New sleep study new questions (fixed pressure vs. APAP)

[ColoradoMom]

My son recentally had a titration/ MSLT study. I though I was finally understanding all of this, but my son's new sleep study has led to many new questions. 

A brief history. My son's previous sleep study showed mild/ moderate OSA and low baseline oxygen saturation. His AHI was 13.9 (6.9 central apneas 7 obstructive hypopneas). My son also has a couple of other sleep disorders: circadian rhythm disorder, and possibly REM behavior disorder.
Further Cardio/ Pulmonary testing following the sleep study has shown asthma, autonomic dysfunction, and sinus tachycardia (the cardiologist is not concerned about the tachycardia). My son started CPAP in late November at a fixed pressure of 5. At a pressure of 5 his AHI ranged from about 4-9, so the Pulmonoligist raised the pressure to 6. At fixed 6 his AHi has ranged from .8-9, at , his AHI probably averages about 5. 
The reason my son's sleep doctor did not do the titraiton study immediately following his sleep apnea diagnosis was that she had concerns about hypoxia, REM behavior disorder, and narcolepsy, and she wanted to be able to rule out OSA as the cause of any other possible disorders.
Anyway my son had his tiration study last week. I don't have the official results, but the sleep tech broke the rules and filled me in. 

She told me that he had numerous arousals that will be classified as spontaneous, but she believes they were actually caused by UARS (apparently my local lab does not score UARS).
She told me his apnea was "treated" at a pressure of 6, but his oxygen saturation average was under 90 at 6. She continued to increase the pressure and his oxygen saturation went up to 95 at a pressure of 9. The tech advised me to take advantage of my son's APAP machine and reset it to the APAP mode. Her boss walked in right as I was about to ask her what to set the machine to, so I missed the opportunity to ask her how to set the machine. 
My son's sleep doctor is great, but I don't want to discuss the conversation the sleep tech had with me with his doc because I don't want to get the tech into trouble.

So my questions for you why would my son's doctor set his APAP machine at a fixed pressure? Are there any drawbacks to alternating pressures? The tirtation study found the optimum pressure to be 9, if I set his machine to APAP what range would you recommend?

[DeepBreathing]

Hi ColoradoMom.

How old is your son? I ask because paediatric treatment for a small child might be very different from what would be offered to an older teenager / young adult.

The fact that half his AHI was central apnea, together with the other issues, leads me to be very cautious about offering detailed advice. This may be best referred to your medical team.

In relation to fixed v auto pressure, the general consensus among users is that an auto pressure allows you to run at a lower average pressure, with the machine only increasing pressure when needed. The auto machine can also adjust as needed as you grow older, if your health changes, whether you're sleeping on your back or side and so on.

The contrary view is that the changes caused by an auto machine can in themselves disturb your sleep. There are certainly some members here who find that a fixed pressure is more comfortable and has better efficacy. Some / many sleep docs seem to have an inbuilt preference for fixed pressure and/or a suspicion of auto pressure. They seem to think that they just need to have a titration study to determine a single fixed pressure which will suit you forever. Or at least until they need to make some more money out of you. Never mind that a titration study is almost guaranteed to give you a false reading due to the strange environment and the fact you're wired up to 19 probes and electrodes.

The other issue is that with central apnea there is a possibility that APAP will make it worse. Doesn't always happen, but it is certainly something to look out for.

When next talking to the doc, I suggest you raise the following issues:

1. Your son has a high proportion of central apnea - is CPAP / APAP the most suitable treatment?

2. Is a single pressure setting likely to treat him optimally or would an auto setting be better? (Don't need to tell him where you got the idea).

3. How is this apnea treatment going to interact with his other conditions?

[ardenum]

I can't really offer any advice, but maybe you can help me. How did you find out your son had sleep apnea? What symptoms made the doctor send him to do a study in the first place?
Did you do a tilt table for the autonomic part?

Thanks!

[Walla Walla]

One thing you can do is download the Software Sleepyhead. It gives you detailed data and charts so you can see whats going on with the treatment. The Dreamstation should have a SD card already installed under the first lid on the right side. Using a card reader you can transfer the data from your machine to the computer. Links for downloading Sleepyhead as well as a guide to reading it are below.

[Ron AKA]

So my questions for you why would my son's doctor set his APAP machine at a fixed pressure? Are there any drawbacks to alternating pressures? The tirtation study found the optimum pressure to be 9, if I set his machine to APAP what range would you recommend?

There certainly are a lot of complicating conditions to consider here, and most are well beyond my level of understanding. I'm an engineer, not a doctor. So, I would encourage you to continue working with your doctor on the complete picture. That left aside here are my thoughts on your questions.

The history of the apnea treatment business is that the cheapest option, which is a fixed pressure machine, is tried first. This can be driven by insurance company demands or the medical system trying to control costs, or the patient not wanting to spend the $$ if they are on the hook to pay. When you have a fixed pressure machine it is almost always going to be a bit of a compromise, so that is why a titration test is quite important. If the patient treatment is not successful with a fixed pressure machine then they move to an auto pressure next. In short it is money and tradition. 

Now with the cost of auto machines coming lower the line is becoming blurred between the treatment options. You appear to have the auto machine already, and it is a good question as to why it is not being used. With the other medical conditions they may be concerned about high and low pressures it could use. But they could easily set a narrow range of say a max of 10 cm and a min of 6 cm, and do a follow up to see how that works. They may be concerned about central apneas which may be aggravated by high pressures, and the lower fixed was considered safer.

