Why can't machine be 100%

[Fireguy24]

I've been on apap now for a week and only started charting the efficiancy data. I'm curious is to why the machine doesn't eliminate all apneas/hypopneas one has during the night. I understand nothing is 100% perfect, but the amount of episodes that it doesn't help or fix seems high. I am just a newbie, so please forgive my ignorance on this.

Monday - PRESS = 10 , LEAK = .06 , AHI = 9.6 , AI = 2.1 , HI = 7.5

Tuesday - PRESS = 12.4 , LEAK = .1 , AHI = 7.1 , AI = .6 , HI = 6.5

Wednesday - PRESS = 10.8 , LEAK = .14, AHI = 7.3 , AI = 1.9 , HI = 5.4

Average - PRESS = 11.06 , LEAK = .1 , AHI = 8 , AI = 1.53 , HI = 6.46

Glen

[packitin]

I can't figure this out. I've got the same mask and equipment, but never had an AHI that high?
How many times do you take off the mask during the night?
Do you cut off the machine before you take off the mask?
What was your pressure during the sleep study?
What does your doctor say about this in the follow up visit? (if you've had one yet)
When you clean the mask each day, do you make sure its attached back correctly? (sometimes if one doesn't snap it back on correctly, it will leak)

[GuyK]

Fireguy, it's not like I'm as far along as most of the others in this forum, but I have the same machine. My take on it is that the "auto range" is set so that if the machine detects apneas, then pressure is increased to the point of them abating. If the mask starts to leak, then the pressure is not cranked up any higher.

So, to my untrained eye, it looks like you've topped out at a certain pressure, with a fairly low leak rate but AHI hasn't gone down that far.

I think that means the upper pressure range should be moved up a little (around here, the recommendation is to move small steps at a slow pace).

In my case, my range is set from 10 to 20. I average between 10.8 and 11.8 every night, with fairly hefty leak rates (time to try a new mask) running over 0.50 most of the time. But my AHI is always under 5.0. It would be even better if I had a lower leak rate.

In your case, your leak rate looks fairly good, but your AHI still needs to come down. The pressure has to go up for that to happen.

You're not all that far off. Your doctor will ask you if you are feeling better.

[GumbyCT]

Glenn,
It's all about how the machine is setup. Your pressure maybe isn't right for YOU or the Resmed algorithm or even an auto. Time to read up on these things. Keep in mind you want to keep your AI below 1 and that most folks who don't have a CPAP may be having more events than that but most don't have any idea they are. Your sleep position can also help too as can meds and/or cocktails.

As you said - nothing is perfect.

[kteague]

Glen, I'm wondering if most of your events are happening around the time the ramp stops and the machine is trying to get the pressure up enough to help. I personally use a very short ramp as I fall asleep quickly, and don't want a lot of unprotected time. If your pressure range was set to start at 4, it would have quite a climb to get to where you need it. Raising your lower end to where the doctor prescribed may make your numbers even better, although that AI looks pretty good. As far as perfection, I guess if one used a fixed pressure a little higher than titrated it could be, but most don't want any higher pressure than necessary due to increased leaks and more possible side effects like air into the stomach or for those predisposed, central apneas. As things settle down, you may see the occasional 0.0 night. These machines are good but not so good as to not be affected by a prolonged spell of coughing or holding ones breath while changing positions (I do that a lot), etc. Hope your mask quest is not too lengthy or expensive.
Kathy

[klaimguy]

The way I fixed mine was going up a step a night. For instance, set a basement of 10, then 11, the 12 until you get your AHI under 3. It took me about a week. My theory, whether right or wrong is that the machine doesn't react to the apnea fast enough. So by increasing your basement, your helping your machine react more quickly. My AHI now hovers at the .8 to 1.2 level. Hope that helps. I will say that I don't use the ramp feature.

[DreamStalker]

I've been on apap now for a week and only started charting the efficiancy data. I'm curious is to why the machine doesn't eliminate all apneas/hypopneas one has during the night. I understand nothing is 100% perfect, but the amount of episodes that it doesn't help or fix seems high. I am just a newbie, so please forgive my ignorance on this.

