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AirFit P10 vent blocked?
#61
RE: AirFit P10 vent blocked?
(04-14-2015, 02:08 PM)PaytonA Wrote:
(04-14-2015, 11:11 AM)Sleeprider Wrote: The PRS1 leak graphs show two lines. One is the total leak, and the second is the "unintentional leak". It stays at zero unless a higher leak rate is detected. The machine determines the baseline "design" leak pretty accurately.

I think that Archangle is correct - that Sleepyhead calculates the unintentional leak rate for PRS1 machines. The machine only provides total leak rate.

How would the PRS1 determine the "design" leak rate?

Best Regards,

PaytonA

PRS1 machines don't even attempt to determine the intentional leak rate. If you look at Encore, it only shows the total leak rate.

SleepyHead determines the mask leak rate or "intentional leak rate" for PRS1 machines based on something like an average of the minimum leak rate at a particular pressure. It works pretty well, but isn't foolproof. A mask with some holes plugged or extra holes will show up as a "normal" intentional leak/vent rate.

BTW, even the ResMed machines don't determine the "designed" leak rate. They determine a "base" leak rate. If your mask has a few vent holes plugged, or leaks too much due to having the holes drilled wrong, the ResMed machine will be happy with that and will use the actual vent/leak rate as the "intentional" leak rate. It works in part by assuming that things like leaks around the mask or mouth leaks will vary over time, whereas the vent rate designed into the mask will always be the same at the same pressure.

One of the things that really annoys me about the ResMed way of doing it is that if you do something like block your exhale vent with your pillow or your arm, there is no indication of this in your data because they clip the "intentional" leak data at zero. The PRS1 machines will show a drop in the total leak rate and you'll know you have a problem.
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#62
RE: AirFit P10 vent blocked?
(04-14-2015, 04:16 PM)WSHenry Wrote: I'm not sure if the unintentional leak rate shown in SleepyHead is calculated by the PRS1 or by the software.

By the software. Jedimark discussed this online while he was developing the software, It was on the cpapcough web site. 9/30/2014

jedimark on cpapcough Wrote:The mask settings were never actually connected to anything.. they was a note in the preferences pages saying it didn't work.. It wasn't used by the unintentional leaks calculations..

Unintentional leaks work via a analysing Total Leaks to find a baseline for each pressure, and subtracting the generated baseline from the total leaks.. (Encore software and ResMed machines work in a similar way)

My current code has got a bug that still needs fixing, where consistently bad leaks causes it to screw it up it's baseline calculations.

To properly solve this, I need to make it look at more history data and include some failsafes to sense when the algorithm fails to get a valid baseline."

If you are having problems with too much massive leaks, you can now turn off the extra plot on PRS1 in the new right click menu and just work off the machine detected total leaks for now.

Someone posted a description of the ResMed intentional leak calculation somewhere and it was actually considerably more complicated, but it was still based off of the actual airflow data, not information on the masks. It was something like checking something at the peak inhale and peak exhale and doing some sort of analysis of the differences. It's done in the machine itself. I don't have the link handy, sorry.

As best as I can tell, Encore doesn't calculate intentional leak, but maybe there's something there I haven't noticed or some option I'm missing.

Get the free OSCAR CPAP software here.
Useful links.
Click here for information on the main alternative to CPAP.
If it's midnight and a DME tells you it's dark outside, go and check it yourself.
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#63
RE: AirFit P10 vent blocked?
For the machine to determine the "design" leak rate for any calculations would be seriously uninformed engineering. Looking up the design vent rate and comparing it against actual is informative but may well just lead to a number of other questions which many users may not be equipped to determine the answer.

All of this discussion just brought up another question in my mind. The question springs solely from my curiosity and does not carry with it any facetiousness or sarcasm.
How does the PRS1 determine total leak rate??

Best Regards,

PaytonA

Admin Note:
PaytonA passed away in September 2017
Click HERE to read his Memorial Thread

~ Rest in Peace ~
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#64
RE: AirFit P10 vent blocked?
I've had my CPAP machine for nearly 3 years. There is no place to get information about pressures. I can get my AHI average, but that's it. My issue is the same as what started this whole thread. The mesh vents are plugged. When I plug the end of the mask tube, there is no air coming out of the vents. I think they have been that way since I got the mask. The problem is that when I exhale, the air does not leave through the vents, rather I'm rebreathing it all night long. First was waking up feeling like I was suffocating, then had headaches in the morning. Finally had chest pain and shortness of breath in the night, and complete daytime exhaustion. One night back with my old SwiftFX and I'm good as new. There is something wrong with the mesh vents as several others on this thread have indicated. Like one of the first people on this thread, my mesh vents look like there is some kind of plastic coating. I have tried cleaning with a brush. I'm just trying to figure out if it is a common problem, or whether it is worth trying a new AirFit P10. I do love how it fits and feels, but I've got to be able to breathe at night.
(06-09-2014, 02:13 PM)scott1965 Wrote: My vents seem to have some kind of coating on them preventing air from escaping.

I can disconnect the mask tube from from the heated line tube, plug the hole at the end of the mask tube, put on the mask and blow air into it and almost no air moves out of the mask-next to nothing comes from the exhalation ports.

When disconnected from the machine and the hose end plugged I need to blow hard enough to blow up a balloon. It was not like this when I got it.

Any one else have this problem or a solution?

Thanks.

