Increasing My Hose Length to 10ft.

This is in response to a reply I made in another post - I thought it would be better to not hijack that post esp. if others had additional comments or replies.

My comment was
- "oh forgot to mention when you use that 10ft hose you WILL have a loss of pressure too. So when you see changes in your chart, you will now whats going on. Be interesting to see if RT tells you about it."

Maybe I should have been clearer - on a forum like this it is a challenge to understand everyone's background and life experience. The full post is here-
viewtopic.php?f=1&t=41831&p=367936#p367936

Maybe I should have said if your snores and AHI suddenly improve but you feel strangely like your pre-cpap days the 10ft hose could have added to your problems.

Increasing My Hose Length to 10ft. My experience -
A little background first:
Awhile ago while using my M series bipap auto w/HH, I monitored my data daily while keeping a log on how I felt, my sleep postition, mask, stats, and changes I made. My pressure and numbers remained relatively stable at 18/15 with an AHI of <1. I think I feel best when my AHI is less than 1 and can tell when it is NOT.

I added an FP HC150 humidifer and later a 10ft hose.

Then my RT gave me an Activa nasal mask to try. While I liked the mask, I noticed I began to feel like the pre-cpap days but my AHI remained <1 - sometimes zero. Of course I tried to understand why the change.
When I put all the pieces together what I came up with was:
The machine has the sensors.
I kept the integrated HH = volume.
The HC150 has a 2ft hose plus the added volume.
The 10ft. hose.
The Activa mask had another 18in hose - something my other mask didn't have.
I think this was just enuff to make my machine insenstive to many events and caused a pressure drop over the increased (resistance) volume.

I removed the extra hose from the Activa but eventually reduced the length of my 10ft hose to 8ft too. My AHI improved again.

My rational was like in plumbing or electronics an increased length (volume) requires more and more push to get where you want it to go. And may not sense some events.

Some folks my never even realize they have a problem and may just think with an AHI of zero they are on top of the world. Others (straight cpap) may have increased their pressure to compensate without ever knowing why. Others still may not have the added volumes with the integrated HH, the HC150, or the extra 18in. at the mask end.

YMMV

So it is safe to assume that most xPAP machines have been calibrated for the std 6ft hose?

The way I understand it is that a longer hose doesn't decrease the pressure, it just takes more air to make the same pressure. Since there is greater distance and more air involved to do the same thing, the system may not detect it correctly. Does that kinda summarize what you are saying?

IN the clinical menu on my Resmed S8 Autoset one of the settings is for the length of hose so I assume the machine knows what it needs to do if I should ever want to increase the length of the hose

brucelegs wrote:IN the clinical menu on my Resmed S8 Autoset one of the settings is for the length of hose so I assume the machine knows what it needs to do if I should ever want to increase the length of the hose

Same with my Intellipap. If you are concerned about excessive pressure drop with a long hose, you can verify the delivered pressure with a manometer. Cpap.com sells one for less than $50. https://www.cpap.com/cpap-machine/fishe ... amber.html

Guess that confirms my concern....

Somebody had told me that my machine could handle a hose up to 10', but I wondered if the addition of the HC150 factored into the length limit. Guess I'm staying with my 6' hose.

Wonder if I want to get a pressure gauge though....

The Dreamer.

10 foot hose won't make much of a difference in CPAP mode than using 6 foot hose. Extra length does increase airflow resistance but the machine will generally compensate to maintain pressure with extra length.

It is only when using APAP mode that this could be a concern because while the extra 4 feet of hose does not drop the pressure at the mask end that much (less than 1 cm), it does affect the machine sensor and the APAP algorithm relies on the machine sensor to adjust pressure. The additional airflow resistance due to added hose length affects the transient response (how quickly and how much change occurs in airflow) which the sensor uses to determine snores and flow limitations. If the transient response is not accurate, the APAP algorithm will not respond accurately.

Well that is my understanding of 10 foot hoses and I'm sticking to that unless someone can convince me otherwise.

BTW - High ventflow masks also affect the transient response of airflow (though the issue is caused by sensitivity rather than airflow resistance) and APAP algorithms.

Dreamer......

Since your machine is not an "auto".......the only problem you might experience....is your machine having difficulty reading "snores", "hypopnea's", "Apneas", and "Flow Limitations" for your printed report.

Your machine senses little variations in pressure with pressure transducers.......and when we lengthen the column of air between you and the pressure transducers, the increased "compressability" of the air makes it difficult for the sensors on your machine to "sense". Said another way.....with a long hose, the air inside is "springy"....and that "springiness" has a tendency to "damp" (smooth out) the pressure waves that your machine reads. Your AHI will probably be artificially lower with a long hose.

Your (non-auto) machine runs at a constant pressure (assuming no leaks from your mask or your mouth), so the length of hose does not cause a pressure drop that can be measured.

Gerald

I been using my 10ft. hose for about two months now, I guess it's ok

I have been using the longer hose too for the last few months and haven't had any problems with it..

The HC-150 guide states that it may interfere with APAP response to events. I use that humidifier with an 8' hose and notice a difference when traveling without it. But since my numbers are in line I don't mess with the setup.