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Minimum pressure on ResMed S9 Autoset

Posted: Thu Sep 20, 2012 4:10 am
by wellwood
I have my ResMed S9 Autoset set between 4cm and 7cm. My next day's pressure graphs show that it stays at 4cm until an event occurs, when it rises to 7cm (and hopefully does its job). It will then drop to around the 6.2 - 6.6cm pressure (but never lower thereon).
I need to turn the power off, then on again to get the pressure back to the 4cm mark, which is more comfortable.
Surely the CPAP machine should default back to the minimum setting (4cm) when "all is clear". Any thoughts would be appreciated.
PS..I am a newbie from Australia and am overjoyed to have your forum to learn the many and varied aspects of CPAP therapy.

Re: Minimum pressure on ResMed S9 Autoset

Posted: Thu Sep 20, 2012 5:52 am
by apneawho
After an event, it will maintain a pressure that represses another event. It has internal algorithms and sensors that determine this. It make take a pressure of around 6 to keep your otherwise collapsed airway open. My magic numerber is 14.2. Each person's anatomy is different.

Re: Minimum pressure on ResMed S9 Autoset

Posted: Thu Sep 20, 2012 6:05 am
by Pugsy
wellwood wrote:Surely the CPAP machine should default back to the minimum setting (4cm) when "all is clear".
APAPs don't increase in the blink of an eye and they don't decrease in a blink of an eye either. If you wake up and pressure of 6 is showing and you don't like it then you don't really have a choice except a quick restart to drop the pressure down to starting point again. Some machines have a ramp button separate from the on/off button but the ResMed doesn't.

I don't know how long you have been on the machine but eventually we do get used to the pressure and eventually that 6 cm pressure won't seem so awful for you. If you are seeing it stay at 6 all night...then there is a reason the machine is staying at 6 or whatever. The APAPs respond to event precursors...warning signs that a collapse of the airway is imminent.
Things like snores or flow limitations. If you wake up and stay awake long enough the machine will drop down to 4 cm again but it does it in gradual steps down. If you are asleep and see it stay at 6..then the machine is doing its job because it senses the need for that pressure.

Re: Minimum pressure on ResMed S9 Autoset

Posted: Thu Sep 20, 2012 8:33 pm
by KEQ5
4-7 is a very low (and rather narrow) range.

You may just need to get used to the pressure and/or play around with the EPR setting (try it at 1 or 2cm) to make it more comfortable.

If the machine had to go up to 6.5-7.0 in order to stop your events and the limit is 7.0, then you're going to need to look at your charts and see whether it's always bumping up against the 7.0 limit and whether you're still seeing a lot of OAs at the 7.0 pressure.

Re: Minimum pressure on ResMed S9 Autoset

Posted: Thu Sep 20, 2012 11:20 pm
by wellwood
Many thanks to apneawho, Pugsy and KEQ5 for your informative replies.
After studying my graphs, I see that my maximum pressure is indeed bumping along the 7cm mark for a lot of the night (previously set at 4.0 min-7.0 max) and EPR set to OFF.
For tonight's journey into sleepsville, I have set the pressure at 5.0 min and 9.0 max, and turned the EPR to position 1.
My main problem with the increased pressure is that I get a bubble of air in my mouth every now and again (causing a 'blowing bubble effect'), even when I am just lying in bed watching TV, with my mouth firmly closed and breathing regularly.
Will let you know how I perform tonight, thanks again...

Re: Minimum pressure on ResMed S9 Autoset

Posted: Fri Sep 21, 2012 7:24 am
by robysue
wellwood wrote: My main problem with the increased pressure is that I get a bubble of air in my mouth every now and again (causing a 'blowing bubble effect'), even when I am just lying in bed watching TV, with my mouth firmly closed and breathing regularly.
Will let you know how I perform tonight, thanks again...
If the air in your mouth problem starts turning into an air in your stomach problem, you may want to consider backing the pressure back down to your original range of 4-7 if your AHI < 5 at that range and you were not seeing significant clustering of events occurring when the pressure was at the max.

