central and Obstructive) along with Hypopneas -- all these make up the Apnea/Hypopnea Index (AHI) -- down to 5.0 or below. This means, on average, a total of 5 CA/OA/H per hour or less.

When I first started therapy about 2 months ago, my AHI was predominately made up of CAs (according to my SleepyHead data) -- more recent nights are showing that I'm having about 1 CAs for every 4-5 OAs. My highest AHI so far has been 4.2 -- so the ratio of CAs to OAs isn't much of a concern for me since the total AHI is still below 5.0

I'm no expert on the VPAP/BiPAP machines, but if you have CAs, you are using the right machine as far as I know. Hopefully someone else can chime in to double check your settings.

[robysue]

I think it's been said here that the goal is to get just enough pressure to bring the Obstructive Apneas down to below 5. It's a real struggle (torture in fact) to reduce the Central Apneas.

For some people, it is indeed a real struggle to find a pressure setting on a CPAP or pressure settings on an ordinary bi-level PAP (a BiPAP or VPAP) that is high enough to keep the obstructive events under control while being low enough to not trigger a clinically significant number of CAs. These folks are eventually diagnosed with CompSA and in many cases, they are eventually moved to an ASV machine.

Last night I bumped the pressure by 0.5 (IPAP 12, EPAP @8) and CA events rocketed to 14 from the usual 6 or so. OA events went down to 2 from the usual 3, but it sure made for a terrible sleep and a rotten next day.

Are you talking about the actual number of CAs and OAs for the entire night or are you talking about the CAI and OAI---the average number of CAs and OAs in each hour of sleep?

If you typically have about 3 OAs during the course of the whole night, then your OAI is very low and there' no reason to increase the pressures. To be very clear: If you typically have 3 OAs, 0 Hs, and 6 CAs during 7 hours of sleeping with the machine, then your AHI = 9/7 = 1.29, which is plenty low enough to NOT worry about and there is NO NEED to increase the pressure settings to try to eliminate the last few obstructive events, particularly if the pressure increase also increases the number of centrals that are scored.

But if you typically have around 3 OAs per hour of run time and 6 CAs per hour of run time, then your overall AHI is 11 and during the course of a seven hour night, you will have about 77 events, 21 of which are OAs and 42 of which are CAs. In this case, you meet the guidelines that warrant further investigation to determine whether you have CompSA. The guidelines are for considering whether CompSA might be an issue include all of the following: (1) A treated AHI > 5.0; (2) a treated CAI > 5.0; and (3) CAs make up at least 50% of the events that occur during treatment.

For those not on an BPAP SV machine, I'm curious if you experienced the same things in the beginning -- Central Events that lingered. Did they eventually go away in time after 6 months, a year, never?

To wind up on the BiPAP Auto SV Advanced (ASV) machine, a person has to have had some serious problems with CAs that remained for some time after starting CPAP/APAP/BiPAP. Insurance companies won't pay for these machines unless it's been demonstrated that the CAs don't resolve themselves after a few weeks or months of CPAP/APAP/BiPAP therapy.

And the CA events on CPAP/APAP/BiPAP have to be clinically significant in number before a person will be switched to an ASV machine. That typically means that the CAI---the average number of centrals per hour has to remain above 5.0 and they have to make up at least 50% of the events that are scored while on CPAP/APAP/BiPAP therapy. But if you are having 5-6 CAs per NIGHT, the CAI will not be any where near high enough for a switch to an ASV machine. And it's not clear from your writing whether you are dealing with 5-6 CAs per NIGHT or 5-6 CAs per HOUR.

I was always told my persistent CA of 5-6 would probably eventually go away. After 3-4 months, not only has that not happened, there have been many times when it's gone up considerably. Perhaps it's better to aim for lower pressures and hope that the OA events reduce on there own over time; otherwise, aggressive pressure fighting really helps Mr. Centrals to explode.

Again, are we talking about 5-6 centrals being scored for the entire night or are we talking about enough CAs so that the average number of CAs per hour is 5-6? It makes a huge difference, and it is not clear from your writing what you are talking about.

I do have another curiosity. It seems that most people with Auto machines park themselves at a pressure point. I tried using Auto mode on my BiPAP machine and it made for really bad sleep nights. My read on it was that all that changing pressure throughout the night (let's try this, opps, ok let's try that) caused a lot of discomfort.

Not everyone does well on Auto PAP or Auto bi-level. The changing pressures do in fact disturb many PAPers sleep and they find that sleep is easier when using fixed pressure mode. If you don't like Auto mode on your BiPAP, then use it in straight BiPAP mode with a fixed IPAP and fixed EPAP that do not vary over the course of the night.

[zonk]

For those not on an BPAP SV machine, I'm curious if you experienced the same things in the beginning -- Central Events that lingered. Did they eventually go away in time after 6 months, a year, never?

I don,t recall having central apnea during the sleep study or on PAP. My autoset increase pressure in response to snoring and flow limitation which are precursors of obstructive apnea but not central apnea. Treating obstructive apnea and at the same time not inducing central apnea or causing pressure runaway ... hitting two birds in one stone

[WakeUpTime]

These folks are eventually diagnosed with CompSA and in many cases, they are eventually moved to an ASV machine.

