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First post - initial pressure setting advice needed - Printable Version

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First post - initial pressure setting advice needed - Cuppa - 04-04-2017

G'day all, I'm a new CPAP user. Sleep test revealed an AHI of 43.1  Have been on a hire machine for 8 nights now with highest nightly AHI being 2.3 & lowest being 0.57. Machine is a Resmed 10 Autoset & I've used Sleepy head on my Mac to follow what is going on. Precribed pressure is 8 & the Resmed is set on this fixed pressure. It did have the ramp set on auto, & the auto on set to on, but I didn't like either of these so have turned them both off.

Today I ordered a Devilbiss Intellipap 2 Autoadjust from one of the US suppliers online, (only older models sold here in Australia) primarily because of it's relatively low power consumption, this being important as I expect to be travelling long term with it, running it from solar & batteries. I think I need to use humidification as I'm finding the most comfortable setting on the Resmed is Humidity at 5 & the heated tube at 28 degrees.C.   At 4 I got a dry throat, & at 5  & 27deg.C I got condensation waking me in the early hours. My hope is that Devibiss' pulse dose humidification will be effective without hammering my batteries too hard.

It's a pity that Sleepyhead & the Intellipap 2 don't yet play nicely together, I'm keeping my fingers crossed that this will change.

Anyway - to the purpose of my post...... When the Intellipap 2 arrives I'm keen to try it out on auto & am seeking advice as to pressure settings. My thinking is to have the lowest setting at the lowest the machine will go (4?) & the highest to be my prescribed pressure of 8.  Hoping to find a good balance between therapeutically effective & minimising power consumption.
It appears that folk often set their upper pressure a bit higher than their prescribed pressure, but I'm uncertain why this might be, or indeed whether it is a good thing to do. The sleep technician where I had my studies done said she wasn't keen on auto machines because folk usually set the pressures too high, & that this correlated with an increase in central apneas. My very limited experience appeared to back that up. The machine hire place inadvertantly set the Resmed at a fixed pressure of 10 rather than 8, & so for the first night I had it on 10. That night I had one obstructive apnea & the rest were centrals (Clear airway events). Although a huge improvement overall my sleep study had shown no centrals at all. On subsequent nights I have reduced the pressure to 8 & although still getting a few centrals, the number has reduced.  (Both in quantity & length) - most apneas, obstructive & central now show between 10 & 20 seconds. Longest in sleep study was 81 seconds.

I welcome any thoughts on auto machine pressure settings, & would also like to take the opportunity just to say thanks. I've spent a bit of time reading posts on this forum & have found it very useful.

Cheers
Cuppa


RE: First post - justMongo - 04-04-2017

Welcome

G'Day from the left coast of the US. You'll probably feel starved for air if you set a starting pressure of 4. Your numbers on your ResMed machine sound pretty good. I would suggest bracketing the 8 cm-water pressure you use now. The max pressure isn't such a concern as the machine should not advance pressure higher than you require to treat OSA. The machine should not advance on detection of a CSA. If it were I, I would set a min/max pressure window of 7 to 10 cm-water. You may have to bump the 7 min up to 8.


RE: First post - Crimson Nape - 04-04-2017

Hello Cuppa,  Welcome
The following is a basic rule-of-thumb that seems to be a very good starting point:
First, the 4cm setting can cause the feeling of being starved for air.  For this reason most people report that an initial setting point of around 7cm eliminates this feeling and is closer to your prescribed range.  The upper limit is generally set to be about 2cm above your prescribed pressure to catch the stray events that may occur.  Our sleep patterns vary and an auto setting will allow the CPAP to adjust to provide the best and least possible pressure to overcome a sleep apnea event.  Finally, The narrowing of the pressure range seems to aid the CPAP's algorithm in providing a better and faster response to your needs.    

I hope this may give you the insight you are seeking.


RE: First post - initial pressure setting advice needed - PaulaO2 - 04-04-2017

I updated the subject line of your post to better reflect the question(s) so you can get the answers you need.


RE: First post - initial pressure setting advice needed - trish6hundred - 04-04-2017

Hi Cuppa,
WELCUME! to the forum.!
Good luck to you as you continue your CPAP therapy.


RE: First post - initial pressure setting advice needed - Cuppa - 04-04-2017

Thanks for the welcome & the advice.  Thanks