Auto CPAP Algorithm

[ping]

1. I have completed my sleep study(PSG and MLST). Study indicated I have AHI=6, MLST=6.5mins and O2 sat=94%. Doctor recommended Auto CPAP for a month to see I have OSA. I have using for about 2 weeks now.

2. The prescribed titration is 4 to 40 cmH2O. For the first few nights, the pressure went up to as high 11 cm after about 2 hr of sleep. And at this pressure and the noise was what I could take and I would be awake. I would reset and the cycle repeats. This went on couple more days. I then set the pressure Max to 8 cm and I could sleep longer and now I set the max to 9cm it seems ok for now. Plan to slowly increase the max pressure.

3. Looking at above, can it be deduced that I have OSA? Or is the CPAP suppose to automatically increase to some baseline pressure whether the user has OSA or not?

4. Hypothetically, if a person with no OSA, no respiratory problem were to use a Auto CPAP(set at 4-20cmH2O), would the pressure go up to above 10cm ?

5. At one time, I woke up after the pressure has gone above 10cm, I stayed awake and breath normally but the pressure remained above 10cm. Isn't it suppose to go down?

6. Appreciate very much if some of you folk can enlighten me

[El Pap]

I'd recommend that you fill out your equipment profile, so that we'll be able to give you better advice.

An APAP responds to the precursors to apnea like snoring and flow limitations, as well as to actual apneas and hypopneas, so it's difficult to say for certain that you definitely have OSA based solely on the information that your APAP increases. Looking at the data that the machine collects would be extremely useful in this regard. The machine will not increase pressure unless it sees events, although in someone with borderline OSA those events could be snoring and flow limitations that might not necessarily proceed to actual apneas and hypopneas w/o treatment.

The severity of sleep apnea and the pressure required to treat it have no relation to one another. Someone could have severe OSA that is resolved with CPAP at 6 cm/h2o, while someone else has mild OSA that requires 16 cm/h2o.

Pressure changes on APAP machines are made very gradually, which is why the pressure when you awoke remained high.

[apnez]

According to you description I assume that you have an APAP may be a Resmed Autoset II adjusted 4-20 cmH2O. How do you think you are going to have a clear picture if you "play" like that with the machine? If the machine goes to 11 this is because you NEED it, not for the "pleasure" of making "noise" and for the purpose of embarrassing you... By adjusting it to 8 you cancel the whole process. Sure you will have less noise but you will never know what are your real needs. Why do you think your doctor ordered a one month trial at a wide range? That is simply a long term and more precise titration than what you already got. Your doctor is not sure if you have OSA, this is the reason of his particular prescription. After a month he will analyze the figures and tell you. What you are doing is simply scrap the whole process. Simply just come back to those prescribed settings. Period.

This is what people mean when they say : "If you don't know what you are doing don't play with the machine!"

[ping]

I'd recommend that you fill out your equipment profile, so that we'll be able to give you better advice.

An APAP responds to the precursors to apnea like snoring and flow limitations, as well as to actual apneas and hypopneas, so it's difficult to say for certain that you definitely have OSA based solely on the information that your APAP increases. Looking at the data that the machine collects would be extremely useful in this regard. The machine will not increase pressure unless it sees events, although in someone with borderline OSA those events could be snoring and flow limitations that might not necessarily proceed to actual apneas and hypopneas w/o treatment.

The severity of sleep apnea and the pressure required to treat it have no relation to one another. Someone could have severe OSA that is resolved with CPAP at 6 cm/h2o, while someone else has mild OSA that requires 16 cm/h2o.

Pressure changes on APAP machines are made very gradually, which is why the pressure when you awoke remained high.

Thanks El Pap. That is what I know and thought it should be. But this machine I am having does not seemed to be doing so. What happened was I ended up with this brand of Auto CPAP from Germany for a month trial from the supplier when I really wanted was a Remstar which was out of stock at that time....That why I went around looking for more info on CPAP. I really did not intend play around with the setting precribed if it had been doing what it supposed do.

[timbalionguy]

You may also find you will get more 'used' to the machine if you raise your minumum pressure to, say, 6. Most people here report 'suffocating' at 4. As others said, if it is going to 11, it is probably because you need 11. Work on improving your mask fit so it is comfortable and leak-free at 11. 11 really isn't a super-high pressure, and if that is all you need long term, you are lucky. If 11 works out to be your 'titrated pressure', then your final range might work out to be 9-13.

Whatever you do, do it incrementally, and give things time to settle down. At least a week between pressure setting changes.