I'm just wondering how many more months to hang in there and wait to see if the CA events go down from the persistent 5-6 (or higher) per hour. My daily data continues to show the CA's but the sleep dr. is sticking to the data from the initial sleep study.

But if you typically have around 3 OAs per hour ...you meet the guidelines that warrant further investigation to determine whether you have CompSA. The guidelines are for considering whether CompSA might be an issue include all of the following: (1) A treated AHI > 5.0; (2) a treated CAI > 5.0; and (3) CAs make up at least 50% of the events that occur during treatment.

Yes, they are PER HOUR and persistent little buggers. I'm definitely YES to #1,2 & 3. Again sleep dr said they're always present in the introductory CPAP stage and fade away over time. (Years?)

Are you talking about the actual number of CAs and OAs for the entire night or are you talking about the CAI and OAI---the average number of CAs and OAs in each hour of sleep?

Yes, the CAI and OAI (per-hour).

To wind up on the BiPAP Auto SV Advanced (ASV) machine, a person has to have had some serious problems with CAs that remained for some time after starting CPAP/APAP/BiPAP. Insurance companies won't pay for these machines unless it's been demonstrated that the CAs don't resolve themselves after a few weeks or months of CPAP/APAP/BiPAP therapy.

And the CA events on CPAP/APAP/BiPAP have to be clinically significant in number before a person will be switched to an ASV machine. That typically means that the CAI---the average number of centrals per hour has to remain above 5.0 and they have to make up at least 50% of the events that are scored while on CPAP/APAP/BiPAP therapy.

My lab CA's (per hour) weren't significant but right on the line of about 5 per hour. So, I was never pushed into an SV machine. But outside of the lab, I'm at 5-6 most nights (per hour) with the occasional nights at 8-10 (perhaps every 4th night).

I'm actually not pushing for any kind of CA certification for insurance purposes, since I don't have additional health insurance. I'm willing to pay for any technology that might solve the sleep mess because I'm definitely not there yet -- although I'm grateful for the huge reduction in OA events and getting O2 to my brain each night.

Not everyone does well on Auto PAP or Auto bi-level. The changing pressures do in fact disturb many PAPers sleep and they find that sleep is easier when using fixed pressure mode. If you don't like Auto mode on your BiPAP, then use it in straight BiPAP mode with a fixed IPAP and fixed EPAP that do not vary over the course of the night.

If I do go into an SV machine eventually, I understand those occasional pressure blasts (that blast a person out of an CA event) can also (ironically) disturb sleep.

[robysue]

These folks are eventually diagnosed with CompSA and in many cases, they are eventually moved to an ASV machine.

I'm just wondering how many more months to hang in there and wait to see if the CA events go down from the persistent 5-6 (or higher) per hour. My daily data continues to show the CA's but the sleep dr. is sticking to the data from the initial sleep study.

Thanks for clarifying which numbers you're talking about. The average number of centrals per hour is call the Central Apnea Index and is abbreviate CAI. Likewise the OAI is the Obstructive Apnea Index and the AHI is the total Apnea Hypopnea Index, and they represent the average number of obstructive apneas per hour and the average number of (apneas + hypopneas) per hour. So you are talking about the CAI and OAI.

So first, in light of that let me review to make sure I really understand:

At IPAP = 11.5 and EPAP = 7.5, the OAI is usually about 3 and the CAI is usually about 6 and the total AHI is usally about 9 (or higher if the HI is not zero)

At IPAP = 12 and EPAP = 8, the OAI decreases to 2, but the CAI zooms up to 14 and the total AHI is thus about 16 (or higher if the HI is not zero).

And you've been at this for about 3 months. And the sleep doc won't look at the data your machine is recording.

Have I summarized things correctly?

So right now the problem is: The current BiPAP and its settings leave you with too many residual events, (the AHI > 5 and the CAI > 5), and the majority of the residual events are centrals. But the doc won't budge on considering the need for either an official pressure adjustment or switch to an ASV machine. And the doc keeps telling you some version of "Give it more time."

Here are my thoughts and ideas.

1) There's no point in increasing the pressure since CAs are not treated by pressure increases in IPAP or EPAP. Indeed, as you've seen, additional (full time) pressure can make the CAs worse, not better.

2) It's worth considering what happens if you DECREASE the pressure settings just a smidge: What happens if you use IPAP = 11 and EPAP = 7?? The number of obstructive events (OAs and Hs) is likely to increase, but the number of CAs may go down. The question is what happens to the AHI? If the total AHI goes down enough with the pressure decrease, then trading a few more obstructive events for far fewer central events just might be worth it.

