Tube temp

I was desperate for solutions, i had horrible dry throat, cough and congestion. I talked to 3 different doctors and 2 different respiratory therapists, even got scoped. My uvula was enlarged due to inflammation/ dryness / irritation and i had the worst sore throat. I tried humidity levels 1 trough 8 for 2 months and there was not much of any change besides the throat a little better. First 2 weeks no issues. and he said this about tube temp, i have the resmed 10 with p10 nasal pillows. I watched 2 videos about uncle niko about humidity and he said based on his chart: (to avoid rainout)

The First number after the humidity levels represents heated tube temp min. While the second number represents absolute humidity heated tube

Humidity Level 1. 61 / 14
Humidity Level 2. 70 / 19
Humidity Level 3. 75 / 22
Humidity Level 4. 81 / 24
Humidity Level 5. 86 / 27
Humidity Level 6. 86 / 30
Humidity Level 7. 86 / 32
Humidity Level 8. 86. / 34


Now the respiratory therapist when I got the cpap, told me to keep my heated tube temp 2 degree abuse my ac controlled environment at 72, so the tube temp was set at 74. So for 1.5 months, I tried every humidity setting with no real success and the only thing that's been helping me is putting the tube temp to the max with humidity setting 5 and now zyrtec and a nasal saline mist. I have very minimal mask issues, very low, and average ahi is now 0.4

Why did this work? Relating to tube temp? If I up the humidity higher, will I get more humidity or just condensation/ rainout and the amount of actual humidity won't increase since the tube can't carry it?

dustinwillis1983 wrote: ↑

Sat Nov 02, 2024 9:35 am

Now the respiratory therapist when I got the cpap, told me to keep my heated tube temp 2 degree abuse my ac controlled environment at 72, so the tube temp was set at 74. So for 1.5 months, I tried every humidity setting with no real success and the only thing that's been helping me is putting the tube temp to the max with humidity setting 5 and now zyrtec and a nasal saline mist. I have very minimal mask issues, very low, and average ahi is now 0.4

Why did this work?

It worked because your nose didn't read all the memos from the respiratory therapists and doctors saying that using a hose temp barely above your room temp ought to fix your problem.

Your nose apparently wants the air in the hose to be very, very warm with relatively high relative humidity. Setting the hose temp to its max of 86F allows a humidifier setting of 5 to add more absolute humidity to the air in the tube: Warmer air holds more water vapor.

Relating to tube temp? If I up the humidity higher, will I get more humidity or just condensation/ rainout and the amount of actual humidity won't increase since the tube can't carry it?

Look at those numbers you cited:

The First number after the humidity levels represents heated tube temp min. While the second number represents absolute humidity heated tube

Humidity Level 1. 61 / 14
Humidity Level 2. 70 / 19
Humidity Level 3. 75 / 22
Humidity Level 4. 81 / 24
Humidity Level 5. 86 / 27
Humidity Level 6. 86 / 30
Humidity Level 7. 86 / 32
Humidity Level 8. 86. / 34

If you keep the hose temp at 86F and increase the humidifier setting from 5 to 6, 7, or 8, the absolute humidity in the air inside the tube will increase. And that means the relative humidity in the hose will also increase. Relative humidity is the ratio of how much water vapor is in the air at a given temperature divided by the maximum amount of water vapor the air can hold at that temperature.

Now, it's a whole 'nother set of questions of whether increasing the humidifier setting from 5 to 6, 7, or 8 will make your nose feel any better and whether a higher humidity setting will trigger enough rainout to bother you.

Rainout in the hose happens when the relative humidity in the air in the tube reaches 100%. In other words, when the air in the hose is holding as much absolute humidity as it can hold at that particular temperature. At 86F, air can hold just over 30 grams of water per every cubic meter of air. Now if those second numbers are the grams of water per cubic meter of air in the tube at that humidity setting, then rainout could start to happen with a humidity level set to 6, and is more likely to happen if the humidity level is set to 7 or 8. However, some people (including Pugsy and myself) do have luck running our humidifiers at settings that ought to be triggering rainout issues. In some sense, our noses seem to be less bothered by rainout than most people's noses.

In my case, I use a humidifier setting of 8 with an unheated hose in a bedroom where the ambient air temperature is usually at or below 62F. You would expect that my nose would be drowning in rainout. But I run my hose under the covers and next to my body, and for the most part this minimizes the problem with rainout. If my hose gets a small sag in it between the machine and where it enters under my bed blankets, I will wake up (sometimes) to the sound of gurgling in time to my breathing. It's caused by a small amount of water that had condensed and settled in that lowest part of the hose. All I have to do is lift that part of the hose up so the water runs back to the machine, and my problem with rainout is fixed.

Finally I'll add: You can find a relative/absolute humidity calculator at https://www.omnicalculator.com/physics/ ... e-humidity. If you set the absolute humidity units to grams/cubic meters, the 100% relative humidity numbers at the various temperatures are quite close to the second number in your table. In other words, Resmed expects people to have rain out problems if the hose temp is 61F and the humidity level is set to anything higher than 1.