Again this all said, if you want to continue on your own, it would seem there would be no harm in setting a minimum at 5 where you have been and the maximum at 6 where you have been, and then monitor the results using SleepyHead. The pressures will be limited but you will see what is happening. The links to download and use SleepyHead are at the bottom of my post. If you post them here you will get comments on what can be done. But the general process would be to start with that narrow band, and then slowly increase the maximum and watch for any increase in central apneas, CA's in SleepyHead. Alternately you could post some past daily detail screens from history which should be in your machine with the fixed pressure and will be downloaded to SleepyHead when you install and update it. They would be helpful as well. 

Hope that helps some,

[Walla Walla]

For the time being I's stick to what the Doctor ordered. There's a lot going on here and we're not privy to all the details. It wouldn't hurt to post a chart from sleepyhead here but I'd hold off on any changes until you have some data built up from the settings the Doctor issued.

There's a lot of second guessing of Doctors that goes on here. Sometimes justified, sometimes not. But I would tend to take a Doctors advice over the Tech's advice until you have proof the Doctor isn't cutting it.

[ardenum]

Theres alot going on so everyones afraid to give any specific tips, especially without any charts. On a side note I can say, i have dysautonomia (POTS mixed with orthostatic hypotension) and occasional tachycardia. After 2 years of CPAP all of the above got better. I used to have tachycardia daily but now its maybe once or twice a week. I also tolerate standing for longer periods of time then before.

It is in my experience higher pressures work well for the tachycardia. I believe its similar thing going on like with the Valsalva maneuver, where you hold your breath and strain, creating pressure, to cancel the tachycardia. I assume higher CPAP pressure works like that. I used to get alot of tachycardia when going to bed, with the higher pressures it went away really fast.

I also have asthma, albeit the allergic one.

[Mogy]

Hi ColoradoMom,
Higher pressure usually reduces the obstructive apneas but may increase the central apneas. Until a person sees the data, the proportion of centrals, hypopneas and obstructive, it is difficult to make any recommendations.
If your son's Dreamstation came with an SD card there is already a wealth of information on that card. If you can work with Sleepyhead, the posters here will be able to give you a better understanding of what is going on.
The reason that your doctor is starting with a low pressure and then increasing it a bit may be due to the central apneas. Over time a person may get used to that pressure and the centrals will reduce.
If you do decide to increase pressure go very slow.
Are you at a high altitude? At higher altitudes, more people have central apneas. If you go high enough, 100% of people have central apneas.

[ColoradoMom]

Thank you so much for your detailed replies DeepBreathing, Walla Walla, Ron AKA, and Mogy!
My son is 16, he is still considered pediatric but he is nearly an adult. I think that there is a possibility that the fact that we live at 7000 feet may be a factor in my son's centrals. My son has actually had 3 sleep studies in the last year. Initially we were looking at a year long wait to get my son in with a pediatric sleep doctor in Colorado so we ended up traveling out of state for his first sleep study. His first study was done at about sea level, he was diagnosed with mild OSA and was simply prescribed decongestants and nasal spray. He had no central events at the low elevation sleep study. My son's neurologist recommended doing another sleep study at a higher elevation, and as she suspected his AHI was higher and his oxygen saturations were considerably lower at the elevation we live at. I was concerned about the centrals, but the CPAP has decreased them. His central numbers typically range from 1-6 over the entire night with CPAP. The sleep tech told me that my son had centrals during his titration study, but said not to worry about them because they were the result of movements during his sleep. My son's sleep doctor is great, but his next appointment with her is not until July. The local facility where my son had his study does not read pediatric studies, everything is sent up to Denver to be read. I anticipate that my son's doctor will order a pressure increase once the results come in, but it took a full month to get the results of his last sleep study so I expect that it will likely be a month or so until any changes are ordered. The main reason I was considering changing the pressure myself was the dramatic improvement the higher pressure had on his oxygen saturation. I have a recording oximeter and monitor his nighttime oxygen levels occasionally. With CPAP the desaturations have dramatically decreased, but his mean oxygen level is generally about 90. I don't understand why increasing the CPAP pressure after his AHI numbers were good raised his mean oxygen saturation from 90 to 95, so I am hesitant to make changes myself since I really don't understand what is going on. 

I think the best course of action is to wait on APAP until discussing it with the doctor. I'm still considering increasing the pressure to a fixed 9 on my own. I have sleepy head, I'm at a different computer right now, but I'll post some charts this evening. Is there much risk in raising the pressure myself? I figure that if more centrals show up I can bump the pressure back down. In the grand scheme of things I guess a month isn't that long to wait, but I hate for his oxygen levels to remain low when there may be a remedy. Thank you once again for the many helpful replies!

[SarcasticDave94]

Hi ColoradoMom and welcome to Apnea Board.

On adjusting the pressure, if I've followed accurately, is a fixed 6 right now. If correct, and if this were me, I would consider going 1 point up and review the results of several days even a weeks worth of data. I would not just jump to 6 from 9. I would probably also explore APAP.

Now, note I said if this were me. For you and your son, I more agree with Walla Walla as I would suggest waiting for the doc in this case. Get his/her input as DeepBreathing outlined. Then judge for yourself if this doc gives appropriate and reliable medical advice by viewing the results of CPAP/APAP use of at least 1 week. If you don't trust the docs advice, and if the doc then doesn't offer additional assistance you agree with, then that is when to consider taking on adjustments yourself. And if at that point, you don't trust the docs advice, it's probably time to shop for a different doc too. All IMO