(05-17-2014, 01:44 PM)retired_guy Wrote: You might want to discuss this with your sleep docs, but I'm thinking you might want to slowly, very slowly begin adjusting the max pressures downward. To begin with maybe something like a min of 11 and a max of 18.
(05-17-2014, 01:29 PM)readyforsleep Wrote: Thanks for your ideas. Not sure I understand. Are you saying that
Just because the autopap can go up to 20, it doesn't necessarily mean
I need a pressure of 20? I never even considered that possibility. I do have
a followup visit with the doctor in June. I'll see what she suggests then. She
made a point of telling me not to change anything before my next visit. Wonder
(05-17-2014, 12:31 PM)retired_guy Wrote: ... A lower leak rate might mean the machine would not have to work so hard and consequently not run quite as high a pressure which makes the leak rate go up.
I think it is a common misconception that high unintentional Leak will cause the machine to increase the mask pressure. Even a moderately high unintentional Leak of 20 or 30, for example, does not cause the machine to raise the mask pressure. In the presence of Leak the machine's algorithms increase the airflow the machine is producing but only enough to compensate for the unintentional mask leaking, so as to maintain the machine's target mask pressure.
It is important, though, for the hose type to be set correctly to inform the machine what diameter and length of hose is being used. As long as it knows the hose type, it's algorithm for calculating the pressure loss through the hose will be accurate and therefore it will will be able to accurately maintaim the mask pressure at its target pressure, especially if the leaking is steady and doesn't fluctuate quickly. (However, the more quickly the leaking is varying, the less accurate the machine's treatment will be.)
That the pressure is maxing out is not, in itself, any reason to consider lowering the Max Pressure setting.
Reasons to consider lowering the Max Pressure setting would include excessive centrals if seen in the machine's reported data to begin mostly at high pressures (some people see excessive centrals at high pressures but most do not), inner ear problems caused by high pressures (hearing loss, ringing or dizziness), air and mucus from nasal cavity leaking from tear ducts after being pushed into eye cavity (full face mask may help prevent this), excessive swallowing of air causing uncomfortable bloating, or the pressure being too high for a new PAPer, making it impossible to sleep or start treatment. Or recent nasal surgery (normally CPAP treatment would be stopped, per surgeon's orders, for weeks or longer after surgery). Or a previous medical history of spontaneous pneumothorax (collapsed lung, just from coughing or other normal activity).
As retired_guy recommended, it is important to keep Leak low. Many members have reported that when Leaks have been reduced their treatment has become much more effective.
Your doctor wants to see several weeks of data with the machine on wide settings, so he/she can form an informed opinion on how to proceed.
The machine is raising the mask pressure in order to minimize snore, Flow Limitation (upper airway partial collapse/resistance), hypopneas and obstructive apneas. In other words, obstructive events are causing the machine to raise its pressure to 20, which is very high, especially since you have turned off EPR (for good reason, in your case).
One reason to consider getting a bi-level machine is those generally allow a higher setting for Max Pressure, usually a max of 25 instead of 20. But in your case, because you may be susceptible to centrals, you may find that above a certain pressure your centrals will increase, so do keep a lookout for that and keep your doctor informed.
Regarding centrals, one small study reported that about 15% of CPAP patients experienced high rates of CPAP-induced central apneas. In about half of this 15%, after several months or longer of therapy the frequency of centrals gradually decreased to an acceptably small amount. I think the other half of the 15%, the cases which did not go away on their own, probably could have been treated well using Adaptive Servo Ventilation (ASV) therapy using an ASV machine, which is a more expensive machine than a standard bi-level machine.
The most common reason to change to a bi-level machine is to make high pressures more comfortable by increasing the pressure difference between inhale and exhale (especially when the pressures get up to 15 or higher), but this might not apply in your case because this may cause excessive amount of central apneas to occur.
In your case, perhaps best would be to try to lower the amount of pressure your machine needs to use. Rather than lowering the Max Pressure setting (that is, unless you need to because of one of the reasons listed above for retired_guy), I suggest you take precautions to stay off your back while sleeping.
Obstructive Sleep Apnea is usually highly positional, with the worst position usually being flat on your back.
Some put on a small knapsack when they are ready to sleep. I wear a snug teeshirt with a tennis ball in a pocket sewn right between my shoulder blades, so that when I roll onto my back while asleep I wake up just enough to roll over some more, to my other side.