Question about Rain Out

Shari · Post by **Shari** » Fri Jun 22, 2007 9:26 am

I have been seeing lots of posts from people trying to solve rain out problems. The posts state that the humidifier is set very low (1 or 2) and they are still getting rain out.

My question; does pressure have an effect on rain out?

I ask because I have used a ResMed S8 Escape and a ResMed VPAP III with appropriate heated humidifiers set on the maximum setting (if I set it any lower, it is too dry) and have never experienced any water or condensation in my hose or mask.

My pressure on CPAP was 18, on BiPAP it is 21/18. My room temperature is between 65 and 68 winter and 70 and 75 summer. Machine is positioned 8" off the floor. Mask has usually been a Comfort Gel or Swift, with the hose coming straight down. Recently I have tried a Breeze and a ComfortLite 1 and 2 with the hose going up over my head. I do not use a hose cover.

The only time I have ever experienced condensation was my first titration before they increased the pressure much.

Those that experience rain out? What is your pressure setting?
Thanks
Shari 2

DP · Post by DP » Fri Jun 22, 2007 9:35 am

Rain out is usually a result of the outside room temp being much cooler than the air that is traveling through the hose. Insulating the tubing will usually solve the problem.

Linda3032 · Post by **Linda3032** » Fri Jun 22, 2007 9:38 am

Shari, I've thought for a long time that pressure has an impact on rainout.

I'm one of the few Aura lovers that get rainout in spite of all the preventative measures I've taken. And my pressure is only 7. Granted, with all my precautions, I now only get a few droplets which I can live with.

Shari · Post by **Shari** » Fri Jun 22, 2007 9:56 am

DP wrote:Rain out is usually a result of the outside room temp being much cooler than the air that is traveling through the hose. Insulating the tubing will usually solve the problem.

I am aware of what rain out is, and how most people are able to solve the problem.

I guess another way to ask the question is why don't I get any rain out? My humidifier is set to maximum, I do not insulate my tube, and my room temperature is fairly cool.

Linda you are one of the posters that really got me to wondering about this.

Linda3032 · Post by **Linda3032** » Fri Jun 22, 2007 10:46 am

Shari, I also think it has alot to do with the different masks. I never had rainout with my NasalAire with the hose down under the covers. But once I went over the head with my Aura, I got it.

topher · Post by **topher** » Fri Jun 22, 2007 10:52 am

I have never had rainout, only ben on cpap 4 months 17cm, maybe higher cm less chance, who knows?

ozij · Post by **ozij** » Fri Jun 22, 2007 2:56 pm

Pressure and type of mask.

Suppose it's a hot and humid day, and you have a fun running, but you're still sweating. You turn the fan on higher, and even thought it's blowing humid air at you, your sweat dries.

I'm in same camp as Linda - love the Aura, have an average pressure of 6.6 per night, and take many precautions against rainout.

O.

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CPAPopedia Keywords Contained In This Post (Click For Definition): rainout, Aura

tillymarigold · Post by **tillymarigold** » Fri Jun 22, 2007 4:37 pm

Just to agree with everyone else, higher pressure = less rainout.

My guess as to why was different as to ozij's but maybe I misunderstand how CPAP works. I was thinking higher pressure = moving faster through the tube = less chance to condense.

I use a hose cover and keep my humidifier set between 1-2. My average pressure is 6.2 and 90% is 7.0. With my ComfortLite 2 I got really bad rainout. With my Hybrid I've only gotten it once (and that was when we left the swamp cooler on all night and I forgot to turn the humidifier down to compensate).

GeneS · Post by **GeneS** » Fri Jun 22, 2007 8:59 pm

I agree that lower pressure would mean lower velocity and more temperature drop in the air in the tubing which would increase the chance for condensation and rainout. If I could not stop the condensation I would either reduce the amount of moisture in the air by turning down the humidifier or keep the tubing warmer above the saturation temperature so that condensation did not happen. If the tubing goes uphill all the way to your mask the condensation will drain back to the humidifier and not to your mask and nose.

GeneS

Linda3032 · Post by **Linda3032** » Fri Jun 22, 2007 9:23 pm

[quote="GeneS"]I agree that lower pressure would mean lower velocity and more temperature drop in the air in the tubing which would increase the chance for condensation and rainout. If I could not stop the condensation I would either reduce the amount of moisture in the air by turning down the humidifier or keep the tubing warmer above the saturation temperature so that condensation did not happen. If the tubing goes uphill all the way to your mask the condensation will drain back to the humidifier and not to your mask and nose.

GeneS

ozij · Post by **ozij** » Fri Jun 22, 2007 9:51 pm

In addition to everything Linda does, I use tubular guaze to isulate the Aura itself.

1.I slip two layers of it on the Aura'a narrow hose (also do that for the Breeze) the tubes can be streched enough to slip them over the connector and onto the hose - I slip the layers on one after the other. Mine is not a decapitated Aura, which is why part of the hose - where the hose slips into the headgear stays bare...

2. In winter I also wrap tubular gauze round and round the nasal seal - one piece for the right side, one piece for the left. I roll my way up the seal from bottom to top.

Those two make a major difference for me - maybe that's why I only need two covers on the Aussie heated hose.... I started using the bandages when my hose had only its original cover - that wasn't enough -

O.

Linda3032 · Post by **Linda3032** » Fri Jun 22, 2007 9:55 pm

[quote="ozij"]In addition to everything Linda does, I use tubular guaze to isulate the Aura itself.

1.I slip two layers of it on the Aura'a narrow hose (also do that for the Breeze) the tubes can be streched enough to slip them over the connector and onto the hose - I slip the layers on one after the other. Mine is not a decapitated Aura, which is why part of the hose - where the hose slips into the headgear stays bare...

2. In winter I also wrap tubular gauze round and round the nasal seal - one piece for the right side, one piece for the left. I roll my way up the seal from bottom to top.

Those two make a major difference for me - maybe that's why I only need two covers on the Aussie heated hose.... I started using the bandages when my hose had only its original cover - that wasn't enough -

O.

ozij · Post by **ozij** » Fri Jun 22, 2007 10:43 pm

I did search for Blarg's pillow covers - much more intersing than my plain white gauze - and found a link to a picture of a deconstructed one:

viewtopic.php?p=169292#169292

O.

thisgeek · Post by **thisgeek** » Tue Jun 26, 2007 12:36 am

I had a Fisher & Paykel HC608 w/ integrated heated hose, and never had major issues with rainout.

I've now moved to an M-Series Auto w/ heated humidifier with no heated hose, and I must say I'm having huge rainout issues. If I have the humidifier set on anything above 2 my hose literally fills with water. It's a real bugger for me, as I tend to get an extremely dry throat otherwise.

It doesn't help that it's winter now, and the bedroom temperature is extremely cold. Unfortunately, South African houses don't usually cater for air conditioning, so keeping the room warm is not really an option for me.

My current pressure range is 12-20 (still trying to work out a good range for me).

I guess I'll have to coerce my wife into making some hose covers for me

rested gal · Post by **rested gal** » Tue Jun 26, 2007 1:13 am

thisgeek wrote:I guess I'll have to coerce my wife into making some hose covers for me

Good idea. And while you're at it, ask her to loan you the money to buy a heated cpap hose that you can use with any machine.

I've been using one from here for over three years:
http://www.sleepzone.com.au

When I bought a second one from them (for a backup that I've not had to use yet) I asked them to send me one without the adapter they now include with them. I wanted to keep using the Radio Shack adapter that I already knew worked well with it.

LINKS to discussions about the Aussie heated hose - to prevent rainout
viewtopic.php?t=5305