BeadyEl wrote:A little over ten years ago I had my first sleep study. The results were: no significant sleep apnea.
I believe that it is very likely that the amount of measurable sleep apnea in a person varies each night such that it is undetectable many nights at least in the early days.
As well the “Golden Standard” test cannot actually measure how you sleep in your own home in your own bed since it is administered far away from there in a very public environment in a very invasive manner. After spending all that money and expense you still have no idea how you sleep in your own home in your own bed night after night. You do however know how you sleep during one or perhaps a couple of very expensive night(s) in a public place with all kinds of wires attached and your future depending upon the results.
BeadyEl wrote:However, the reason I had the study done was because I was suffering from insomnia, and it was ruining my life . . . No, this insomnia would wait until I was just dozing off, peaceful and happy – and then suddenly I would snap awake, my pulse racing. For no apparent reason. Over and over and over and over . . . All night . . . Night after night... Then I got my home machine – and discovered that, far from enriching my sleep, it's stealing it away. In fact, it prods me awake nearly every time my breathing rhythm changes (you know, like you do when you're first dozing off?) Other times it blows my mouth open – again, usually just moments after I doze off.
I have come to believe that CPAP intolerance for those with insomnia is strongly related to three things. High respiratory control loop gain, low arousal threshold, and expiratory pressure intolerance (EPI).
In a recent study it was determined that some 36% of those with Obstructive Sleep Apnea (OSA) have high respiratory control loop gain[1]. They tend to overshoot when trying to correct for too little O2 or too much CO2 – or the vice versa of each.
This means that there will be inappropriate air hunger which translates in to greatly increased respiratory effort which results in excessive arousals.
They also determined that some 37% had a low arousal threshold. I am suspicious that this is why both you and I have trouble dealing with the crazy “clear airway sensing / pacing” air pressure pulses from our “modern” CPAP machines. With those added to the already high levels of noise and vibration shooting up the tube to our masks it is a wonder anyone can get any sleep at all.
As well getting used to CPAP can be complicated by expiratory pressure intolerance (EPI)”
“During expiration, the discomfort from standard pressurized airflow seems to trigger an anxiety response that the insomnia patient cannot overcome; whereas with the use of auto-bilevel devices, including ASV, the patient’s comfort level is noticeably higher.
In these cases, the subjective and objective finding is expiratory pressure intolerance (EPI).”[2]
I have been watching the discussion concerning how Expiratory Pressure Relief (EPR) or BiPap often help those who have problems getting used to CPAP but recently I had an experience which moved this from theory to understanding. In my efforts to lessen the affects of the crazy “clear airway sensing / pacing” air pressure pulses from my machine I plumbed into the circuit some compressible air space. Well that does indeed slow the rise/fall times of the pressure pulses but it also lessens the effects of my expriatory air meeting the CPAP fan recently spun up to facilitate inspiration. The feel is very much more like breathing into normal air. It is so nice! The vibration and noise in the tube are also considerably less as well.
BeadyEl wrote:...So – any cause for hope?
Yes. Today I learned how to access the secret menu that lets me turn down the pressure. It's the only thing I've heard or read that has calmed me in the least. Maybe I can still salvage the situation. Just find a place where the air doesn't quite blow my doors off. I'll do what I can to adjust - with a goal of returning to a setting of 17 - but damn it, during the adjustment period the infernal machine can bloody well meet me halfway for a while. Plus, it's Friday – tomorrow I can sleep in as much as I want.
So the titration done in the lab (over a single night or half night at great expense and inconvenience with considerable financial and emotional pressure) did not work too well? No surprise here!
My last in home “titration” lasted over 60 days and found a pressure which worked for many months. Only a few small changes have been made since. I believe in using lifestyle to manage how the machine works for me but will change pressure if that is not enough.
BeadyEl wrote:Also, I've requested a chin strap, which is on its way. Once I have that in hand, I'll try the higher settings again.
And if those don't work, a conversation like this may be ahead:
“So Doc, I guess there's something we should have discussed earlier: any treatment plan that hinges me 'toughing out' a wholly unpredictable number of sleepless nights – is just plain out of the question. For most people it'd be an inconvenience, for me it's a first-class ticket to gibbering madness. I literally can't take it.
So, what else you got?”
Doctors have people beating down the doors to get any help they can. I would not place my expectations from doctors very high. They indeed do not have to try.
[1] Danny J. Eckert, David P. White, Amy S. Jordan, Atul Malhotra, and Andrew Wellman "Defining Phenotypic Causes of Obstructive Sleep Apnea. Identification of Novel Therapeutic Targets", American Journal of Respiratory and Critical Care Medicine, Vol. 188, No. 8 (2013), pp. 996-1004. doi: 10.1164/rccm.201303-0448OC
[2]
http://www.sleepreviewmag.com/2014/01/a ... a-and-sdb/