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General Discussion on any topic relating to CPAP and/or Sleep Apnea.
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KatieW
 
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Re: ResMed S9 and AHI 0.0 - Look Bob no hands!

Postby KatieW on Tue Mar 16, 2010 3:53 pm

Dave, thanks for posting your graphs. I printed them out, then taped them together, so they all lined up on one page. Then I drew pencil lines from the points where your Pressure went up, up and down the page. If you're clever with computer graphics, I'm sure you could do this more accurately.

Anyway, this is the pattern I saw, which leads to more questions. I know there's no way of knowing, but I'm wondering if this is what could have happened--or please tell me if I'm totally off base.

At approx. 23:15, the pressure went from 10 to 12.2. The Leak at that moment was low, but the Flow Limitation dipped to the mid-point of the graph--so the pressure increase seemed to be in response to the Flow Limitation. And since there are no apneas or hypopneas, this was effective.

There was a slight increase in snore at that same moment, but still in the low range. I'm wondering if you happened to roll over onto your back, which initiated the snore? And maybe this small the snore was enough to cause the Flow Limitation?

The Minute Ventilation was steady, but went up soon after the pressure went up, as did the Flow. And this is because the pressure increased, took care of the flow limitation, so normal breathing resumed? Seems to be a good argument for using apap mode.

At the other points where Pressure increased, there was a similar pattern. Fascinating stuff. What do you, or others think?

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Additional Comments: ResScan 3.10, PapCap Plus, Hozzer, AEIO Headrest Nasal Pillows
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dave21
 
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Re: ResMed S9 and AHI 0.0 - Look Bob no hands!

Postby dave21 on Tue Mar 16, 2010 4:23 pm

KatieW wrote:Dave, thanks for posting your graphs. I printed them out, then taped them together, so they all lined up on one page. Then I drew pencil lines from the points where your Pressure went up, up and down the page. If you're clever with computer graphics, I'm sure you could do this more accurately.

Thanks Katie for taking an interest! I have updated the image in the post above to show red lines now so that should make it easier but also re-included it here as I now see it's scrolled onto a new page :)

Image

KatieW wrote:At approx. 23:15, the pressure went from 10 to 12.2. The Leak at that moment was low, but the Flow Limitation dipped to the mid-point of the graph--so the pressure increase seemed to be in response to the Flow Limitation. And since there are no apneas or hypopneas, this was effective.

Completely agree with you here. As there was a massive change in flow limitation I would say an Apnea was about to start and was averted by the 2cm increase in pressure that the auto mode detected. The was a very slight increase in the snore but there was also an increased leak (not major) going from about 1.00 L/min to 5.00 L/min.

KatieW wrote:There was a slight increase in snore at that same moment, but still in the low range. I'm wondering if you happened to roll over onto your back, which initiated the snore? And maybe this small the snore was enough to cause the Flow Limitation?

The increase leak rate (although small) from 1.00 L/min to 5.00 L/min could be that I rolled onto my back or that I re-adjusted my mask at that point - or even buried my head more into the pillow to make the mask come away slightly.

KatieW wrote:The Minute Ventilation was steady, but went up soon after the pressure went up, as did the Flow. And this is because the pressure increased, took care of the flow limitation, so normal breathing resumed? Seems to be a good argument for using apap mode.

The Minute Ventilation was pretty steady it peaked up once from 10.00 L/min to 20.00 L/min then back down to 10.00 L/min for a short while then back up again to spike when the pressure increased by 2cm.

I've updated the graph so now you see red vertical lines on. The first two I've placed just before the increase in pressure so you can see these more easily. I've also marked on the graph the 3rd red line around 1:15am where again the pressure increased due to flow limitation and I responded adequately to prevent an apnea, and also the 4th bold red line around 4am is where I saw a massive leak increase (this was sustained and increasing for 15 mins), probably due to rolling over but interestingly the leak sorted itself out but likewise the pressure didn't increase and was actually on the decrease at this point. So the S9 is very capable of telling the difference between a flow limitation (obstructive event) and a leak so it doesn't increase the pressure.

My only concern here would be that if there is significant leak rate (and we might possibly say that it's not significant enough), then there's less oxygen coming through the mask which in turn could mean that there's not enough pressure which could lead to a collapse in the upper airway and result in the start of one or more apneas. Just a thought...

Now one other comment is that because I've been studying the graphs over the past couple of weeks and making minute changes tweaking my Ramp, Min and Max over the past week, if I had these left at my previous settings this almost certainly would have brought on one or several Apneas and sent my AHI up above 0.0. With the changes I made this seems to have kept them at bay for the night and gave me a better night sleep. :D

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KatieW
 
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Re: ResMed S9 and AHI 0.0 - Look Bob no hands!

Postby KatieW on Tue Mar 16, 2010 7:25 pm

... and also the 4th bold red line around 4am is where I saw a massive leak increase (this was sustained and increasing for 15 mins), probably due to rolling over but interestingly the leak sorted itself out but likewise the pressure didn't increase and was actually on the decrease at this point. So the S9 is very capable of telling the difference between a flow limitation (obstructive event) and a leak so it doesn't increase the pressure.


That's very interesting...I've often read here about apap's "running away with leaks". I wonder if the S9 in different in that regard.

My only concern here would be that if there is significant leak rate (and we might possibly say that it's not significant enough), then there's less oxygen coming through the mask which in turn could mean that there's not enough pressure which could lead to a collapse in the upper airway and result in the start of one or more apneas. Just a thought...


Unless it responds to the Flow Limitation 1st?

Now one other comment is that because I've been studying the graphs over the past couple of weeks and making minute changes tweaking my Ramp, Min and Max over the past week, if I had these left at my previous settings this almost certainly would have brought on one or several Apneas and sent my AHI up above 0.0. With the changes I made this seems to have kept them at bay for the night and gave me a better night sleep. :D


Yes, you seem to have found your best range and settings. :D Thank you for this very interesting post.

_________________
Mask: Mirage Activa™ LT Nasal CPAP Mask with Headgear
Humidifier: S9™ Series H5i™ Heated Humidifier with Climate Control
Additional Comments: ResScan 3.10, PapCap Plus, Hozzer, AEIO Headrest Nasal Pillows
KatieW

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