Monday - PRESS = 10 , LEAK = .06 , AHI = 9.6 , AI = 2.1 , HI = 7.5

Tuesday - PRESS = 12.4 , LEAK = .1 , AHI = 7.1 , AI = .6 , HI = 6.5

Wednesday - PRESS = 10.8 , LEAK = .14, AHI = 7.3 , AI = 1.9 , HI = 5.4

Average - PRESS = 11.06 , LEAK = .1 , AHI = 8 , AI = 1.53 , HI = 6.46

Glen

WHat are all the settings on your machine ...

min pressure?
max pressure?
ramp time?
start pressure?
EPR setting?

Keep in mind that there is also variability due to physiological factors like leaks (mouth and/or mask and sometimes even hose leaks), what position you sleep in (side, stomach, or back, or all), medications you take, what you ate last before going to sleep and when you ate it. Even if you could keep all of these factors constant every night, there would still be some variability in your breathing cuz you don't breathe exactly the same from breath to breath, hour to hour, or night to night.

The key to understanding and using your data to optimize treatment is to use the statistical values of averages, 95th (or 90th for Respironics) percentiles, and long-term trends (weekly and/or monthly). Be patient, collect data, don't change too many variables (machine settings, masks, etc.) too frequently.

[Fireguy24]

My settings are:
Min Pressure: 6
Max Pressure: 15
Ramp Time: 15 min
Start Pressure: 4
EPR setting: 3 (fulltime)

My pressure from the sleep study was 11. So my family Dr set the script at 7-15. I tend to be a back sleeper, trying to stay on my side but I have no control once asleep. No meds or OTC pills at the moment. No beverages since I started treatment hoping that would help. Man, I could use a few at the moment. I have taken the mask off once to go to the bathroom, other than that it stays on. I do take the mask off before I turn the machine off. So thats probably messing with some numbers. I do have bad allergies that I'm getting allergy shots once a week for at the moment, and I'm thinking I should bring my lab reports to my ENT Doc as he has more knowledge than my general family doc in this area. I do a leak test laying down and get an "excellent" reading every time.

Thanks for all your input.
Glen

[DreamStalker]

My settings are:
Min Pressure: 6
Max Pressure: 15
Ramp Time: 15 min
Start Pressure: 4
EPR setting: 3 (fulltime)

My pressure from the sleep study was 11. So my family Dr set the script at 7-15. I tend to be a back sleeper, trying to stay on my side but I have no control once asleep. No meds or OTC pills at the moment. No beverages since I started treatment hoping that would help. Man, I could use a few at the moment. I have taken the mask off once to go to the bathroom, other than that it stays on. I do take the mask off before I turn the machine off. So thats probably messing with some numbers. I do have bad allergies that I'm getting allergy shots once a week for at the moment, and I'm thinking I should bring my lab reports to my ENT Doc as he has more knowledge than my general family doc in this area. I do a leak test laying down and get an "excellent" reading every time.

Thanks for all your input.
Glen

To reduce variability and optimize your treatment, I would raise both min pressure and start pressure to about 9 ... then collect a week or two of data without changing anything else. Important to keep an eye on leak values (your appear to look fine for now but only looking at your nightly leak curve can anyone know for sure).

[rested gal]

Fireguy, I agree with DreamStalker that you should raise the minimum pressure setting to 9, instead of the 6 the minimum is presently set on.

Even at your current settings, your AHI is good, imho. I'm saying that because the AI (apnea index) is quite low each night. It's the HI (hypopnea index) that is inflating the AHI total. Every ResMed S8 machine I've used reports about double, or even triple, the "hypopneas" for me that any other brand of machine does. This doesn't mean that a ResMed S8 is letting more hypopneas through, or that a ResMed S8 identifies hypopneas that other brands "miss." It's simply a difference in the way each manufacturer designs their machines... what threshold they use to say, "This amount of flow limitation is now an Hypopnea."

There is no hard and fast definition of "hypopnea." So how much restriction in air flow there has to be before it gets marked as "hypopnea" depends on how each manufacturer defines it. Doesn't mean one is right and another is wrong.

When I use a ResMed machine and want to compare my data with other brands (Respironics and Puritan Bennett) I have, I mentally cut the ResMed S8 hypopnea report in half. Then my data from any machine comes out to be essentially the same. But that's just me, and my opinion. I'm not a doctor or anything in the health care field.

