Heated Humidifier and total AHI

[flylow]

I always seem to think I have this cpap thing figured out but usually get proven wrong so let me ask this question.

Has anyone correlated the use of the heated humidifier with increased AHI? I accidentally used mine in passover mode and had fantastic numbers (AHI ~2). To see if it was a fluke, I have been keeping it off and even saw a 1.6 AHI and only one night at 4. Four nights does not make a correlation but it is really starting to make me think that for me, there is a significant difference between a heated setting of 1 and no heat. What a difference it does make in how I feel when I have an AHI of 3 or less!

[Sleeprider]

There are some variables you might not be taking into effect. It appears you live in the East and my understanding is, you are currently experiencing relatively high ambient humidity levels. It may well be that your humidity needs are being met without the addition of moisture from a humidifier.

We currently have an outdoor humidity level of 7%. Not only are fires burning making the air smoky where I live, but running the XPAP without humidity is a recipe for a dry, sore throat and nasal passages.

I tend to agree that excessive humidity in the pressurized air is equally bad to inadequate moisture, but I don't think you can correlate good AHI results to decreasing humidity. I think you would see that there is an optimal level somewhere between 40 and 90% relative humidity, and that problems would correlate with dryer (<40%) or condensing (100%) moisture levels.

[SleepyNoMore]

flylow,

I use my HH setting on 1 and my average (AHI) going by James Skinner's Encore Pro Analyzer is 1.7, I have seen it much lower and even higher using that setting.

I accidentally had set my HH from 1 to 2 and didn't notice that night and found that my AHI was 2.9 with a nasal pillow full of water from the rainout thing) and since i'm getting a piggy snout from using them, I almost drowned , but then my AHI another time (with the setting on 1) was 7.8 so go figure

Really, who knows! One one hand , I say yes... One the other hand, I say no but on both hands, I just throw them up and say MAYBE!!!

We need Snoredog, restedgal, wulfman, slinky, and all of the rest of the pro's for this topic!

I can't wait to hear all of their input on this one, thanks for bringing it up

[ozij]

[quote="flylow"]I always seem to think I have this cpap thing figured out but usually get proven wrong so let me ask this question.

Has anyone correlated the use of the heated humidifier with increased AHI? I accidentally used mine in passover mode and had fantastic numbers (AHI ~2). To see if it was a fluke, I have been keeping it off and even saw a 1.6 AHI and only one night at 4. Four nights does not make a correlation but it is really starting to make me think that for me, there is a significant difference between a heated setting of 1 and no heat. What a difference it does make in how I feel when I have an AHI of 3 or less!

[Captain_Midnight]

Flylow asks...Has anyone correlated the use of the heated humidifier with increased AHI?

Yup, I can confirm your observation.

I get decent AHI (<1) from either no humidification or with passive humidification. However, if I accidentally nudge the humidification dial to heat level one or higher, my AHI usually triples.

Why, you ask?

Well, sufficient moisture is necessary to keep airway membranes moist, too much and you get the same result that you get when you steam a bucket of clams. And, for some apneic patients, there is steam-induced swelling and accordingly more events.

Others here have posted similar experiences (I think that Wulfman is one). I do believe that there is a large population of PAPpers that dutifully cranks up their humidifiers, thinking that its always the right thing to do, and then they still have too many apneic events, and can't explain why.

Certainly, many folks do benefit from higher levels of humidification, each of us patients is different. However, I think that at least one of the reasons that some can't get great or even good results from PAP therapy is that some of us respond negatively to heated humidification.

One parting thought. I noticed from my data reports following an evening of heated humidification that the first hour or so were usually just fine. It takes a while for the steam to swell the tissues.

Hope this is useful.

Regards all - - Tom

[NeedinZs]

What strikes me is how differently we all respond to the little tweaks in our therapy. What works for one, has the opposite effect for others.

It's great when you find the little things that seem to make a difference for you individually. Even though it may not be the answer for everyone, this forum is great for putting suggestions "out there". It gives others something to think about and try, that we may have never even thought about on our own.

[deerslayer]

Food for thought, good ? i use 1 and have had an AHI of.05- .07 for a week since the last tweak. definitely will use passover mode tonight to see if there is any differance. BTW last night was for 8 1/2 hrs. blissful sleep

[Sleeprider]

Well, here is what I have so far. The graph below is from Encore Pro Analyzer and I noted humidity levels. The graph suggests a trend of decreasing AHI events but they are not apparently correlated to humidity. I first received my machine May 26, but only had EncoreViewer, so I lost some detail data until I got EncorePro which stores the data.

From May 26 to June 2 I had no humidifier at all. It was delivered and used for the first time on June 3 at a setting of 3. The AHI did not significantly change. On June 4 I dropped the setting to 1. That was the highest AHI of my therapy, with particularly bad obstructive events. AHI has trended downward since. Last night (June 10) i ran the humidifier in passive mode and had a very good night, but hard to say its related to humidity. I think, at least in my case, humidity is not correlated in a statistical sense to AHI; however a low level of humidification seems to be related to the best results vs too little or too much.

[Flying_Norseman]

I set mine according to how humid the weather is on a particular day. I need to have more moisture, so the higher the number the better for me. In dry times I crank the heater all the way up and at times like the last few days here in the NE, I turn it down a few notches.

[flylow]

My take away from this thread is that the level of humidity is important. The exact requirement probably varies from person to person. Swollen tissues, resulting in increased apnea indices, is likely the result of too little or too much humidity. All of this time (10 months), I have obliviously stuck with a heated humidifier setting of 1.

These units presumably control the heat by controlling the power at fixed levels dependent on the setting chosen. A better, next generation, way of controlling this would be to use a feed back loop, a relative humidity sensor and control to a specific RH value. Woo hooo..... another variable to track and tweak. Bring it on Resmed or other manufacturer. Since Respironics can't fix a simple software/firmware problem to provide uninterrupted detail data, there is little hope that they would actually latch onto this idea.

[ozij]

Sandman Auto, Covidien (Puritan Bennett)'s Sales Brochure.....

ADVANCED HUMID CONTROL (HC)
The Sandman Auto Humid Control humidification system provides
precise levels of humidification by continually measuring the voltage
and current delivered to the heater. This allows for a constant
differential between water and air temperature to minimize tubing
condensation, and gives patients a stable humidification level
throughout the night for highly effective and comfortable therapy.

Meaning that - once you've set it - the relative humidity will stay stable, no matter what the outside temprature is.

Also meaning you better not keep that machine in a drawer, where the water temp may be less exposed to changes in the room temp.

And - this is nice - when the pressure is higher, blowing more forcefully over the water surface, and possibly cooling the water temp, the heating will go up, and the humidity will remains the same.

The way I understand it - once you've figured out your comfort level, the machine will keep it stable.

At least they're trying.
O.