languageusa wrote:I had a comprehensive overnight polysomnography in June 2012 and was diagnosed with OSA:AHI was 62.5, including hypopneas and central apneas. During the CPAP titration in August 2012, at a pressure of 13cmH20, the events per hour decreased to 0. The 7-day initial period of the CPAP therapy was based on an auto-pressure of 10-16, and the 95% pressure was 11.4; during this initial period my average AHI level was 4.1, and the periodic breathing was 2.3% So the pressure of 12 was established for my constant pressure. All the nights that followed (7 weeks of so today), with the pressure of 12, my AHI levels became uncontrollable: I was getting all kind of numbers within the range of 9-26 (once even 35), with the average of 18. Not a singe time did I approach the AHI levels of my one-week initial CPAP period. Btw, my periodic breathing index has also increased, it is now between 5-7%. My current CPAP info looks like it belongs to a totally different person, unless the machine is malfunctioning…
I think the issue you are dealing with is called unstable breathing. The constant pressure of CPAP tends to make one breath a bit more which tends to wash out CO2 and, for whatever reason, seems to generate even more air hunger. Eventually you wake up enough to shut the over breathing down for a time only to begin another cycle.languageusa wrote:I have two separate questions.
1. What are possible causes for this dramatic increase of the AHI after only one week of almost ideal AHI numbers that were, in turn, totally consistent with the CPAP titration results? My doc says “I don’t know”. And he is adding: “I have been in practice for over 30 years, and never did I see such AHI fluctuations.”
The result is an airway inflamed by too much air volume and a body whose circulation and metabolism are frustrated by hypocapnea.
Things I have noticed contribute to this:
Stress! This ratchets up the central nervous system, tends us toward breathing more, and creates more inflammation in the body which tends us toward more apnea.
Lack of exercise. Aerobic exercise and especially (if you are enough in shape for it) interval training tend to stave this off in my experience.
Violent media. I guess you could call this virtual stress.
Change of the seasons. I have tracked this in my own experience and seen it in some data gathered by others. I do not know why, perhaps the body is under a kind of stress getting used to a different temperature.
CPAP therapy. I really do not understand why doctors think that our bodies do not change after the titration. If the therapy is successful, you will heal, your need for pressure will therefore change. Not a hard one for me.
Your doctor is correct telling you that you are having trouble with the pressure. Indeed, I do believe that the reaction of your body to the pressure (hypocapnic breathing, unstable breathing) does indeed do more harm than the OSA itself. His call is not unreasonable.languageusa wrote:2. During the last several days my doc tried auto pressure setting of 9-15, the 95% pressure was 15 (top), but the AHI was still 15. That was just for one day -- I could not tolerate the pressure. He then tried, at my request, a constant pressure of 13. The AHI number was bad again, and I was having some difficulties tolerating that pressure as well. He said then, with irritation, that he had spent a lot of time looking at my data (?!), I am not tolerating the pressure and that he was going to remove me from the CPAP machine and instead put me on oxygen. This troubles me immensely. That would mean I am entering the dangerous zone of an untreated severe sleep apnea again with no hope for recovery. I know the forum members are not doctors, but -- any thoughts, ideas, etc.? Another type of machine, may be?
Thanks for replying to this message.
I think using this could help you develop some better breathing reflexes and so stabilize your breathing:
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3014237/
I am also suspicious you would do better at less pressure. If I were you I would:
Raise the head of my bed a few inches. This may well reduce your need for pressure. I use a couple of concrete blocks from a building supply store – less than five dollars for a pair. For the cost, why not? Tell your doctor that it may help prevent GERD, Rostral Fluid Shift, and that Robert Dawkins, PhD, MPH in his book “How to Tolerate CPAP Therapy for Your Sleep Apnea” says that raising the head of your bed may lower the pressure needed to eliminate AHI.
See if my doctor is willing to read the article. He may go for a better machine. Sometimes they will actually go for the extended re-breathing space. I under the watchful eye of my doctor did use this one year to get though a high stress time with very good results. I recommend it from experience. In my case it provided a way to get though a tough time. In your case it may provide a way to give you time to develop some breathing reflexes while using CPAP. CPAP consistently tests out as yielding the least arousals and the best long term prospects. I have found that true.
Do what I can to reduce stress!!!
Start toward walking 10,000 steps a day (the recommended amount). Just start – maybe 1000 steps every other day. Just start. Eventually do some aerobically, and when well trained, some as interval training. I have found a treadmill a wise investment indeed!
Consider doing some breathing retraining such as pulse oximeter guided breathing or Buteyko breathing. After a year of doing a mix of both my CPAP pressure need was reduced by about 50%! This time of year I am under a great deal of stress. My pulse oximeter is constantly at my side and used daily. I do believe you can re-train your breathing reflexes and do recommend this from my own experience. It does take a lot of time and effort.
Practice breathing very quietly and gently with the machine during the day. Make a point to quiet your breathing as you go to sleep with the machine. If you wake up breathing heavy hit the ramp button and go for quiet breathing. I find it helps to put a pause between exhale and inhale.
I hope you do find good answers soon!
Todzo
