Lab Results not jiving with Home Results

As I wrote in another post, I was invited to participate in a study at my sleep center. They're conducting a trial to see how the Repironics Remstar Auto M Series A-Flex machine does a titration versus the equipment at the hospital. Hope is to do more home studies than in hospital studies. And I was asked to participate. For me, this was also a great chance for a free titration, as my original study was not conclusive, cos at the time I couldn't tolerate a pressure of 7cm, so my study was somewhat limited.

So I got a call from the sleep doc and I don't have a report in hand, but he told me that my results look good, that I responded well to the pressure, my oxygenation looks good, and the pressure range that showed on the machine was 4-9.

Well, here are some results from my home S8 AutoSet II CPAP Machine. Summary stats for week, graph for longer period, and last 2 days detail. Note it is only showing 6 of 7 days for the week, as 1 night I was at the sleep center.





For the past week, I'm showing a 95 percentile pressure of 13.2, low leakage, and I've also included detail from the past two nights. 11/1 with Fitlife, 11/2 with HC FlexFit HC432.

Now I understand there can be variations from night to night, and that I coulda had a strange night last week during the study. But results are not consistent with what I'm seeing at home. Could I just be responding different to the Resperonics machine at the lab from the ResMed machine at home?

Now I discussed with my expert at the sleep center, who told me I may have gotten used to a higher pressure, but the lower pressure may be all I need. And I'm prepared to lower my lower limit tonight. Last night I increased my lower limit from 11 to 11.6 while my upper was 15. And I'm prepared to reduce the lower limit to 4.

Anyone have any guess as to what's going on?

Was your sleep position different? Mask? Meds? anything different? Well besides the machines but that should be listed also.

At the lab I used the Fisher and Paykel Flexifit HC 432 FF Mask. At home, I've been using the same mask (leaves sore nose bridge mark) along with the Respironics FitLife FF Mask (leave sore on chin), as well as Activa LT on occasion, but I've been getting fairly consistent results at home.

There is a raging debate about the differences between the algoithms used by the Respironics units and the ResMed units. The two units react differently to apneas and hypopneas. So, whether one titrates more accurately than the other is open to debate.

Something about these results seems very fishy.

I am assuming here that your S8 machine has not been set to recognize apneas and hypopnas different from the 'default' settings (if that is even possible. with some machines it is).

I can understand how two different auto machines could arrive at different AHI's, but I would imagine the difference would be within a few cm/H2O. This is especially true of apneas.

Looking at your graphs, I see that your total AHI still contains a significant number of apneas, about 33 percent. As I understand this, you could be doing better in the AI department-- a good percentage of people have their apneas stopped at lower pressure, and much of the pressure support is used to minimize hypopnas.

So, on another machine in a sleep lab, you get a pressure range that is significantly lower. Most people can hardly breathe with a pressure of less than 6, let alone get good therapy. That is very suspicious in itself.

I see four possibilities here:

1. Your pressure really is too high. Some people actually have more events if their pressure is too high. Consider experimentally lowering pressure, but do it gradually (1 cm every 2-3 days or more
), and don't go below 9 unlesss you are seeing a noticeable improvement. Don't be surprised if it takes a week to see any significant change in your average AHI.

2. You did not sleep very well in the sleep lab, compared to how you sleep at home. Very few people do. The less sleepy you are, the less events you will tend to have.

3. Your sleep study was improperly 'scored'. Make sure you get a copy, and compare it to what you are seeing at home. Pay close attention to the AI/HI ratio, as that will be a big clue to what is going on. Also look how your body responded to pressure increases. Did they effectively suppress events?

4. Some external influence at home causes you to have more events than you would in the lab. I see you have a period back in September where you were doing much worse. Lots of suggestions on this board on things to do to improve sleep hygiene.

One other very remote possibility is that your machine is grossly miscalibrated in terms of pressure. A DME might be able to check the pressure calibration for you, or you could get a manometer from the sponsor of this board. You can also make your own manometer very easily.

Gary, we have the same machine and I'm a little suspicious about that 4-9cm pressure range. I imagine it would be pretty hard to breathe at that min pressure especially when you've been used to a higher pressure. I don't remember if you described the kind of night you had at the sleep center and what differences you noticed using this machine,etc. Thanks for keeping us posted on this interesting topic.

Titration Efficacy of Two Auto-Adjustable
Respiration 2008;75:48–54
DOI: 10.1159/000103515

Katrien B. Hertegonne, Bart Rombaut, Philippe Houtmeyers Georges Van Maele, Dirk A. Pevernagie

Abstract

Background: Auto-adjustable continuous positive airway pressure devices are widely used in titration procedures to determine therapeutic pressure levels in obstructive sleep apnea patients. However, differences in operational characteristics may influence the effect on the apnea-hypopnea index (AHI). Objectives: We compared the titration performance of two devices based on detection of inspiratory flow limitation, i.e. the Respironics REMstar Auto (RR) and the ResMed Spirit (RS). Methods: Fifty obstructive sleep apnea patients were recruited for a double-blind randomized crossover trial. Both devices were employed overnight by means of split-night polysomnography. The primary outcome was the AHI. Secondary outcome measures were the snoring index, pressure profiles and subjective appraisal of sleep quality assessed the morning after the sleep study. The Wilcoxon signed rank test for matched pairs was applied to assess differences between treatment conditions. Results: No significant differences were found in sleep parameters, subjective sleep quality and snoring index. The use of the RR was associated with a significantly lower AHI in comparison with the RS [mean (SD) 6.9 (11.6)/h vs. 9.4 (9.2)/h, p = 0.004]. This result was obtained at significantly lower pressure levels [P95 9.2 (2.3) cm H2O vs. 10.2 (1.5) cm H2O, p = 0.001]. Conclusion: While the RR provided a lower AHI than the RS at lower pressure levels, it could not be assessed whether this difference was relevant for clinical outcomes. However, this face-to-face comparison of Auto-adjustable continuous positive airway pressure devices seems useful for the assessment of titration efficacy.

