Tube Size - 12mm, 15mm and 22mm

[MrIvanDrago]

Does tube size affect therapy? I have read older posts and just watched a recent YouTube video where the Australian guy explained how a larger tube, i.e., 22mm, could minimize side effects such as dry mouth, eyes, leaks, etc. The reason is that smaller tubes need more air velocity, causing unwanted side effects. I have been using the ResMed heated tubing (15mm) for over a year, but I am considering trying a larger tube to see if anything changes.

Has anyone come across this with their therapy?

Here's the latest video I watched for reference:

https://youtu.be/cXW6uA9ZJcw?si=dUYjgisaXU5ML8j2

[Crimson Nape]

The hose ends on all CPAPs (except the travel models) are 22mm. One of the few standards used by all manufacturers. The hose diameters are 19mm for a standard hose and 15mm for a slim style. Since the slim style has a smaller cross-section area, it must increase the air's velocity to provide the same volume of air to the patient. This elevated velocity will increase the drying effect.

As a side note, I personally have found that the larger diameter hose is a little quieter than the smaller one. The reason for this is that the hose ribs create air turbulence in the hose. The smaller diameter hose, with its increased air velocity, increases the turbulence, thus causing a sound increase.

- Red

[MrIvanDrago]

The hose ends on all CPAPs (except the travel models) are 22mm.  One of the few standards used by all manufacturers.  The hose diameters are 19mm for a standard hose and 15mm for a slim style.  Since the slim style has a smaller cross-section area, it must increase the air's velocity to provide the same volume of air to the patient.  This elevated velocity will increase the drying effect.

As a side note, I personally have found that the larger diameter hose is a little quieter than the smaller one.  The reason for this is that the hose ribs create air turbulence in the hose.  The smaller diameter hose, with its increased air velocity, increases the turbulence, thus causing a sound increase.

- Red

Have you noticed any difference with drying out your throat or nose? Thinking about trying it tonight, as I have only used the ResMed heated hose.

[Crimson Nape]

To answer your question, no drying out. The heated hose is full size (19mm). Since switching to the 19mm full size hose, I haven't used the humidifier tank in over 2 years. I have the side plate in its place. I have a little hygrometer in my room, and reports between 35% (winter) and 55% (summer) year round.

- Red

[MrIvanDrago]

To answer your question, no drying out.  The heated hose is full size (19mm).  Since switching to the 19mm full size hose, I haven't used the humidifier tank in over 2 years.  I have the side plate in its place.  I have a little hygrometer in my room, and reports between 35% (winter) and 55% (summer) year round.

- Red

With a slim 15mm inner diameter and a length of 6.6ft, the ResMed ClimateLineAir 11 Heated Tubing is lightweight and flexible, making it easy to manage during sleep. This is the newest heated tubing from ResMed. I bought a 19mm diameter non-heated tube to try out tonight. Thanks for your input on this topic, appreciate it!

[G. Szabo]

This elevated velocity will increase the drying effect.

Sorry, but I see differently. Indeed, higher velocity dries quicker; however, only in the tube in which there is nothing to dry. Once the air reaches the mask, its velocity becomes the same (for the same mask) regardless of the tube diameter. 

The CPAP instrument controls the volume rate, which will be the same in the mask even for different tubes. The drying effect depends on the volume rate, which will be the same in the mask. 

But the larger diameter tube must be quieter, as others pointed out.

I prefer the slim tube because it is more flexible and does not alter the mask position.

[MrIvanDrago]

The Problem with Slimline Tubes
Many CPAP users are familiar with the 15mm ‘slimline’ tubes, known for their smaller size and lighter weight. While these features make them seem attractive, there's a downside. The smaller diameter of these tubes results in higher air velocity, leading to several discomforts such as nose, throat, and mouth dryness, increased turbulence, noise, mask leaks, and even stomach pains. 

Switching to a 22mm Standard Tube Can Help
The 22mm standard tube, though slightly larger and heavier, offers a remarkable improvement in comfort. The larger diameter slows the air velocity, making the airflow feel more natural and reducing the issues associated with high airflow speed. This change can particularly benefit those who experience discomfort with the slimline tubes.

[BoxcarPete]

Mr. Szabo got it correct, though I would say that the effect might be slightly noticeable with certain masks. The smaller the mask the more likely it could have an effect, maybe in a Bleep which is a tiny little thing that sticks right to your nose. With the "tube on top of head" style masks there will be no noticeable difference whatsoever, as the flow will have had enough time to find its new groove by the time it gets into the actual mask portion.

As to the claims, I think noise is the most legit followed perhaps by stomach pains. LankyLefty has found that aerophagia can be attributed in part to airstream velocity and found that Vcom can help moderate that for some people. It's not super well substantiated, but it's a possibility.

[MrIvanDrago]

So I tried the 19mm tube last night, first time I haven't used a heated tube in 2 years of therapy. Might be coincidence, but had the longest night ever with the machine, no dry mouth for the first time in as long as I can remember. I used the humidity, just not heated and a tube cover. 

And, my AHI was 0.0.