CPAP versus AutoPAP: are there really advantages to each?

[JerryL]

CPAP machines deliver constant pressure. AutoPAP machines -- a.k.a. APAP machines -- adjust the pressure depending on your needs.

I know that AutoPAP machines cost more, and therefore some doctors and insurance companies might prefer CPAP. But are there any actual medical reasons to prefer CPAP? Or is AutoPAP always better?

This AutoPAP article gives the arguments on each side -- but upon careful reading, it doesn't seem to contain any substantive pro-CPAP arguments, other than the fact that CPAP machines are cheaper, and that some AutoPAP machines may be too slow in finding the right pressure. It has tons of strong pro-AutoPAP arguments: my ideal pressure may change during the night (could it vary depending on my sleep position?), it might change over time as I acclimate to PAP, it might change over time as I get older or my weight changes.

It seems that everyone on this forum agrees that a machine that produces sleep data each night is better than one that doesn't. That's not the issue I'm wondering about here. I'm wondering: Assuming my doctor is willing to prescribe a CPAP machine that provides good data, should I try to persuade him to instead prescribe an AutoPAP machine?

[BTS]

Depends really what kinda Apnea you have.. I have Complex Apnea and for insurance reasons had to start with CPAP and it was recomended that I did not use APAP due to it causing more Centrals in Auto mode.. Also APAP wasn't recomended with having asthma and COPD..

APAP for most with OSA is the best choice IMO... Having it changing pressure throughout the night as needed, adjusting to an optimal setting based on the chosen range..

[Pugsy]

There are times when having auto adjusting mode might come in handy.

Example...if someone has widely varying pressure needs during the night for some reason or other.
Sometimes it might be supine sleeping or sometimes it might be REM stage sleep...both which it is fairly common for some people to experience a rather wide difference in pressure needs.

I will use myself for example ....my OSA is worse in REM sleep. Like 5 times worse in REM sleep than in non REM sleep.
On my back didn't seem to make a difference when compared to side sleeping but in REM my OSA is much worse and in REM sleep I might need 18 cm pressure to prevent the airway from collapsing and other sleep stages maybe 8 cm does a great job.
REM sleep usually is about 20% of our sleep time....
So if I were to use a fixed cpap machine I would have to use 18 cm all night long just to cover that 20% of the night I was in REM and needed the much higher pressures.
It's doable...that 18 cm all night long but it's a lot of pressure and not very comfortable and it's just a whole lot easier to use lower pressures the other 80% of the night and have the machine only go higher when needed.

It's a lot more comfortable using 8 cm for 80% of the night and letting the machine sort out the REM pressure needs for the other 20% of the night.
Now not everyone will experience such a wide variation in pressure needs but if someone does...that auto adjusting mode comes in pretty handy. Better to have something and not need it than need it and not have it.

[BTS]

+1 ... Agree with Pugsy here for people that can use APAP that don't have CSA... Totally worth it to have something that can do more than not, also APAP can run in straight CPAP mode..

[LSAT]

The insurance pays one price for a machine...whether it's a CPAP or an APAP. The Doctor shouldn't be concerned with the amount the insurance pays. He should just prescribe the best machine for his patient. The DME gets the same price whether they give you a "brick" with no data , a CPAP with fixed pressure or an APAP with adjustable pressure. The DME makes more money if they give you the lower cost machine.

[JerryL]

I will use myself for example ....my OSA is worse in REM sleep. Like 5 times worse in REM sleep than in non REM sleep.

Interesting. I hadn't realized this could happen.

My sleep study results give my diagnosis as "moderate OSAHS, and severe REM-related OSAHS." They gradually increased the pressure from 4cm to 9cm. My 8cm stage lasted 35 minutes, 53% of which was REM sleep -- and my AHI was 17.0. My 9cm stage lasted 70 minutes, including no REM sleep, and my AHI was 2.8. That's a huge drop in AHI. Based on this, they prescribed 9cm constant pressure CPAP.

That makes sense -- if the REM/non-REM factor is irrelevant. But if OSA can change during REM sleep, then I wonder if their results were valid -- because the 9cm pressure was never actually tested during REM sleep!

[JerryL]

Agree with Pugsy here for people that can use APAP that don't have CSA... Totally worth it to have something that can do more than not, also APAP can run in straight CPAP mode.

But now this makes me lean in the other direction, because my study does show several centrals (as we discussed in a previous thread). If APAP is contra-indicated for central and complex apnea, then maybe I'd be better off with the CPAP.

[BTS]

Yes but at the same time having the Auto you can still run it in CPAP mode...If you do go with CPAP make sure it's not the brick.. The ResMed AirSense Elite and the Dreamstation Pro are the ones to lean toward if sticking with straight CPAP..