Copyright © 2007 S. Karger AG, Basel

All Added emphasis mine for the sake of clarity.

timbalionguy wrote: I see four possibilities here:

1. Your pressure really is too high. Some people actually have more events if their pressure is too high. Consider experimentally lowering pressure, but do it gradually (1 cm every 2-3 days or more
), and don't go below 9 unlesss you are seeing a noticeable improvement. Don't be surprised if it takes a week to see any significant change in your average AHI.

Now, at the suggestion of my expert at my lab, I reset the autoset a bit radically (note to leegbt I changed the settings but at the direction of someone from the lab) from 11.6-15 down to 4-15. Yes a large range. But essentially this is a "home titration". Now I peeked at my numbers on the screen, and my pressure was around 10, my AHI was 3.7, and leakage was about 0.04 L/Sec.

I don't want to look at my detail until I have a few nights under my belt (superstitious.). But one nights numbers tell me that my pressure settings may have been too high. My initial titration wasn't successful as I wasn't able to tolerate a pressure of 7. And my original Rx was from 8-15. (which I had tweaked with acknowledgement of my sleep lab up to 11.6-15).

What is interesting is that my AHI is about the same as before. Anyway, I plan to grab numbers for a few more nights and then report back here.

DoriC wrote:Gary, we have the same machine and I'm a little suspicious about that 4-9cm pressure range. I imagine it would be pretty hard to breathe at that min pressure especially when you've been used to a higher pressure. I don't remember if you described the kind of night you had at the sleep center and what differences you noticed using this machine,etc. Thanks for keeping us posted on this interesting topic.

With my setting of 4-15 no trouble breathing. Yes, I was a bit concerned as well, but as usual, I go to sleep right away, and this wasn't a problem.

ozij wrote: Results: No significant differences were found in sleep parameters, subjective sleep quality and snoring index.

All Added emphasis mine for the sake of clarity.[/quote]Thanks for this. Very helpful. With one night of numbers, I'm thinking my original settings were off, and over time my body adjusted to higher pressure, and in my case of mild apnea (13), the extra pressure didn't seem to really cause me any problems. Or so it looks. Will report back when I get a few nights of numbers.

Thanks to all who responded. The support and info that all provide is very helpful.

My guess is that once you do your home titration in auto mode, you may do better picking a number and sticking to it in CPAP mode for night-to-night treatment instead of always running in auto mode. Then you can titrate over time using specific constant pressures. My guess is based on nothing more than your statement that you had trouble tolerating pressure before and my wondering if those clusters of relatively long apneas in your ResScan reports might be some sort of intermittent pressure-related centrals.

Ozij, thank you for posting that article, it answered the burning question at the back of my mind, "Would the S8 be better(interpret that as "perfect") than our MSeries machine? Now I can make room for something else to worry about. Dori

Not to be a fly in the ointment....BUT....
as we always talk about here.....
it's how you feel....not the "clinical outcome."

As we also talk about....one night does not a titration make.

Having spent a year on an Mseries auto....with very good results,
and now having spent 4mths on an S8 auto,
I have experienced significant differences in my sleep parameters
and quality of sleep.
The graphical proof that I can get excellent therapy without
the machine algorithum chasing events has me in straight cpap mode.
The Easy Breath and EPR have made that possible.
Two weeks in straight cpap mode are producing those magical
$1million dollar nights.....just had another one of those nights,
last night. I am experiencing sleep like never before in my life.

Is it just the machine?....mostly.........
it is also diligent practice of Barry Krokow's sleep techniques.
I am winning the clock watching game.
I am Closing my day with the SOLO technique
and my TFI balancing is putting me to sleep....fast....
when I do wake, it is putting me back to sleep....fast.

Please tell me what double-blind randomized crossover trial
can gauge those parameters.

Not trying to sell any machines, diss any studies or cause undue worry,
just my experience.

Edit:

...ah....just as an aside...
when I got the S8, I set it up exactly as my Mseries was,
tried all the features of the machine,
changed my auto pressure settings,
changed to straight cpap mode...at different pressures.
All of this was accomplished by watching my data, daily.
Making modification decisions bases on said data.
All of this was accomplished without any outside interference
or delay from Drs, DME, alleged RT or sleep lab directors.

I am still here....alive and kicking....
like never before in my life.

All good points, Carbonman.

But . . .

I would think that all the big brands can deliver straight pressure effectively for night-to-night treatment, if that's what you're using.

And for those of us who have benefited from the info on this board, we may have benefited more from DMEs, lab directors, RTs, and docs than we even know.

jnk wrote:All good points, Carbonman.

But . . .

I would think that all the big brands can deliver straight pressure effectively for night-to-night treatment, if that's what you're using.

Uh... Yes and no, jeff.

Carbonman said it: "The Easy Breath and EPR have made that possible"

Same for me. The Autoset I'm trying, still on Auto mode, goes to a pressures I can tolerate only thanks to EPR and EasyBreathe. That pressure (in any mode) would have impossible for me on my 420E which has no kind of exhalation releif, and on a Respironics, whose attempt to give me pressure relief misfires.

O.