Newbie issues w Dreamstation Autopap

palerider wrote:

emmagoldman44 wrote:Palerider - those mask liners are definitely something I will check out, thanks.

they were a game changer for me when I was wearing a full face mask. the lady that runs padacheek.com is really nice and cares more about helping people than making a buck.

emmagoldman44 wrote:Here's my latest insight: one thing I couldn't understand is why I DID NOT have this problem with the PR System One. I mean, I didn't like the resistance against my exhale but I could live with it okay and go to sleep. Now I just discovered that tubing size affects the actual pressure coming out at the "patient end" of the tubing, and I am pretty sure that I had the larger size tubing, which according to the PR manual, brings down the actual pressure to 3.6 . So I used to have 3.6 actual pressure vs. 3. 8 for the smaller tubing that I now use with the Dreamstation.

there's a tubing setting. just make sure that it's appropriate for the tubing you're using. the machine adjusts pressure to compensate for the greater resistance in smaller tubing. if you use large tubing but have it set to slim, you'll end up with more pressure.

I bought a used machine, hooked up my hose, and thought it was defective, pressure seemed way too high, until I remembered I was using standard tubing but the default setting on the machine was for slim tubing... after changing that, it felt fine.

emmagoldman44 wrote:For me, as I feel the amount of air rushing out of the tube at 4 cm, I know it is more air than I would normally be inhaling as part of a resting breath....

this is a *common* mistake people make. they take the mask off, and there's all this huge amount of air blowing out of the mask, and they start freaking out. some engage in hyperbole about "gale force winds" "leaf blower" "blow the mask across the room" crap.

the *fact* is, the machine has a pressure sensor right at the outlet, it measures pressure typically in centimeters of water. ie, how much pressure it takes to push down that many centimeters of water. you can feel *exactly* how much pressure that is by sticking a straw in a glass of water, and blowing. four centimeters is slightly over 1/2 inch. so, stick a straw 1.5 inches in a glass of water, and blow.. if you got bubbles to come out, you've just blown harder than 4cm/h2o pressure.

now, as to that rush of air, like I said, the machine is set to create a specific pressure. pressure is the result of resistance to flow. when there's no resistance (or very little) like when your mask is off... the machine creates MORE flow, to try and get pressure. but there's no resistance, so the air just blows out, so the machine tries harder, spinning the fan faster, and faster, till it's at full speed, trying to make some pressure, pushing against nothing.... so you get a huge amount of flow with no pressure. it's like turning on the garden hose and letting all the water run out, it doesn't go very far, big flow, low pressure, but if you put your thumb over the end, the flow goes way down but the pressure goes up, and the water shoots a much longer distance.

as soon as you put your mask on, the machine senses the the increasing pressure, and slows the fan down. (it checks maybe a hundred times a second, maybe more, depending on the model.) it slows the fan down till there's only that very gentle 4cm/h2o of pressure, that you blew bubbles with. and none of it is blowing up your nose... where would it go? if it was actually blowing up your nose, you'd eventually explode! no, the air, and that gentle pressure, is just sitting there, until you do what you normally do, until you inhale, THEN air goes up your nose, into your lungs, giving you the oxygen you need to live. then you exhale and the air comes back out your nose, against that tiny bit of pressure... and flows out the vent holes in the mask.

emmagoldman44 wrote:So now, my main remaining issue is that weird burst of pressure that occasionally occurs at the end of inhalations. .

emmagoldman44 wrote:Hmm, using a larger tube setting is something I should definitely try. I appreciate your points about getting used to the pressure but, remember that I didn't have this problem at this same setting on my PR system one with the larger tube, and also, it has been 4 weeks now on my current machine and it hasn't gotten easier for me in the last few weeks. One factor in my low AHI success at a low pressure is probably that I additionally use a tongue retractor - I forget the brand name but it has the look of a pacifier and helps to keep my tongue out of the back of my throat. By itself however, it was inadequate.

m13l1n1 wrote:Sometimes this might have something to do with the mask you are using that blocks moving air. See if you have air escaping from mask when exhale or try different size mask might help.

m13l1n1 wrote:See if you have air escaping from mask when exhale ...