CPAPtalk.com

Warning!!! Another stupid newbie question.

I have a standard 6' hose, but I think that just another couple of feet of hose length would make things more manageable for me. I see longer ones advertised here.

Would using a longer hose affect anything?

I have a Series M Auto BiPap. The Sleep Center has me on "Auto" which usually gives me a 90% between 9 or 10 and about 6. I have been using the OPTILIFE nasal pillows most of the time.

Thanks in advance, and also, I gotta say that you folks here are WONDERFUL! I'd be lost without this forum.

Jerry.

The longer the hose the greater the pressure loss end to end.

10' hoses are generally considered to be the limit.

Last year I ran several tests where I measured pressure loss over a 6', 10' & 12' (2 x 6') hoses at different pressures.

The drop is about 1 CMS per 6' at 10 CMS pressure (while in use (breathing)).

When the air is not moving in the air tube the pressure is the same at each end of the tube (it equalizes), but when someone breathes through the tube and at say 10 CMS, there will be a loss of approx 1 CMS per 6' - that is, the machine will be showing 10 CMS but a gauge at the mask will be showing 9 CMS.

In general terms, most modern machines appear to make allowances for this.

DSM

Jerry,
From what I've read 10-foot hoses are normal for use, and work with most masks. Our host has them for a reasonable price.

Though some masks do require special tubing... usually only the one supplied with the mask.... like the Comfort Curve mask. It has one normal PAP end and the other end is proprietary to the mask.

Nodzy

seems like a very legit ? to me. have been pondering the notion of running the hose over head and using a bungee to loop. 6' don't get it

I've heard that it is not the size that matters but how you use it

...but you may not want to take that kind of chance

In addition to line losses covered in these posts you could have other losses you may want to compensate for sometime. The Respronics Bipap Auto with Biflex Manual says it automatically adds pressure based on the loss thru a 6' hose but says that additional losses will occur if other devices are added to the circuit. Based on this I assume they are not compensated for by the machine. It has a graph showing additional pressure loss if you use a bacteria filter and Respironics Humidifier. It looks like if you use either or both of these devices at 45 LPM you need to add another cm of pressure or so to your setting to compensate for the additional loss. The graph estimates the pressure loss at other flow rates. We need to ask DSM to make a graph of hose losses or get the data based on his experiment. It would be handy to have. I do not know how the M series works and do not have the manual to know what pressure losses are compensated for. If the machine measured pressure at the mask we would not have to compensate for these losses.
GeneS

I recently bought a 3 m hose and changed the setting on my resmed however after 4 days I had to go back to the smaller hose. I dont know what happened except to say they were 4 horrific nights waking up with crushing headaches. Everything back to normal now though

A cloth hose cover like the SnuggleHose makes the hose length a non-issue, however you should make sure your machine can accomodate the hose's length without comprimising your treatment.

* * *

Settings: CPAP 10cm, Ramp 10 @ 4cm, heated humidity, AHI=35

1. Main unit: ResMed S8 Elite, ResMed Humidaire 3i
2. Backup: ResMed S6 Lightweight
3. Mask: ResMed Swift II
4. Backup: NasalAire II
5. Health Tools: ResMed ResScan Data Card, CMS-50E Pulse Oximeter, OneTouch Ultra glucometer, Citrus II spray mask cleaner
6. Software: ResMed ResScan 3.3, OneTouch

If you are using an auto - any pressure loss really should not matter.

Actually, hose length has smaller effect on pressure when using CPAP mode.

In AUTO mode, there is a feed back required for the algorithm to work correctly. The longer hose will affect the transient response to the machine's sensor which may cause it to jack up pressure too high or not high enough and screw up treatment..

Where is this pressure sensor located?

GumbyCT wrote:Where is this pressure sensor located?

Inside the machine somewhere ... I have never taken mine apart but DSM and snoredog have and they have posted pictures here on the forum.

If its inside the machine - how could a hose affect the way it senses?

10 feet or under are no problem, the remstars handle that according the the manufacture. The auto machines rely of pressure feedback to detect breathing changes and levels, a hose longer that 10 feet, tends to mask the return signel, that why the manufactures design limit is set at 10 feet. Jim

OIC