Mine too. Did you end up getting a new P10? I love the fit of the mask, but gotta be able to breathe.
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#65
RE: AirFit P10 vent blocked?
I also could not use the P10 because it was so hard to exhale.
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#66
RE: AirFit P10 vent blocked?
Car40, the difficulty with exhaling is not related to the rare problem of venting being inadequate, but is because you're exhaling against CPAP pressure of 10. You would probably feel the same resistance with all nasal pillow solutions.

Peyton, the machine measures flow as well as pressure. There is a constant exhaust that occurs. In the absence of leaks, this amount of flow is relatively constant, and the machine uses that as the mask intentional leak rate. On PRS1 machines, the total leak flow is shown (intentional+unintentional), as well as the machine's best guess of the unintentional leak, which stays near zero unless leaks or mouth breathing occur. Resmed machines only show this unintentional leak line. On a PRS1 machine, the leak line with an Airfit P10 mask looks like this when leaks are minimal:

[Image: benYFYgl.png]

With a little more leakage, it might look like this:

[Image: Mz9zhbEl.png]
Sleeprider
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INFORMATION ON APNEA BOARD FORUMS OR ON APNEABOARD.COM SHOULD NOT BE CONSIDERED AS MEDICAL ADVICE. ALWAYS SEEK THE ADVICE OF A PHYSICIAN BEFORE SEEKING TREATMENT FOR MEDICAL CONDITIONS, INCLUDING SLEEP APNEA. INFORMATION POSTED ON THE APNEA BOARD WEB SITE AND FORUMS ARE PERSONAL OPINION ONLY AND NOT NECESSARILY A STATEMENT OF FACT.
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#67
RE: AirFit P10 vent blocked?
(04-15-2015, 12:01 PM)PaytonA Wrote: All of this discussion just brought up another question in my mind. The question springs solely from my curiosity and does not carry with it any facetiousness or sarcasm.
How does the PRS1 determine total leak rate??

It has a sensor in the blower that measures what I'll call the "blower flow rate." i.e. the air flow in the blower itself, which includes patient flow rates plus total leaks.

The average blower flow rate is the total leak rate.

Note that the "flow rate" graph is actually the blower flow rate unit minus some form of average flow rate. It's how the machine estimates the flow rate into your body from the flow rate at the blower.

The PRS1 SE, DS150, and Plus models don't measure flow at all.

Get the free OSCAR CPAP software here.
Useful links.
Click here for information on the main alternative to CPAP.
If it's midnight and a DME tells you it's dark outside, go and check it yourself.
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#68
RE: AirFit P10 vent blocked?
Makes sense. Thanks

Best Regards,

PaytonA

Admin Note:
PaytonA passed away in September 2017
Click HERE to read his Memorial Thread

~ Rest in Peace ~
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#69
RE: AirFit P10 vent blocked?
Getting back on topic, because the PRS1 460, 560, 760 etc show total leak rate, you KNOW that the mask is working correctly . The graphs I show above indicate a constant leak rate of about 30 liters which is far higher than the respiratory rate. This ensures purging of CO2. For those concerned about mask malfunctions, look at the total flow and leak line. I believe the resmed machines only indicate leaks that are above the intentional leak/vent threshold, so they may not indicate this important piece of information.
Sleeprider
Apnea Board Moderator
www.ApneaBoard.com

____________________________________________
Download OSCAR Software
Soft Cervical Collar
Optimizing Therapy
Organize your OSCAR Charts
Attaching Files
Mask Primer
How To Deal With Equipment Supplier


INFORMATION ON APNEA BOARD FORUMS OR ON APNEABOARD.COM SHOULD NOT BE CONSIDERED AS MEDICAL ADVICE. ALWAYS SEEK THE ADVICE OF A PHYSICIAN BEFORE SEEKING TREATMENT FOR MEDICAL CONDITIONS, INCLUDING SLEEP APNEA. INFORMATION POSTED ON THE APNEA BOARD WEB SITE AND FORUMS ARE PERSONAL OPINION ONLY AND NOT NECESSARILY A STATEMENT OF FACT.
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#70
RE: AirFit P10 vent blocked?
(04-16-2015, 09:39 AM)Sleeprider Wrote: Getting back on topic, because the PRS1 460, 560, 760 etc show total leak rate, you KNOW that the mask is working correctly . The graphs I show above indicate a constant leak rate of about 30 liters which is far higher than the respiratory rate. This ensures purging of CO2. For those concerned about mask malfunctions, look at the total flow and leak line. I believe the resmed machines only indicate leaks that are above the intentional leak/vent threshold, so they may not indicate this important piece of information.

I am sorry but I am having a hard time following your logic. Assuming a leak rate of 30 liters per minute, how does that correlate with your respiratory rate which is number of breaths per minute?

I think that you might have meant minute ventilation instead of respiratory rate. Assuming 10 liters per minute ventilation with 30 liters per minute total leak rate, what does that signify? For a FFM and some nasal masks, is 30 l/min enough air going through the mask to sufficiently dilute CO2? For some nasal masks and, I think, all nasal pillows this air does not even go through the mask but only through the hose.

With a Resmed machine it is easy enough to come up with an estimate of total leak. Just add the measured leak rate to the vent rate at that pressure and voila, you have total leak.

Best Regards,

PaytonA

Admin Note:
PaytonA passed away in September 2017
Click HERE to read his Memorial Thread

~ Rest in Peace ~
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