[Diagnosis] Awakened to strange inhalation problem

[PaBlum]

G'day,

I have severe OSA. Uncorrected, my AHI is about 51!

I've been a CPAP user for many years. For the past 4 weeks, I've been using a Dreamstation Auto BiPAP with ResMed Quatro Air (full face) mask. For the 5 years prior to that, I was using a ResMed Autoset S8 CPAP. The problem that I am about to discuss started with this machine change. Same mask used with both machines.

The S8 went to a max pressure of 20. I was hitting the ceiling many nights. Since CPAPs don't go beyond 20, a BiPAP seemed like a natural and my ENT agreed.

Before I talk about "the problem", I notice that my pressure readings are lower with the PR than the ResMed. Don't know whether it is calibrated differently (I've never had the calibration checked) or because it is a BiPAP or because the PR responds slower.

Now for "the problem". Every few (2-4) nights, I'd awaken finding myself inhaling heavily and the sides of the mask caving in, seeming to indicate that not enough air is being delivered. (Does I need more air because I am inhaling heavily or am I breathing heavily because I don't have enough air?).

Before you ask: there isn't any rainout blocking the tubing and the tubing is not crimped or twisted.

The problem is fixed by reaching over and cycling the power switch off, then on. It is as if the internal app needed to be relaunched. Unfortunately, I am now awakened and if it is close to the morning, as it was last night, I won't be able to fall asleep again.

Normally, nothing unusual is seen in my chart, just the interruption. Last night I couldn't fall back to sleep so the chart reflects that. And normally my AHI is under five, with some exceptions.

Attached is my overall stats and last night. Any suggestions? If tweaking won't help, perhaps the machine is faulty. Thanks, in advance, for any advice.

Paul

[ShaunBlake]

PaBlum, I'm not familiar with your machine so not sure this will help: what you're describing is what I experience when the power goes off.  (I use a nasal pillow mask, so it doesn't cave in, but I sure feel that I'm in a vacuum!)  Obviously your power hasn't failed since the machine is still recording, so I suspect a problem with the machine.  How many hours on it?  Need to discuss with your DME provider a repair or replacement.

[PaBlum]

Thanks for your reply. The machine is a new machine, 4 weeks old. It isn't a power problem for the following reasons:
1) Some air is being pumped through it, just not enough
2) I have a backup generator that kicks in after the power is out for > 30 seconds
3) My bedside clock is still lit
4) The problem goes away by hitting the machine power switch off, then on again.

A bad machine is always a possibility. Don't know how hard it would be to convince the DME of that. So, I'd like someone knowledgable of proper Auto BiPAP settings to take a look at mine to see if it is set properly before I call the DME.

Paul

[Sleeprider]

PaBlum, I have both a Philips and Resmed machine, so maybe I can shed some light on this. The Philips machines in auto mode (both CPAP and BiPAP) are much slower to respond to flow limitations and apnea precursors than Resmed (Autosets and Vauto). It's built into the algorithm and the only solution is to use higher minimum pressure in the Philips. FWIW, I am much more comfortable on the Resmed Aircurve 10 Vauto than the Philips Respironics BiPAP Auto, and experience a consistently lower AHI. The Philips has assumed a backup role for me, and for the few times I have had problems with the Resmed, I was glad to have it.

Let's talk about your chart a bit. With your current settings, EPAP min 10, IPAP max 24 and PS 2.0 to 8.0, you don't have to wait very long for the first cluster of OA to occur, and you can see the pressure response is reactive, not proactive. Again at 00:50, the machine is far behind the curve, and the apnea cluster continues until the machine reaches EPAP 15.0. Pressure drops fast until just after 02:00 when it hits 10.0 EPAP and you have another OA cluster followed by a pressure increase that leaves you with sporadic OA and FL for the next few hours. At the time of your therapy break you are at about the maximum PS of 8.0 with pressures of 20/12, and I think this rather high PS is what gave you the impression the machine needed reset and was doing funky things with your mask.

If you can't get a Vauto, then let's make your BiPAP auto better. I think you need EPAP min 13.0 (equal to your median here), and IPAP max can stay at 24.0. I'd like to see PS min at 4.0 and PS max at 5.0 to help resolve the flow limits and hypopnea without going over the top. If the obstructive clusters continue, a soft cervical collar or similar positional therapy may be needed. If you compare the median and 90/95% pressures on your current Dreamstation with the actual pressure median and 90% pressure from the S8, I suspect you will find the S8 was giving you similar pressure, but not dropping out when you needed it. Remember it is EPAP that supports the airway against obstructive apnea, and I seriously doubt your CPAP had pressures under 13 that were suitable for you. Also, your pressure support maximum is way too high for someone moving from CPAP and that does not have a real need for 8-cm pressure support. I think if we narrow the settings as outlined here, and limit the PS to 4.0, you will be more comfortable and the weird disruptive behavior of the machine should go away.

[PaBlum]

Thank you! I'll give it a try and report back.
Paul

[sheepless]

I've never been a fanboy of anything or anyone before but it's impossible not to marvel at sleeprider's broad knowledge and lucid analyses, explanations and recommendations.

[Sleeprider]

I've never been a fanboy of anything or anyone before but it's impossible not to marvel at sleeprider's broad knowledge and lucid analyses, explanations and recommendations.

Thank you! I'm humbled by the compliment. There are some problems that present themselves very clearly on the forum like this one, and I just kind of get in the "zone".  I hope it helps.

[PaBlum]

Suggested changes were made.

I awoke at 3 am to find my inhalations restricted. Not to the point that the mask was caving in like it was before, but it felt like that my air delivery was less than I needed so I worked harder to breathe in. I fixed that by cycling the power switch off/on.

I lay in bed for a while and must have fallen asleep at some point. I attached last nights graph. It clearly shows the power cycle and it seems that there are clear airway apneas just before that. The AHI is less than last night and I do feel more awake.

So, thanks for the analysis and suggestions. Please take a look and see if further adjustments can be made. I'm on U.S. Medicare and do not know whether I can trade the machine in.

TIA,
PaBlum

[Sleeprider]

Medicare stipulates that your machine be warranted by the approved provider for at least 2-years, and perhaps 3-years (not sure). I'm pretty sure if you contact the provider where you got the machine, they can tell you for certain what your warranty status is. A broken or malfunctioned machine under Medicare may be replaced prior to the 5-year replacement interval if it determined to be unrepairable. Medicare usually requires rental of CPAP equipment for 13 months and pays 80% of the cost under Part B. If you have owned the equipment for less time than that, it may still be under a rental agreement and the DME should support replacement or repair easily.

We are not certain if your machine is malfunctioning. The behavior ocurred near the maximum set pressure and during a cluster of central apnea. Your machine does not graph mask pressure, so we only know what it is reporting as pressure output. I think if you will make a closeup graph of the time just after 03:00 we can see what is going on in the apnea events, and see if there is flow-limited breathing or just apnea events. To zoom in, just click on the flow-rate graph repeatedly until you have about a 2-minute period so we can clearly see the wave-form. I included instructions on how to do this in the Organizing Your Chart wiki linked in my signature.

[PaBlum]

I'll take a shot at it. Actually 2 shots, both attached. Thanks, again. PaBlum