Runaway pressure increase with resmed auto S8

[barbpsleep]

Sorry that this is long. But it's kind of a complicated situation that my DME and the REsmed rep haven't provided a solution for that seems logical to me.

I've been using a resmed S8 auto vantage on a trial for about a month. I used a Respironics cpap with c-flex for about a year and was still waking more than seemed reasonable. A home test with an auto REspironics with c-flex showed I needed a pressure of between 5 and 8 95% of the time, with no events occuring at 10. Because I'd heard good things about the S8 and liked the size for traveling, I asked to try it rather than the respironics unit, which must have been the classic model.

Though I sleep better with the auto unit, there's something weird about the S8 that interferes with falling asleep. I wonder if anyone has had a similar experience. Within 30 secs. of starting use, it begins to steadily increase the pressure - to 9 within 2 minutes, to 11 by 5 minutes - all while I'm wide awake and breathing normally. I have no problem breathing while awake, at rest or while exercising. It's not a matter of using the ramp/settling feature, but rather than that even while still awake, it increases beyond what the data shows I need during sleep.

The DME and Resmed nurse/rep couldn't explain it and seemed surprised. The Resmed nurse said perhaps there's something about my physiology - a narrowed air passage. Seems to me that would have an impact during the day too. I do have a deviated septum and hypothyroidism that's controlled with med., though I still have a thyroid nodule. But all that seems irrelevant given the respironics data showing I needed only a pressure of 8 most of the time.

The rep also wondered if perhaps my airway reacts to the pressure by narrowing and that maybe I'd do better with a model that reduces pressure on the exhale, which resmed doesn't offer on the auto. Should I try the new remstar? There are mixed reviews of it here, but the a-flex sounds like a good idea.

Has anyone else had a similar experience with the S8. Any further reviews of the REmstar M I travel a fair amount and like the size and style of the S8. a month ago, the DME said there had been problems with the Remstar, but now says these were corrected in recent models.

I appreciate any thoughts and suggestions.

Barbpsleep

[dsm]

I'm using an S8 Vantage at the moment.

What you describe is *not* normal. My 1st action would be to take it back. The only things that can (or should) make the pressure rise are loud snoring, some types of flow limitations & recognised obstructions.

good luck

DSM

[ozij]

Barbpsleep
I have no personal experience with your machine. However, you should know that auto adjusting machines are based on software, which defines
a. what is an event and
b. once identified, how that event should be responded to.

These definitions vary from one company to the other, and there are cases where one company's automatic algorithm (set of rules for identifying events and reacting to them) is good for a patient, while another company's agorithm is not. Your specific breathing pattern, affected as it is by your deviated septum, may be confusing the s8. In other words, you're not having breathing problems, this machine's algorithm is misreading your normal breathing.

It is not impossilbe that for you, a Respironics machine is better than a Resmed. For me, a Puritan Bennett GoodKnight 420E (very small, very light and automatic) was better than a Respironics machine.

Can you get an identical s8 loaner from the DME just to see how that one reacts to your breathing pattern?

Can you have a trial of a 420E? (If you can, make sure to let us know, since the 420E has a software switch that has to be activated for some people to keep it from runaway pressure). It has no pressure relief - but your pressure is low so that might not be crucial. It's hard to beat for travel convenience.

The Respironics with A-flex is considered a very good machine by those who have tried it.

Here's cpap.com's comparison chart of the five most popular self adjusting machines.
O.

[barbpsleep]

Thanks, Ozij. Your theory about the algorithm is the first one that makes sense. I tend to breathe in a relaxed way, with long inhales and exhales. I had wondered if it might be reading a pause between inhale and exhale as an apnea, so I tried to speed up the breathing a bit. Didn't seem to affect the increasing of the pressure. But it's a good theory to consider further.

So, you're happy with the 420E? I has asked the DME about other smaller units, and he seemd to think there were problems with the other smaller units, I think including Puritan and Bennett. Don't know if it was noise or reliability. But I think I'll ask further about other options, including this one.

Thanks again,

Barb

[RiverDave]

barbpsleep,

I am new to the cpap world and am using the same machine as you. I have found that the S8 reacts to a couple of different factors when I first turn it on: 1) position in bed - side vs stomach vs back, 2) breathing patterns while I'm still awake - especially yawning. The unit does tend to "reset" itself back to the pre-event pressure in short order once I settle down for the night. I never considered it a problem becasue I attributed the changes in pressure to changes in my airway. I'll be interested in what you find out.