[Pugsy]

But now this makes me lean in the other direction, because my study does show several centrals (as we discussed in a previous thread). If APAP is contra-indicated for central and complex apnea, then maybe I'd be better off with the CPAP.

APAP is only maybe contra indicated when people have complex sleep apnea where the centrals are happening only at certain higher pressures and we don't want the machine going there. Doesn't have to be higher pressures causing the centrals though. They could happen with as little as 4 cm pressure or they could be happening even without cpap pressure. CPAP isn't the only thing that can cause central apneas.

Don't let the presence of a few centrals scare you off apap....there are ways to work around it even in apap mode and changing pressures do make the centrals worse.

. But if OSA can change during REM sleep, then I wonder if their results were valid -- because the 9cm pressure was never actually tested during REM sleep!

This happened to me....I didn't get but 6 minutes of REM sleep during the entire night devoted to the titration so they never really got a chance to figure out pressure needs in REM and I came out of the titration study (the night from Hell) with a RX for CPAP at 8 cm but was worthless for REM sleep. Worked great for non REM sleep though.
In REM sleep my OSA was nearly 60 per hour...non REM it was 12.
With the 8 cm recommendation I was having REM OSA event clusters with maybe 25 events within a 30 minute REM period.
Ugly reports for sure and I felt like crap.

I don't know that you will need more pressure in REM....you may or you may not. Not everyone will see a huge difference.

[HoseCrusher]

Another perspective...

CPAP only works at one pressure. If your needs change during the night, you only get one pressure. With detailed data and not much variation in your needs this works.

APAP works at a range of pressures. You can set the minimum and the maximum according to the needs that you determine from your data. If the minimum = maximum pressure, you are now using APAP as a CPAP.

I would argue for an APAP that gives detailed data. It doesn't hurt to have more capability than you need and the extra capability doesn't effect the life of the machine.

A vehicle with a 6 speed transmission may only use the lower gears if all your driving is around town. However, if you get out on the highway you will find the higher gears useful.

[raisedfist]

It depends why you are using CPAP. In the acute setting, such as a hospital, you would want a static pressure to assist with conditions such as congestive heart failure (CHF), or hypoxemia related respiratory failure conditions such as ARDS, pneumonia, or pulmonary edema.

In the chronic at-home use setting, I can see straight CPAP being more useful than APAP with conditions such as CHF, obesity hypoventilation syndrome (OHS), and milder COPD. The constant optimal CPAP level would help those conditions more, most likely.

For OSA as the primary condition, I'd say a properly tuned APAP is superior to static CPAP. It's important on the APAP to set a good min pressure though, as a good amount of people seem to get set on 4 - 20 APAP for long-term, which sucks and in that case, a lab determined CPAP setting is probably better.

[TASmart]

Seems that in my case my biggest issue is controlling leaks, and using a single pressure seems to make leak control easier. That said, I have only in the last month or so got my pressure high enough to consistently keep my AHI near 1. I have not yet experimented with the Auto feature to see of things can be made better, still setting a new baseline. I can say that with too low of starting pressure events can occur before the machine can keep up, so I get events due to that.

[chunkyfrog]

Yes but at the same time having the Auto you can still run it in CPAP mode. . . .

DME's who avoid dispensing apaps HATE it when patients know
that any apap can also be run in cpap mode.
You get the more versatile machine, and it could let you bypass
unnecessary and expensive redundant sleep studies--their golden goose!

[Pugsy]

There is one data disadvantage to using the DreamStation Pro vs the Auto (apap) mode.
In fixed pressure mode Respironics machines don't flag Flow Limitations at all. A person could have a truckload of flow limitations and in fixed mode they simply aren't even flagged.

Always has irritated the heck out of me because flow limitations are big part of the auto adjusting algorithms in any apap algorithm.
If they are so frigging important why not at least flag them in fixed mode so people would know if they were happening or not.

For people who don't do well with auto mode with Respironics machines I will usually suggest that they still use auto mode but either use the minimum setting to equal the maximum setting so that only a fixed pressure is used or use a really tight auto range....so that they can still get FL flagging in auto mode because if they use fixed mode the FL flagging is turned off. It always shows 0 FLs but we don't know if they didn't happen or the machine just ignored them. In auto mode FL flagging gets turned back on.

Respironics machines only....doesn't apply to the other brands.

[Goofproof]

APAP's always better because they can be ran as CPAP's also. As far as centrals, neither one can treat centrals, though both may lower the number of centrals you have. APAP give you more options even CPAP if you need it. Jim