While it goes against conventional wisdom here at cpaptalk, there's nothing automatically "wrong" with allowing an APAP to hit its max pressure setting (frequently) if your max setting is enough to control your apnea---as in your overall AHI < 5 and you are NOT seeing significant clusters of events when you are at maximum pressure. In other words, for a few people, very minor snoring and flow limitations can cause an auto machine to increase pressure to the point where it triggers aerophagia and/or spontaneous arousals caused by discomfort. And if you're one of these people (I am), increasing the max pressure beyond what you strictly need to control the apneas and hypopneas can lead to diminishing returns: The higher max pressure doesn't necessarily bring the AHI down any further, but it can increase restlessness and discomfort during the night, which then leads to less overall sleep and less high quality sleep, which leads to feeling lousy in the daytime.

Re: Minimum pressure on ResMed S9 Autoset

Posted: Sun Jul 07, 2013 12:30 pm
by luiggi
I just got my Resmed S9. When I turn it on a blast of air (like a leaf blower) comes out of the mask. The air pressure shows 4.0 . If I put the mask on I feel that my head is going to blow out. Is this normal?? When I was at the clinic the air started to come out very slow . Is there anything wrong with the equipment or ???

Re: Minimum pressure on ResMed S9 Autoset

Posted: Sun Jul 07, 2013 12:37 pm
by Wulfman...
luiggi wrote:I just got my Resmed S9. When I turn it on a blast of air (like a leaf blower) comes out of the mask. The air pressure shows 4.0 . If I put the mask on I feel that my head is going to blow out. Is this normal?? When I was at the clinic the air started to come out very slow . Is there anything wrong with the equipment or ???
Strap the mask on your face BEFORE you start the machine. Otherwise, it's going to do what you describe.


Den

.

Re: Minimum pressure on ResMed S9 Autoset

Posted: Sun Jul 07, 2013 2:04 pm
by Luiggi
I tried to start the resmed 9 with the mask on and the air continues to blow very hard without going down. I feel that my nose and my lungs are going to explote!!!. It only shows 6 cm.......What next ??? Thank you.....

Re: Minimum pressure on ResMed S9 Autoset

Posted: Sun Jul 07, 2013 5:55 pm
by DreamDiver
wellwood wrote:... My main problem with the increased pressure is that I get a bubble of air in my mouth every now and again (causing a 'blowing bubble effect'), even when I am just lying in bed watching TV, with my mouth firmly closed and breathing regularly. ...
If you're getting "chipmunk cheeks", and air is leaking out of your mouth, then you may be a mouth leaker, in which case you may want to try a full-face mask. (Some people like to try mouth taping - you can search this forum for taping.) Whether you elect to try the full face mask or try taping, a PapCap is a great addition to stop chipmunk cheeks. If you are getting air into your belly (aerophagia) causing painful belly aches and gassiness, then you may want to do as robysue suggests and reduce your settings back down so that you no longer experience aerophagia.

Re: Minimum pressure on ResMed S9 Autoset

Posted: Sun Jul 07, 2013 5:57 pm
by DreamDiver
Luiggi wrote:I tried to start the resmed 9 with the mask on and the air continues to blow very hard without going down. I feel that my nose and my lungs are going to explote!!!. It only shows 6 cm.......What next ??? Thank you.....
Hi Luiggi - Welcome. Why not become a member, fill out your equipment profile and allow us to learn more about what you're going through on a new thread for you?

Re: Minimum pressure on ResMed S9 Autoset

Posted: Sun Jul 07, 2013 6:21 pm
by billbolton
wellwood wrote:even when I am just lying in bed watching TV, with my mouth firmly closed and breathing regularly.
The scoring algorithms on any xPAP system only function effectively when you are asleep and breathing autonomously

Anytime you are awake, you will be breathing differently than when you are asleep, so whatever you experience while using xPAP while awake is no guide to what will occur will you when you are asleep.

Cheers,

Bill

Re: Minimum pressure on ResMed S9 Autoset

Posted: Sun Jul 07, 2013 6:22 pm
by Luiggi
Hi dreamdiver: I'm a member already.

Re: Minimum pressure on ResMed S9 Autoset

Posted: Sun Jul 07, 2013 6:46 pm
by DreamDiver
Luiggi wrote:Hi dreamdiver: I'm a member already.
Unfortunately, you are not logged in right now, and you have not yet posted while logged in with the name "Luiggi". Your name will then be bold, high-lighted and linked to your profile so we can learn more about your machine, mask and other stuff. (See image below comparing your avatar and mine.)
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If you see "Login" instead of "Logout [ Luiggi ]" you can be pretty sure you're not logged in on the computer you're using.
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