Hose Restricting Airflow?
I have been using a Philips Dreamstation 2 Auto for about a year, since receiving it as a replacement for the cancery old one.
Just a couple weeks ago received the 12mm microtube HT12. Have been using that. Recently I have been experiencing what feels like suffocation, usually happens around 4am, so around 6 hours after I go to sleep. It was hard to tell if it was a CPAP issue or just imagining it.
Well last night I remembered that this issue has only occurred since using the new hose, so I swapped to an old much higher diameter hose, and the issue is 100% gone. Switching the hoses back and forth it's totally obvious that the HT12 was restricting airflow and I was in fact slowly suffocating.
I'm not sure what's causing the issue with the hose. The machine automatically detects the 12mm hose and adjusts for that. The hose is fairly long, and I have my CPAP on the ground near the bed, but it does result in a loose twist of the hose. Could that be causing issues? If so, where do people have their CPAP while in operation? The hose is so long I wouldn't possibly be able to reach the machine from bed if it was far enough away to prevent any looping.
Thanks for any help.
01-26-2023, 04:31 PM
(This post was last modified: 01-26-2023, 04:33 PM by mesenteria.)
RE: Hose Restricting Airflow?
We would need to see some data, and probably concurrent video, so that we can pinpoint what's going on.
It may not be useful to you, but I keep my machine in an open night-table drawer. The entire tube rests across my body between the top sheet and the first cover. The cover helps to keep the hose draped over me while I sleep, including during turning, and it also serves as an insulating 'sleeve' to prevent any rainout that might take place due to the cool nighttime air my wife and I prefer.
It is possible that your hose is getting severely constricted, but not terribly likely. The coiled heater wire should prevent all but severe torsion and stricture. Instead, if the hose size matters, and when does it not (cough), you should probably do what seems to be indicated. If it is a reliable result, and desired, when you change back to the larger hose, and this happens on every night and every trial, then that must be the cure you need.
One other possibility: do you by any chance have occasional congestion in your nose? Many people's inner passage swells on one side, or on both, for a spell during the night. I have it happen most frequently within an hour of the time I'm likely to awaken, but it can happen even at the other end of the sleep period. You may need a decongestant.
RE: Hose Restricting Airflow?
(01-26-2023, 04:31 PM)mesenteria Wrote: We would need to see some data, and probably concurrent video, so that we can pinpoint what's going on.
I'll see if I can get some good data to post via OSCAR.
Rainout isn't happening, I do frequently have significant nasal congestion. I have a variety of ways to help with that, but it's unrelated here.
I tested by connected the 22mm diameter hose and setting CPAP to 10 cmh20 pressure. The flow is significant and continuous. Breathing through the mask in this case I felt continuous pressure.
Then immediately swapped to the 12mm hose, ensured the machine changed settings for the 12mm hose, then try the same mask at 10 cmh20 pressure. While breathing in I can tell the mask becomes an underpressure zone as the mask bends inward, but it doesn't do that at all with the 22mm hose. It feels physically difficult to breathe, even with the 10 cmh20 pressure whereas I usually use 8-9 while sleeping. Then I tried stretching the hose out so it's completely straight and the flow rate/pressure does seem to increase slightly, but still lower than the 22mm hose.
RE: Hose Restricting Airflow?
You could have someone switch the hoses and not tell you which one it is. Just put everything on in the dark or with your eyes closed.
But essentially, if the hose fits, it is safe to use. There's the smaller Resmed slimline and the wider heated. Both work the same.
Which reminds me...is there a setting for the machine for you to tell it which hose you are using?
PaulaO
Take a deep breath and count to zen.
RE: Hose Restricting Airflow?
A narrower tube has less volume and delivers the same airflow at a higher velocity and turbulence to the mask. This is true anytime a tube or pipe diameter is reduced. It is likely that the tube is still delivering the same volume, but it is certainly possible the difference in the flow characteristics is perceptible by you, the user. An alternative to the smaller, lighter tube might be to use your larger tube with something to suspend the weight from the headboard or a tube support rather than having it lay across the bed.