3) I'm assuming that you are using your PR System One BiPAP Auto in fixed BiPAP mode rather than Auto mode. Is that correct? If so, it may be worth switching to BiPAP Auto mode. That may let you use less pressure on average, while still allowing the machine to increase the pressure as needed to treat the obstructive events. If you go this route, I'd suggest using max IPAP = 11.5 and min PS = 4 as starting "caps" since you already know that centrals are a problem when the pressure gets up around this level. The question is what should min EPAP be set at? That's a question that you might be able to get the doc to answer. But if you are really up to experimenting without the doc's official permission, you might try starting out at min EPAP = 4 (the minimum possible EPAP) and see if you're comfortable breathing with the pressure that low. Track what happens for a week or so, and then maybe see if there's some kind of correlation of pressure settings and when the CAs start to emerge. And also track just how much pressure the machine wants to use to keep the obstructive events under control. If your median IPAP = 11.0 or 11.5 and your median EPAP = 7.0 or 7.5, you'll know there's not much room for decreasing the pressures from the point of view of managing the obstructive part of your problem.

4) As for talking to the doctor. I've not had much luck here: I'm on Sleep Doc #4. Doc #1 fired me, Doc #2 and I fired each other at the same meeting, and I fired Doc #3. I get along with Doc #4, but part of that is that Doc #4 does use a patient portal system, and hence I can write emails which somehow provide for better communication in my case than the standard 5-15 minute face-to-face appointments ever did. That said, here's the standard advice given to people who feel as though their doc is not listening:

• Come with a short written list of questions you need answered. Better yet, try to drop a copy of list off a day or two before your appointment and tell the receptionist that you want to make sure the doc gets the list of questions.
  
• Provide a full Encore Viewer or Encore Pro report of the data from your machine along with the questions. I suggest Encore because it is the official software. Most docs have not heard of SleepyHead and even if they have, most are not going to trust SH since it's not official.
  
• Be sure to address this question from the doc: How are you feeling now that you're using BiPAP? If you are still feeling lousy, be honest. Keep your answer focused on subjective quality of life language instead of the data. As long as you say you are feeling "ok" or "sort of ok" or "not too bad", the doc is going to assume that things are "ok" and will likely improve with time and not look at the data. If you are honest about just how rotten you feel, you have a better chance of getting the doc to look at the data and notice there are a lot of centrals. But if you answer How do you feel? by talking about the machine's data, the doc probably won't hear you.
  
• It's worth writing down and rehearsing your answer to How do you feel? so that the answer focuses in on getting the point across to the doc that you are feeling lousy in spite of using the machine AND that you are not merely reacting to seeing "bad" data in the morning. The answer to How do you feel? should NOT contain the phrase "central apneas" in it.
  
• It's also worth preparing your response to the inevitable suggestion of You just need to give it more time. This is were bringing up the data may be appropriate. You need to politely point out that you HAVE given it plenty of time and things are not getting better. You need to point out that the AHI is still running above 5.0 most days and that the (vast) majority of your events are centrals. And that you need to know just how much "more time" the doc thinks you need before something starts to turn around. And if the titration study showed problems with centrals, this is where you point that out too.

Best of luck in finding a decent enough sweet spot between enough pressure to manage the OSA and not enough pressure to trigger too many problems with the CSA

[justMongo]

I don,t recall having central apnea during the sleep study or on PAP. My autoset increase pressure in response to snoring and flow limitation which are precursors of obstructive apnea but not central apnea. Treating obstructive apnea and at the same time not inducing central apnea or causing pressure runaway ... hitting two birds in one stone

I hate to hijack this thread... no I don't.

I saw some centrals at higher pressures during my initial titration.

I'm using my machine 7.5 hours or more per night; and it reports an AHI under 3. They are scored as obstructive and not in tight clusters. Viewing the fine data, I see periods of snoring and flow limitation. I feel my sleep quality is rather good. I'm wondering if I should try some small deltas with the pressure to try to reduce snore and flow limitation when my AHI is good; and I feel OK as far as sleep is concerned.

[robysue]

I hate to hijack this thread... no I don't.

I saw some centrals at higher pressures during my initial titration.

I'm using my machine 7.5 hours or more per night; and it reports an AHI under 3. They are scored as obstructive and not in tight clusters. Viewing the fine data, I see periods of snoring and flow limitation. I feel my sleep quality is rather good. I'm wondering if I should try some small deltas with the pressure to try to reduce snore and flow limitation when my AHI is good; and I feel OK as far as sleep is concerned.

If it ain't broke, don't fix it. Seriously.

If you are feeling fine---if you wake up feeling rested and refreshed; and you have enough energy and alertness to get through your days---then there's no point in trying to make the data look "better". And there's always the risk that even a small change in pressure will create problems with aerophagia, leaks, and general restlessness, along with the potential of an increase in central events that exceeds the decrease in obstructive events.

[PaytonA]

You beat me to it, Robysue.

Mongo,
Remember the old engineering adage:

If it ain't broke, don't fix it!

PaytonA

[justMongo]

You beat me to it, Robysue.

Mongo,
Remember the old engineering adage:

If it ain't broke, don't fix it!

PaytonA

Where I worked, our adage and motto was:
"There's never enough time to do it right... but, there's always enough time to do it over."