My edit: Added "S8" to all my references to ResMed machines in this old post, since the definition of hypopnea was changed by ResMed in the later S9 series machines.

[hobbs]

I would change the EPR to 1 & bump the low to 10.

[Fireguy24]

Thanks all.
I'll do some tweak'n with the lower pressures as suggested. How would changing the EPR to 1 change anything? Would it be because the pressure is more of a constant in the mask itself, therefore the machine won't work so hard going up & down with pressures. Maybe?
Thanks again.
This forum is absolutly amazing.
Glen

[GuyK]

Although I didn't follow the somnodoc's reasoning, he told me to drop my min from 10 down to 6, in order to try and reduce HI (overall AHI is good -- pretty much always under 5.0). He implied that the ResMed machine that he spec'd for me does tend to over-report hypopneas (my interpretation).

I'm not running EPR -- I've been fine on exhale (at first, there is noticeable resistance, but later if I wake up again, it feels very natural to me).

But -- if I do get up in the middle of the night, I always switch off the machine first and then release the mask. I could easily see how taking off the mask first could skew the numbers a bit. In fact, that was the first question the R/T asked me when I told him I was having leak issues.

[ziggytosh]

I've been on apap now for a week and only started charting the efficiancy data. I'm curious is to why the machine doesn't eliminate all apneas/hypopneas one has during the night. I understand nothing is 100% perfect, but the amount of episodes that it doesn't help or fix seems high. I am just a newbie, so please forgive my ignorance on this.

Monday - PRESS = 10 , LEAK = .06 , AHI = 9.6 , AI = 2.1 , HI = 7.5

Tuesday - PRESS = 12.4 , LEAK = .1 , AHI = 7.1 , AI = .6 , HI = 6.5

Wednesday - PRESS = 10.8 , LEAK = .14, AHI = 7.3 , AI = 1.9 , HI = 5.4

Average - PRESS = 11.06 , LEAK = .1 , AHI = 8 , AI = 1.53 , HI = 6.46

Glen

Hi Glen. Looks like you've gotten a lot of great advice already, and I don't have much to add as a newbie myself, except to back up your experience with my own. I have had the same machine, the Autoset II, for a little over a week, having switched from an Elite II. My experience is similar, but I have seen some improvement with a mask switch.

For the first few nights, I was getting AHI of 7-10. This was only a slight improvement over a similar pattern I had on the Elite II. The variability for me on both machines was always in the HI. AI would be <1 and HI would range from night to night. I was using a ResMed full-face mask, the Quattro. A few nights ago I tried a nasal mask that my dad gave me -- Fisher & Paykel FlexiFit 407. I've seen an improvement each of the last three nights, with AHI's of 4.5, 5.2 and 6.0 -- again with the AI being <1 and the HI varying from night to night. As I think about it, I've got a deviated septum and it may just be that the nasal mask applies more direct pressure to my sinuses and keeps things opened up at the top, so it works better overall.

My leak rates aren't quite as good as yours, so I'll have to work at that (I also have some bad habits of opening up the mask to get at itches and taking it off before switching off the machine). My reported pressures are very similar to yours, ranging from 10 to 12. I have my range set from 8-20, but after reading other comments in this thread may bump that up to 10-ish, along with working on being a better mask-leak citizen. Anyway, I'll follow your experience and give you any updates on things that work for me, as it seems like we are having similar experiences with the same machine.

[rested gal]

Although I didn't follow the somnodoc's reasoning, he told me to drop my min from 10 down to 6, in order to try and reduce HI (overall AHI is good -- pretty much always under 5.0).

I don't understand the doctor's reasoning either, and it's probably a good thing you didn't follow his recommendation to lower the minimum. Or at least, if you did try it his way for awhile, you went back to your better minimum setting of 10.

In my case, my range is set from 10 to 20.

He implied that the ResMed machine that he spec'd for me does tend to over-report hypopneas (my interpretation).

I think he's right about that, although (to be quibble-ish) I probably wouldn't call it over-reporting, which implies mistaken reporting. It's just a difference in manufacturers' definitions of how much flow limitation there has to be for it to be called a "hypopnea."