Thanks

Dave

[kteague]

What is the pressure range your machine is set to or is it left wide open? If snores or something else is is causing it to increase beyond your therapeutic pressure, setting the maximum pressure at your therapeutic pressure would address your events without running away. Unless it's malfunctioning of course.
Kathy

[beegee]

Barbpsleep, I can identify with what you are describing with the S8. I happily used this machine from December 2005 until March this year when I sent if to be checked because it cut out a couple of times and the on/off switch was a bit loose. It came back with a new switch, and they had installed upgraded software. I noticed just the sort of "runaway pressure" thing you describe and found it difficult to get to sleep even after increasing my ramp time to 30 mins. The pressure reading I got each morning had increased to an average of 13.5 where it had been 12.5, and I was having difficulty with mask sealing which I hadn't had before. The increased pressure resulted in more noise also and I was having trouble sleeping through the night, where before I considered the machine quiet. I rang and talked to a technician as I thought the algorithm must have been changed, but was assured that the software change only related to recording of data and the algorithm was the same.

When this machine was replaced with a new one as part of the recent recall, it behaved in just the same way and, by this time feeling very tired, I changed to a Respironics Remstar Auto, which seems to suit me well, and is extremely quiet. I also tried the newer M series Remstar for a while and chose the older version (otherwise known as "classic" or "tank"), as I found the noise level disturbing with the M series. I have learned that for me, quietness is very important.

I hope you are able to experiment with different machines, and find one that suits you.

Regards,
beegee.

[Treesap]

Though I sleep better with the auto unit, there's something weird about the S8 that interferes with falling asleep. I wonder if anyone has had a similar experience. Within 30 secs. of starting use, it begins to steadily increase the pressure - to 9 within 2 minutes, to 11 by 5 minutes - all while I'm wide awake and breathing normally. I have no problem breathing while awake, at rest or while exercising. It's not a matter of using the ramp/settling feature, but rather than that even while still awake, it increases beyond what the data shows I need during sleep.

Is it set for a certain pressure in the beginning? I use this machine, and my starting pressure is 6. I can set the amount of time I want it to stay at that pressure. That time is anywhere between 5 and 20 minutes. Then it starts in auto mode.

Ask your DME if the starting pressure was set correctly. They should check this. I was told by the DME that only they could change the auto pressures. I'm sure someone else here knows if you can do it yourself or not.

Where's Rested Gal? She knows everything.

[Snoredog]

I couldn't use a Resmed Spirit for the exact same reason, two breaths and it was increasing all the way to the maximum set limit. When it wasn't doing that I would snore and it would drive up because of that.

Do you find at times you seem to forget to breathe? Because I do that and it drives that maker's machine absolutely nutso. It seems to think that pause in breathing is a apnea and tries to respond to it, of course you are not having an apnea.

Drag out your PSG and look for CA or MA events listed on your PSG report and you'll have your answer. IF there is, find a new DME as the one you have don't know squat about what they are doing.

A-Flex is a much more comfortable machine to use anyway, that feature alone is worth the price of admission.

[GoofyUT]

Hold on there, Barb. What you're describing is perfectly normal for the ResMed S8 Vantage and many of us here, as well as several sleep labs, have observed and documented the very same phenomenon. It has to do with the "settling time" parameter on the Vantage. If "settling" is NOT enabled, the Vantage begins scoring flow degradations as soon as it starts up and begins titrating to treat them. This includes what you would consider to be your "normal" wakeful breathing, which is NOT the same as the autonomic breathing that you do while asleep. The Vantage gets confused by your wakeful breathing and tries to treat it by increasing pressure, while it really is designed to score and treat only autonomic breathing while you are asleep. It is for this reason that they include the "settling" function. That SHOULD be enabled and set to the period that it normally takes you to settle in and fall asleep. By doing so, you're disabling the scoring algorithm during that time, and the machine will simply plug along at its lowest auto pressure until you've usually fallen asleep. It'll then begin scoring flow degradations of your autonomic sleep breathing, and treat them VERY effectively.

I struggled with the very same thing until I figured out the "settling" function, set it to 20 minutes or so, and VOILA, the increases in pressure while I was awake ceased immediately! And, my AHI dropped sharply too, since it was not scoring hypopneas artifactually while I was awake. So ENABLE SETTLING and your problem will be solved.

Unfortunately, I didn't respond well to the flow dynamics of the ResMed algorithm, so I switched to a REMstar Auto, which I respond much better to. But, it sounds like you do respond well to ResMed's algorithm, and I think that it is a GREAT machine for those who respond to it well; The very BEST in terms of human factors design, form factor, size and travel-friendliness.

So, RELAX, enable settling and you'll be fine!

Hope this helps.

Chuck

[ozij]

The Resmed it set to respond with more pressure to either of these 3 events:

Apnea
Flow Limitation
Snore

(see Three Lines of Defense

A misidentification of any one of those - whether you are awake or asleep will cause runaway pressure.

My 420E
Yes, I am happy with it.

* Reliability: I got my first machine at about April 2005. it lasted a year. It was noisy and whiny.

I got my second machine after one machineless night (the first was still under warranty) it's quiet, and has been working fine.

What with machines being under warranty for a long time, and the fact that both Resmed and Respironics have had recalls - I don't know if the reliability issues should trouble you. PBs reliability issues were a number of years ago - and yes they were there not only for me' other members of the forum (snork1, janelle, snoredog) have also run into them.

