sleeptech

I think you must have misunderstood. I said that CPAP USUALLY relieves oedema because it does, but that doesn't mean that it can't be causing it in your case. Your situation may be unusual but that doesn't mean that CPAP is not causing your problem. I certainly have no interest in shutting down discussion. If you learn anything more about what is happening please let us know because I'm sure there are plenty of people, not least of all myself, who would be interested in hearing about it.

I totally agree (in case that didn't come across in my previous post).

Not in my experience. Usually the doctor prescribes the pressure and leaves the rest of the details up to the supplier. It can take weeks or months of trial and error before finding out whether and auto may be called for. Suppliers are always keen to use an auto whenever they can get away with it because they make more money from the sale. Most doctors don't really know much detail about how various machines and modes work - that's what we techs are for. Also, retailers and, in many cases, doctors only get their information about CPAP machines and how they work from the manufacturers, and the manufacturers just tell them it always works fine with no problems because they want to sell more expensive units. I know this sounds a bit cynical, but unfortunately I see these things happen all too often. One of the reasons I post on this site is in the hope that, by better educating patients, more people will get the best and most appropriate treatment rather than being sold a machine that costs 3 times as much when they don't need it.

A good question. APAP (or Auto as we often call it) doe not treat your OSA any better than fixed pressure CPAP. In fact, because it has to see obstruction before it can respond to it and increase the pressure, it can be slightly worse (although for most people it's just fine). Also, it can be fooled by some things into increasing your pressure way more than necessary. If you have twitchy legs, for example, your auto will think that this is obstruction and increase your pressure, but because it doesn't stop the legs twitching it will keep on increasing the pressure until it maxes out. So for this and other reasons auto doesn't work for everyone, but it is fine for most. The benefit of an auto is that it keeps the pressure as low as possible for as long as possible. This can make it more comfortable in some cases. That is all well and good, but an auto costs about 2 - 3 times as much as fixed pressure CPAP, which is a lot of money for a possible slight increase in comfort. Of the thousands of patients I treat every year, maybe 1 or 2 will actually need auto to tolerate CPAP. The rest all manage just fine with normal CPAP (all of which have ramps, humidifiers and other features to help). So use an auto by all means if you think it's helpful and worth it, just bear in mind that you'll be paying a LOT more for that increased comfort, and that most people don't need it. If possible, see if you can try for yourself before purchase. Or possibly rent before buying if that's not too expensive (although rental can often be ludicrously expensive in an effort to force you into a purchase).

I can't imagine why CPAP pressure would have anything to do with back pain, nor have I ever heard of it happening. However, what could be happening is that the increase of pressure has stabilised your breathing better which has lead to your sleep being less disturbed. This could mean that you are moving a lot less in your sleep which is thus causing the back pain. This could still be true if it was just REM sleep that is improved because in REM sleep most of your muscles are super relaxed to stop you acting out your dreams. It's a bit like you body anaesthetising itself. If you had not been having solid REM and now you are, causing you to be more still, then this might have an effect. I'm really just guessing here. Unfortunately I have no great ideas for fixing it. Just be careful about medicating for it, because if you take muscle relaxants for your back they may also relax your airway making your OSA worse, and then you need more than 17 cmH2O to keep you breathing properly.

I use ResScan all the time (and hate it because it is unstable and unreliable, but that's neither here nor there). As Wiredgeorge said, the main statistic is the AHI. This measures the number of changes in breathing that occurred per hour of operation (not sleep mind you because the machine doesn't know when you are sleeping). Generally speaking, anything 5 or below is good. The hours of use is also important. The most useful figure is average usage per night (this is what is used for assessing compliance). ResScan also supplies median usage, which is a bit obscure and not terribly useful. Mask leak can also be handy, which ResScan can show as median leak, 95% leak and max leak. median leak is similar to the average level and should probably be below about 15, but this is rather variable depending on the patient and the mask used. Max leak level is a bit useless because it is the maximum leak level recorded at any point in the period of the report, which may only last for 2 seconds and is therefore not relevant. 95% leak is more useful because it is the highest leak rate reached if you leave out the worst 5%. This is handy because, combined with the median leak rate, you can tell if fit is usually good but gets worse in patches or if it is good all the time.

ResScan is highly configurable and can display all sorts of statistics and graphs. Most of it is totally useless. Stick to the basics. Also remember that the data should always be taken in the context of the patient's real world experiences. If there is a high leak rate but the patient is happy, the AHI is low and their symptoms are well controlled, why bother about it? Likewise, just because the leak reading is great that doesn't mean you can simply ignore the patient telling you that their mask leak is bothering them.

As usual, Wiredgeorge is on the ball.

Your ResMed machine should be able to detect the central apnoeas if they develop, so you're probably fine. I'm glad it's helpful for you. For most people EPR is probably harmless, it's just that there are risks, and the number of people for whom it is a problem, albeit the minority, is still pretty significant. Even a small proportion of sufferers from a condition as common as OSA can be tens of thousands of people (possibly even hundreds). This is exacerbated by the fact that the manufacturers tell everyone that it's completely harmless and everyone should use it, so most CPAP machines have it turned on by default. As usual, proper education is the key here, along with healthcare professionals who are prepared to put in all of the work required to do the job properly.

Yes, an EPR of one should drop the pressure by approximately 1 cmH2O. EPR of 2 drops the pressure by 2 cmH2O and so on. Sorry that explanation was confusing.

With regard to asthma being related to OSA - it is true that they both involve narrowed airways. However, asthma (as I understand it - this is not my field) involves a narrowing of the bronchioles which are small tubes that spread out throughout your lungs connecting the alveoli to the trachea. OSA is a collapse of the airway at the back of your throat, a completely different part of your airway. Therefore I doubt that they are directly connected. However, because both hinder your breathing, it would seem possible that they could interact. For example, if your asthma was narrowing your bronchioles due to some environmental cause (like pollen), then you add OSA on top your oxygen levels could start lower and drop lower. This may also cause an increased arousal response. In short, the symptoms of your your OSA would get worse. This doesn't mean that the 2 are connected, they just affect the same area.

I can also confirm that there is no surgical procedure demonstrated repeatedly effective for the treatment of OSA. While there are plenty of doctors who will perform surgery for OSA, there is not a surgery which is officially approved as an effective treatment. In all of the cases of surgery which I have seen or heard about, there is a very low rate of success, and those surgeries which are successful often only reduced the severity of OSA, eg from an AHI of 100 to 50, which is still a big problem. Also, if they are successful to any degree, there is a high chance of surgeries reverting so that you wind up as bad as or worse than before. Add to this the fact that most surgeries are very painful, have a long post-operative recovery time and have a high rate of post-operative infection, and the picture is pretty bleak. every doctor I know (including all the good ones) won't touch surgery with a barge pole for the reasons given above. As stated before, I am not a doctor, and medical science changes rapidly, so an effective surgery may be developed. Just be very wary if your doctor starts talking surgery because they often don't mention, or just plain don't know, the things I wrote above. Do your research and know exactly what you are getting into.

In relation to your question about exercise mdavis, I concur that you should start with CPAP. It will only help increase your ability to exercise. If you can lose weight and thus cure your OSA you can stop the CPAP. Also, it is very likely that you can rent a machine in the short term (we do that where I work).

CPAP use usually relieves oedema, rather than making it worse. If your sleep specialist cannot come up with any better answers, I'd seek the opinion of a cardiologist. It may be a sign of something else going wrong. I can assure you that it's almost certainly nothing to do with your humidifier.