HOSE LENGTH?

[DoriC]

If I use an 8ft length hose, does it affect pressure in any way? When Mike naps on his recliner the hose just about reaches and I'm afraid he might pull it off the table one of these days. He uses a Standard lightweight 6ft hose now. Thanks.

[Pugsy]

No, using the 8 foot hose won't reduce the effectiveness of the pressure.
From what I have read even the 10 foot hoses don't really lessen the pressure effectiveness all that much.

[tattooyu]

That's good to know. I was wondering that myself.

[jnk]

The additional length does not cause a significant decrease in patient airway pressure.

https://www.cpap.com/productpage/10-foo ... -ends.html

[SeekSleep]

Hope it isn't thread hijacking to tag on the the OPs question, but would it affect things in a negative way if you used a two foot regular sized extension in conjunction with a 6 foot slimline hose, leaving the S9 ASV machine set to the slimline setting? I too find the hose just a little short when put in the location that works best for me.

[jdm2857]

Standard Air Tubing

14987 Replacement Standard Tubing (6'6")
14986 Autoclave - Dark Grey (6'6")
14994 Standard - Light Grey, Ribbed (6')
14999 Standard - Clear Grey, Ribbed (9') (S7 Series, S8™ Series, S9 VPAPs Only)

I didn't think that hose length mattered that much either, but then I remembered
that my S8 has a setting for hose length. So I took a look at their site and found
the above. Note that the 9' Standard Tube is specifically not mentioned for
S9 machines except for the VPAPs.

[DoriC]

So I'd be good to go with the 9'? I use the Vpap Auto. Thanks for checking that for me.

[ironhands]

technically, I think there is a drop in pressure when any length of hose/pipe is increase, however, it's probably so small it's not an issue. If there is somewhat more resistance to the airflow, wouldn't it just work a little harder to maintain the desired pressure anyway?

Specifically with an auto machine, I'm certain it would adjust itself anyway. If it saw the pressure was lower than optimal for whatever reason, wouldn't it correct itself?

I don't know from experience, but my inner engineer would have designed it that way.

I'd think it would be best to just call up your DME and tell them you want a longer hose, and want to know if you need to adjust the pressure for it. They'd know best.

[SleepWellCPAP]

Hello DoriC,

Decided to use a manometer to verify pressures using a ResMed VPAP Auto with the machine set at 12 cmH2O. Here's what I found.

At tube lengths of 6, 8, 10, 12, 18, and 22 feet, the manometer read exactly 12 cmH2O. I didn't think it would do that, but it did.

Then I put a mask on and checked pressure while breathing. At 6 feet, there was very little preceptible flex. Basically the needle stayed right on 6. Then I tried 10 feet and found a 1 cmH2O variation in pressure both above and below the 12 cmH2O mark. Then I went out to 22 feet, and the flex above and below was between 2 and 3 cmH2O. At 22' it was like I was having to draw air through the tube. At 6' it was much easier to breath and at 10' it was a little harder but not much.

Does that help? If not let me know, have a great day!

Jim

[chunkyfrog]

If you are using exhale relief, or are using auto,
I suspect the length could add significant time to machine responses.
Somebody want to test that?

[SleepWellCPAP]

Good point chunkyfrog,

As far as EPR or C-Flex, hose length would definitely magnify how much and how long the pressure dropped. When I did my test I turned EPR to off and at 22 feet, logically, if EPR were set to three, I would have had a lot of difficulty breathing.

Back to the manometer. Same machine set to 12 cmH2O with EPR=3

At 6', the machine ramped from 9 to 12 smoothly and with my breathing. At 8 foot, things were pretty much the same. At 10 feet I noticed the pressure lagged behind and didn't get to 12 until the end of my inhalation. I also noticed a definite pressure spike. At 12 feet in length, the pressure never quite got to 12 and the spike was significant. At 18 feet in length, the pressure barely moved off the 9 cmH2O mark.

Doing just this little bit of research, it appears one would have to be careful adding EPR to a circuit longer than 8 feet. Maybe have the patient try it and see how they feel as I'm sure breath rate and tidal volume would enter into the equation as well. At 12 feet and beyond, you may as well just reduce therapy pressure as EPR ends up creating disruptive spikes in pressure.

[jnk]

. . . (9') (. . . S9 VPAPs Only)

. . .

. . . EPR . . . At 10 feet I noticed the pressure lagged behind and didn't get to 12 until the end of my inhalation. . . .

Related points, maybe?

Perhaps true bilevel does better with longer hose lengths than EPR does?

Interesting.

[SleepWellCPAP]

Thinking this through a little more on my way home tonight, I wondered, since this question boils down to the volume of the extra tube length. What if, rather than standard 1 inch bore, a slimline is used?

Estimating a 30% reduction there, you should be able to go to 12 feet, i.e., two slimlines joined together without any problem. Course I'll have to test that with the manometer and will report the results, but that should be enough distance for most. At least I think.

By the way, if anyone needs pressure information beyond 22 feet, just let me know. I'll probably have to throw my garden hose on the truck.

[DoriC]

Guess what fellas, I'm glad you're having fun but it's making me nervous! I just did a little table rearranging and the hose has a little more play in it now, but I'm glad it turned out to be an interesting question !

[SleepWellCPAP]