Sellers of anything will frequently tell you: "Oh, we don't carry that because it has reliability issues" even when that is not ther reason they don't carry something. Thereby implying that competitors who do carry that stuff are : stupid or incompetent or ready to give you second rated merchandise. They also say that when their markup on other equipment is higher.

My RT said, when I bought the PB that she wouldn't give it to patients whose pressure needs were high, because "the motor is weak" - I'm not amechanic (neither is she...) but that sounded sensible.

Your DME did tell you Resmed had problems, and they were solved...

*Noise: Again, this true of other machines as well: some are noisy, some (identical machines) from the same company are not.

Noise is always higher when pressure rises.

The humidifier on the GK 420E acts as a good noise buffer.

Its software is still easily obtainable. And, like I said, on this machine you can tell: "Hey, this flow limitaition is my natural healthy way of breathing, don't react!" and the machine obeys.

O.

[barbpsleep]

Thank you all for sharing your insights and suggestions about the runaway pressure problem. I find it so interesting that the collective wisdom here far exceeds that of my DME RT and the resmed nurse/rep.

I hadn't thought before about the greater variation in wakeful breathing compared with the automatic breathing during sleep. I am aware that I kind of pause between inhale and exhale when I'm very relaxed. I find it to be a good thing, kind of centering. So, maybe that contributes to the misread, though the pressure didn't stop increasing when I deliberately breathed more quickly.

In any case, I enabled settling last night and it helped. I woke once during the night, noticed the pressure reading was at 7, and then watched it start its increase. When it got past 10, I turned it off and on and went back to sleep.

I'll try the suggestion of further decreasing the upper limit. Empowered with the secret access to the clinical menu, I already decreased it from 20 to 16, but since my study showed 10 was sufficient, maybe I'll go a bit lower.

Noticing another post about the impact of GERD, I will try going back on Prilosec OTC, and I've got to make an appt. with my endocrinologist to check on my thryoid levels.

Not sure if I I'll try another machine, but maybe I'll stop by the DME next week and give them listen.

Thanks again for your many thoughtful suggestions. The members of this forum demonstrate the value of being proactive and inquiring, getting needed information, and then sharing it supportively with others. You rock.

Barbara

[Slinky]

THANK YOU yet again, GoofyUT. I didn't know that about the Settling time either. I could never quite grasp just what Settling time was.

My understanding was that the Elite didn't have provisions for Settling time yet it has shown up in the AutoScan 5.7 Patient Notes for the Elite at various times w/different settings.

For instance when I first got this Elite:

01/09/2007 09:18 Downloaded compliance data from S8 Elite - Data Card
FG Serial Number:200603xxxxx FG Software Id:SX396-0202______
Mode : CPAP
Set Pressure : 8.0 cm H2O
Minimum Pressure : 4.0 cm H2O
Maximum Pressure : 20.0 cm H2O
Start Pressure : 4.0 cm H2O
Ramp Time : 0 minutes
Maximum Ramp Time : 30 minutes
EPR Setting: 3.0 cm H2O
EPR Type: Fulltime (Always On)
Settling Time : 20 minutes
Maximum Settling Time : 45 minutes

Then later after the DME's RT had access to it:

01/22/2007 08:02 Downloaded compliance data from S8 Elite - Data Card
FG Serial Number:200603xxxxx FG Software Id:SX396-0202______
Mode : CPAP
Set Pressure : 8.0 cm H2O
Minimum Pressure : 4.0 cm H2O
Maximum Pressure : 20.0 cm H2O
Start Pressure : 4.0 cm H2O
Ramp Time : 0 minutes
Maximum Ramp Time : 20 minutes
EPR Setting: 3.0 cm H2O
EPR Type: Fulltime (Always On)
Settling Time : 5 minutes
Maximum Settling Time : 30 minutes

And my original Elite (set up by the DME's RT):
12/17/2006 10:26 Downloaded compliance data from S8 Elite - Data Card
FG Serial Number:200603xxxxx FG Software Id:SX396-0202______
Mode : CPAP
Set Pressure : 6.0 cm H2O
Minimum Pressure : 4.0 cm H2O
Maximum Pressure : 20.0 cm H2O
Start Pressure : 6.0 cm H2O
Ramp Time : 5 minutes
Maximum Ramp Time : 15 minutes
EPR Setting: 0.0 cm H2O
EPR Type: Fulltime (Always On)
Settling Time : 5 minutes
Maximum Settling Time : 30 minutes

[barbpsleep]

GoofyUT, I wonder what helped determine that your airflow fit the remstar better than resmed? Who was able to differentiate between the algorithms?

And, also, is that a German Shorthaired Pointer in your photo? It's a beautiful dog.

Thanks again,

Barbara

[Snoredog]

[quote="barbpsleep"]GoofyUT, I wonder what helped determine that your airflow fit the remstar better than resmed? Who was able to differentiate between the algorithms?

And, also, is that a German Shorthaired Pointer in your photo? It's a beautiful dog.

Thanks again,

Barbara