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Sierra

Sierra
Joined Jul 2018
Bio

CPAP: AirSense 10 AutoSet

Max Pressure: 13 cm

Min Pressure: 12.2 cm

Ramp: Auto

Ramp Start: 8.4 cm

EPR: 3, Ramp Only

Mask: ResMed AirFit P10 Nasal Pillow

Canada

Sierra
Joined Jul 2018
Bio

CPAP: AirSense 10 AutoSet

Max Pressure: 13 cm

Min Pressure: 12.2 cm

Ramp: Auto

Ramp Start: 8.4 cm

EPR: 3, Ramp Only

Mask: ResMed AirFit P10 Nasal Pillow

Canada

Another update on my testing of Auto vs Fixed CPAP pressure effectiveness. I have kind of gone through three phases with this testing:

Standard Auto Mode - This is the setup where most machines are put in for patient use. A common starting point is 5 cm to 20 cm. Then if one is fortunate to have an attentive sleep technician, this range gets a further refinement based on data collected over the first month or so. Since my trial machine was not compatible with SleepyHead, I don't have a record of the first two weeks, but I recall I started out something like that. Fairly quickly I reduced that range based on what I was seeing in SleepyHead to the 10 cm to 15 cm range. The outcome of this phase was getting AHI fairly reliably under 5.

Limited Auto Mode - My next strategy was to try and optimize the set pressures by narrowing that range more and more. I also, with thanks to a post by sleeptech at this forum switched to a EPR on ramp only. Using EPR on ramp only resulted in a reduction in pressure, and that was further improved by narrowing the range of pressures allowed. The outcome of this phase was getting AHI down to the 3 range.

Fixed Pressure CPAP Mode - My third and latest strategy has been to try the fixed pressure mode. I was getting suspicious that even with a narrow pressure range, the machine was running pressure up too high and was increasing the frequency of central apnea and hypopnea events. My thoughts were to keep reducing this fixed pressure setting until obstructive events started to increase. Unfortunately I have not been very disciplined about leaving the pressure at one setting long enough to collect sufficient data. But, that said a pressure of about 12 cm gave me an AHI of 2.3 over 15 days. And now at my latest longer term trial at 11 cm for 19 days I have an average AHI of just under 2. For many with basic apnea that probably does not sound that great, but for me where most of my apnea is central, that is pretty good.

What is my conclusion in all of this? Well, first off, one person does not make a study. My AHI at diagnosis was about 34, and there was very little central apnea identified. However, with PAP treatment, central apnea increased, and really has not decreased after the 6-8 weeks that some studies have shown. It stayed high with my apnea remaining mixed, with the highest portion being central. So these results may only apply to someone in a similar situation, or where there is at least some central apnea in the picture. But, for me, it appears a fixed pressure CPAP mode has been much more effective than a wide open auto mode, and better even that a limited pressure auto mode.

Could someone get to this point by starting with a fixed pressure CPAP machine instead of an Auto CPAP? Yes, possibly, BUT, I think it would be very difficult unless the machine stores detailed data on a SD card that can be read by SleepyHead. One would have to try one pressure for at least a week if not 2-3 weeks, and then try another pressure. It would take a long time, but I suspect it can be done. The Auto machine allows you to identify the range of possible effective pressures very quickly, which in turn makes the testing for ideal single pressures quicker. And it is kind of a moot point anyway as the last time I checked the cost of the ResMed Autoset is only about $80 more than the ResMed Elite fixed pressure machine (which has data capability). To me it makes much more sense to start out with the Auto machine, and then switch to fixed CPAP mode later if that works better.

Hope that helps those who are dealing with this issue. The biggest benefit in all of this for me is that I find my sleep more comfortable now with a fixed pressure. A fixed pressure of 11 cm is certainly more tolerable than an auto mode which was running pressures up to 15 cm, while potentially causing more apneas than it was avoiding. Here is my sleep report from last night which is better than average for me, but somewhat typical. And I will also attach the Statistics page which kind of details my journey through these three phases identified above. To date I have now tried 30 different setups!

Mike here is an example in SleepyHead of how the DreamStation behaves, and what I mean by a more bumpy ride.

Notice how the pressure goes through very large swings both up and down. And on top of that you can see the spikes in pressure which happen periodically. That is the machine doing the hunt and peck method to see if the pressure should be changed. In comparison the ResMed gives a much smoother ride. But, if one does not notice it, then both machines can do the job.

The ResMed AirSense 10 has both a standard and a soft response. So, you can dampen out the response even more if you want to. I have never tried the Soft response setting, so don't know what it really does from experience. I see it there as an option though. The For Her mode is slightly different than the response setting. It gives a quicker early response to hypopnea, and holds the increase longer. It will not go above 12 cm in response to obstructive apneas, so that setting will work for some, but not others that need higher pressure. I was not aware of the For Her differences when I bought my AirSense 10 machine, or I would have bought one. I thought it was just an appearance difference.

Flex on the DreamStation is a bit different than the ResMed EPR. The EPR gives a full 1, 2, or 3 cm reduction in exhale pressure. The Flex technique although it uses the 1, 2, 3 number system, does not really reduce pressure by those increments. It just changes the shape of the pressure switch from inhale to exhale. And, to my knowledge DreamStation does not have the option to use Flex during the Ramp only. It is either on or off the whole time the machine is running. Here is a link that explains how different manufacturers do the expiratory relief.

Comparing Expiratory Relief in Different Machines

You may also want to check with your insurance company directly for any other options. My son had employer Sun Life insurnce, and he worked out a deal with them to buy both a home machine and a travel machine, on line for a total cost of about $2000. The insurance company went for that as it saved them about $500. Not totally sure of the value of a travel machine, but in case you are interested it may be an option.

As for the two choices of machines, they do basically the same thing, and both are supported by SleepyHead. If you are going to try them both, I would suggest downloading SleepyHead so you can see how each machine operates for you personally. They do behave a little differently. You can also access this basic SleepyHead manual for some help using it. You do need a SD card reader and a PC of Mac computer for it though.

The Dreamstation uses what has been called a hunt and peck method of controlling pressure. It bumps pressure up every 10 minutes or so to see if breathing is improved. If it is not, then it ramps back down again. It results in a more "bumpy" pressure ride during the night. The ResMed tends to respond faster, and then maintain the pressure longer, giving a smoother pressure ride. But, if you use SleepyHead during your trial, you will see that. SleepyHead will allow you to use multiple machines in your same setup.

My preference in the two machines is the ResMed AirSense 10 AutoSet For Her. The For Her version gives you a choice of another algorithm which you can use at your option. It also offers the standard one with a mode change. The price on both machines are the same.

Other than the smoother pressure ride, the nice feature with the ResMed is that it lets you use EPR (expiratory pressure relief) during the ramp only. That is better than having it on full time or off full time in my opinion. It also offers an Auto Ramp feature that I find very comfortable. Instead of ramping up pressure, it holds the pressure at your selected level until you go to sleep. So you get the comfort of EPR and a fixed pressure while you are awake, and then it switches over to more effective treatment pressure with no EPR, when you fall asleep. The only bit of an issue is that some sleep clinics can't be bothered to set the machine up properly to use these more advanced features. It can be easily done yourself though. Here is a link to a Technical Manual which describes how the machine works and what the options are.

Here is an example of how the ResMed machine operates when set up with the AutoRamp and EPR at 3 on Ramp Only. You can see the pressure cycling (Mask Pressure) during the going to sleep mode, and then stop cycling when you fall asleep. You can also see how the pressure self adjusts during the night to events.