Position of Blower & Humidifier

[ranman]

I'm looking to hear from anybody with experience regarding positioning of the blower unit and humidifier in relation to the height of the top of the mattress.

My current setup includes the blower running to a standalone F&P H150 humidifier. The blower has an 18" hose that connects it to the humidifier tank and a standard 6' hose that connects to the mask. Everything sits together at one level on the night stand. The top of the humidifier where the 6' hose is connected is about 4 inches lower than the top of the mattress. I also have the 6' hose routed up through the headboard and down to my sleeping position. I find that this works best to allow for movement and preventing leaks with my mask.

I think I read somewhere that the blower unit should not be positioned lower than the humidifier. This setup though has the blower situated lower because of the use of the 18" connecting hose which has to exit the blower and run to the top of the water chamber in the humidifier. The humidifier is attached to a flat tray and the heating plate attaches to this tray. This would result in the blower having to be raised up about 7 inches in order to have the blower unit positioned higher than the humidifier. This would result in the blower being higher than my sleeping position.

Because the night stand has a flat top there is no choice but to have both units side by side. The only way around not having this problem would be to use a stand with a staggered two level top so that the blower could be placed on the higher position and the humidifier slightly lower.

Because we have matching nightstands my wife would not be a happy camper if I suggested changing to a type of stand that I just mentioned!!

When I read this information regarding positioning of the two units I wasn't sure if the concern was the chance of water entering the blower from the humidifier or some issue with the blower delivering the proper pressure with it located lower than the humidifier.

I currently use both the RemStar Tank style Auto and the M-Series Auto. I have the pressure set at 12-16. I monitor my sleep data weekly. I have been using this standalone F&P humidifier since February of 2010. I have all of my sleep data saved and have been able to look through all of it. When I go on vacation I use the integrated humidifiers but keep all other settings the same as when I am at home. In all cases my weekly AHI has averaged between 0.3 and 1.2.

The reason that I started to investigate this whole thing is that I found when I use the standalone humidifier vs the integrated humidifier I spend more time at the higher pressures of 15-16. When I use the integrated humidifier with the same machine settings I spend way more time at the lower pressures of 12-13. Of course if I'm spending more time at the higher pressures I am also experiencing a higher leak rate with my UMFFM. It just got me to wondering why this is so. My next step may be to bump up my pressure by .5 or 1 when using the standalone humidifier and see how my numbers compare.

So my questions are!!

Does it matter if the blower is higher than the sleeping surface?
Does it matter if the blower is not lower that the humidifier?

ranman

[nanwilson]

Mine is level with the mattress....BUT...I route the hose up over my headboard, have never had rainout in a year and a half.

[GumbyCT]

The reason that I started to investigate this whole thing is that I found when I use the standalone humidifier vs the integrated humidifier I spend more time at the higher pressures of 15-16. When I use the integrated humidifier with the same machine settings I spend way more time at the lower pressures of 12-13. Of course if I'm spending more time at the higher pressures I am also experiencing a higher leak rate with my UMFFM. It just got me to wondering why this is so. My next step may be to bump up my pressure by .5 or 1 when using the standalone humidifier and see how my numbers compare.

So my questions are!!

Does it matter if the blower is higher than the sleeping surface?
Does it matter if the blower is not lower that the humidifier?

Because of gravity, the ideal placement would be to have the humidifier lower than your head (when laying down) and the blower a bit higher than the humidifier. Can you place a book under the blower to raise it a little? If not having both at the same level shouldn't be too bad. Just don't knock either off the nite stand.

As for the diff in pressure.
You didn't say which mask you are using or if it also has an 18" hose? The hose will add more volume and affect the way your machine responds to events, esp. when used in auto.

I have mine setup using both (on the floor) the internal and external humidifiers to use in passive mode but will not use a hose longer than 6ft bc I notice I have fewer events but feel worse. IF you must use a longer hose try just using straight cpap and maybe 1-2cm more pressure to allow for the pressure drop at your end of the hose.

HTH

[ranman]

As for the diff in pressure.
You didn't say which mask you are using or if it also has an 18" hose? The hose will add more volume and affect the way your machine responds to events, esp. when used in auto.

I'm using the Resmed UMFM. Just using the standard 6' hose as well as the 18" hose from the blower to the humidifier.

ranman

[rested gal]

ranman, I use the separate F&P HC 150 heated humidifier with any autopap I use. Both the machine and the humidifier are side-by-side on my nightstand. The top of my nightstand is higher than my mattress. I route the main air hose up overhead. I use a six foot air hose, and there's an 18 inch connector hose from my nasal pillows mask to the main airhose.

So... sounds like my setup is arranged the same as yours except that your machine and humidifier is sitting lower than your head, while my machine and humidifier are sitting higher than my head.

I have an old REMstar Auto with C-Flex stored away, and the integrated humidifier for it. I'll dig that out and use it both ways (with its integrated humidifier, and then with the separate F&P humidifier) to see if I get the same kind of pressure differences you've been seeing, depending on which humidifier is used.

As for the recommendations the manufacturers make for keeping the humidifier lower than the person lying in bed... my guess is that is to minimize the chance of rain out dripping toward the person. And maybe to be sure the person doesn't accidentally pull the machine/humidifier off a nightstand or headboard shelf... down onto their head.

[ranman]

Rested Gal thanks for the reply.

I thought that possibly having the blower unit sitting with the F&P humidifier at the same level could be the problem. The integrated humidifier for the tank style Auto connects with the 6' hose outlet just below the height of the blower outlet from the machine. That means that the blower is actually blowing out and down to the attached hose outlet. When using the F&P humidifier the blower outlet and attached 18" hose must be routed up and over to attach to the water chamber of the F&P humidifier. There is also somewhat of a loop of hose that must be routed so it is even higher then the inlet on the water chamber.

I'm wondering then if the pressure being delivered can vary because of this upward facing connection to the humidifier? The M-Series connection also has this same issue. I have 3 Tank style RemStar Auto machines and 2 M-Series ones that I cycle through and they all exhibit this same behavior. When I am using the integrated humidifiers I spend far more time at the lower range of my settings of 12-13 cm with it probably averaging about 70% of the total hours for the weekly report. When I use the standalone humidifier with the exact same settings on the blower I see only about 30% of the total weekly hours at the 12-13 cm with about 70% at the 15-16 cm. In both cases the time spent at 14-15 cm is minimal and is about 10 to 20% of the total hours reported for the week. My settings on all five of the autos is minimum 12cm max 16cm.

I reasoned that although my minimum is set at 12 for all machines the stand alone setup is not really allowing the machine to deliver a true 12cm hence the machine increases the pressure to the higher end of the pressure range more readily.

ranman

[greg-g]

Thinking logically, but with no experience as my humidifier is attached to the blower.
The only reason against having the blower below the level of the humidifier is due to the very slight risk of water flowing down the hose to the blower.
Air in the hose isn't measurably effected by gravity as its virtually weightless and surrounded by air of almost the same weight. As far as air pressures are concerned the placement of your equipment will have no effect on the delivered air pressure.
The only issue that will effect pressure is the dynamic friction loss of pressure as air flows down the hose. I don't know the magnitude of these losses, but the longer the hose and the greater the number bends, the greater the pressure loss.
An automatic machine should compensate for any losses.