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Wrong hose setting for VPAP machine
#1
Does anyone wonder what happens if you use the wrong hose setting for a VPAP machine? I am using a Resmed VPAP Auto in S mode (straight bilevel). I have "Easy Breathe" set to on which makes the transitions very smooth-almost undetectable. Took a trip and used the slimline hose while on the trip since it takes up less room in the luggage. When I got back, I went back to using the standard hose. I noticed that the transition from EPAP to IPAP and back was very harsh. My FFM was doing push-ups on my face, which is difficult as tight as the mask is for my pressure and face.

I thought that maybe I had inadvertantly turned "Easy Breathe" off. Looked at the settings and it was still set to on but I noticed that I had forgotten to change the hose setting back from the slimline setting I had used while traveling. Oh-jeez Set it back to standard and the system went back to the very smooth transitions.

Just thought someone might like to know. Huh

Best Regards,

PaytonA
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#2
(10-01-2014, 10:50 AM)PaytonA Wrote: My FFM was doing push-ups on my face, which is difficult as tight as the mask is for my pressure and face.

Hmmmm..... Think P10. Resistance is futile.

Interesting observation about the hose though.
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#3
It believe the hose type is important to the FOT algorithm.
(Wave velocity in the tubing)

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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#4
(10-01-2014, 01:22 PM)justMongo Wrote: It believe the hose type is important to the FOT algorithm.
(Wave velocity in the tubing)

I think that you are absolutely right, Mongo. I think that it is also important to several other things like pressure at the mask, actual flow, sensing of flow limitations, and probably a few other things I have not thought of right offhand. I was limiting my observations to a thing that is easily detectable so that if someone starts having their mask start jumping up and down they might look at the hose type setting as well as other things.

Best Regards,

PaytonA
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#5
I always wondered what would happen if the hose was set wrong. Now I know. Thanks!
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#6
(10-01-2014, 10:50 AM)PaytonA Wrote: When I got back, I went back to using the standard hose. I noticed that the transition from EPAP to IPAP and back was very harsh. My FFM was doing push-ups on my face, which is difficult as tight as the mask is for my pressure and face.

I thought that maybe I had inadvertantly turned "Easy Breathe" off. Looked at the settings and it was still set to on but I noticed that I had forgotten to change the hose setting back from the slimline setting I had used while traveling. Oh-jeez Set it back to standard and the system went back to the very smooth transitions.

Hi PaytonA,

The Slimline hose has greater resistance (needs greater pressure drop across it to pass the same amount of hose airflow), especially for high rates of airflow.

There is no pressure lost across the hose (no drop in pressure across the hose) when there is no airflow through it (like for example if we remove the mask and use the palm of our hand to completely stop all airflow). But when lots of airflow (moving air) is occurring, the pressure lost across Slimline will be significantly greater than the pressure which would be lost across a standard hose.

The hose airflow will be increasingly higher when we use high mask pressures because Intentional Leak will be increasingly higher as the mask pressure increases.

When the machine is set for Slimline, in order to compensate for the greater pressure lost across Slimline, the machine delivers higher pressure into the hose, especially when the Intentional Leak is high because the mask pressure is high. The machine delivers even higher pressure into the hose when additional (unintended) leak is detected.

So, I think the primary effect of the machine mistakenly being set for Slimline is the pressure at the mask will be higher than than it should be, and also the PS (Pressure Support, the difference in pressure between EPAP and IPAP) at the mask will also be raised higher than it should be.

PS will be incorrectly raised higher, especially if there is high airflow through the hose, because the machine will be assuming the pressure dropped across Slimline will be higher during IPAP (when hose airflow will be higher because Intentional Leak and perhaps unintentional leak, too, will be higher) than during EPAP.

Membership in the Advisory Member group should not be understood as in any way implying medical expertise or qualification for advising Sleep Apnea patients concerning their treatment. The Advisory Member group provides advice and suggestions to Apnea Board administrators and staff on matters concerning Apnea Board operation and administrative policies - not on matters concerning treatment for Sleep Apnea. I think it is now too late to change the name of the group but I think Voting Member group would perhaps have been a more descriptive name for the group.
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#7
I've always thought that the main consequence of wrong hose (or mask) settings will be on the measurement and dynamic pressure functions, not on static pressure.

By "dynamic," I mean things like EPR, Flex, bilevel, and maintaining a constant pressure through the breathing cycle as you inhale and exhale.

By measurement, I mean things like apnea detection and categorization such as central vs. obstructive.
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#8
(10-03-2014, 04:51 AM)archangle Wrote: I've always thought that the main consequence of wrong hose (or mask) settings will be on the measurement and dynamic pressure functions, not on static pressure.
I agree.

Quote:By "dynamic," I mean things like EPR, Flex, bilevel, and maintaining a constant pressure through the breathing cycle as you inhale and exhale.
The pressure drop from mask vent flow and average breathe (Tidal Volume) would be rather small. The dynamic flow you speak of would be in the high rate flow data where we see + and - 100 LPM airflow.
Then the pressure drop might be a factor.

If I were more ambitious I would model this... but, I think it not of value.

Quote:By measurement, I mean things like apnea detection and categorization such as central vs. obstructive.
That would be due to wave velocity in the tube.
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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#9
(10-03-2014, 07:44 AM)justMongo Wrote:
Quote:By "dynamic," I mean things like EPR, Flex, bilevel, and maintaining a constant pressure through the breathing cycle as you inhale and exhale.
The pressure drop from mask vent flow and average breathe (Tidal Volume) would be rather small. The dynamic flow you speak of would be in the high rate flow data where we see + and - 100 LPM airflow.
Then the pressure drop might be a factor.

The high rate Flow data shows only a portion of the total airflow through the hose, only the portion which is the tidal Flow being breathed (positive Flow is the rate of air entering our airway and negative Flow is the rate of air exiting our airway).

The hose also carries the total leak (intentional plus unintentional). And both components of the total leak are probably larger during IPAP, if the pressure is higher during IPAP because bilevel or EPR is being used.

And note that the airflow from the machine into the hose is usually always positive; its maximum is during IPAP (when hose airflow is sum of total leaks plus the positive peak of tidal Flow), and its minimum is during EPAP (when hose airflow is total leaks minus the magnitude of the negative peak of the tidal Flow).

Membership in the Advisory Member group should not be understood as in any way implying medical expertise or qualification for advising Sleep Apnea patients concerning their treatment. The Advisory Member group provides advice and suggestions to Apnea Board administrators and staff on matters concerning Apnea Board operation and administrative policies - not on matters concerning treatment for Sleep Apnea. I think it is now too late to change the name of the group but I think Voting Member group would perhaps have been a more descriptive name for the group.
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