Sierra

I change my P10 nasal pillow cushion every 1.5 years whether it needs it or not.

Ideally you want a sleep technician to set your machine up. However, if you already have a machine, then as a starting point it would seem reasonable to just set your new machine the same. What are the settings on your old machine?

See the technical manual at the link below. Air filter on page 21, and the reservoir to machine seals on page 24+.

AirSense 10 Technical Manual

A new model seems to be somewhat overdue now. But, who knows??? My wife has an S9 that is getting up there in age, and I would like to get the new model too. However, at least in Canada there is now a huge difference in price between the ResMed and DreamStation. I like the ResMed better, but it is hard to justify the extra $400 per machine cost.

I also have central apnea issues and my AirSense AutoSet machine is set to CPAP fixed pressure mode, 11 cm in my case. If that is what you are doing then yes if you set the tube type or mask type improperly compared to what you are actually using then the indicated mask pressure will not be what you are actually getting at the mask. I cannot however give you any idea how much it will be off though. The error must be significant or they wouldn't give a different setting for a different type type.

The AirSense 10 does not measure pressure at the mask itself, but only estimates it. To correctly estimate the pressure at the mask the machine needs to know how much restriction there is in the tubing so it can subtract that amount from the pressure it measures right in the machine. The other issue is that there is constant bleed air flow out the mask vent. It also needs to compensate for that lost air flow. The tube setting you choose just changes the pressure drop calculation. Same when you select the mask type. However that said, if you have the machine in automatic mode it will set the pressure to whatever works. Your mask pressure indication on the machine or if you use SleepyHead or OSCAR may be somewhat in error from what it really is, but since the machine is in auto it just adjusts based on the occurrence of apnea events. It self corrects. If you are in fixed pressure CPAP mode then the error becomes more significant. The pressure you think you are getting at the mask will not be correct. And, in CPAP mode the machine cannot self correct.

That all said, you should not be getting any hissing sound on inhale. I don't see how the tube size setting would help. If you actually go to a larger tube size it would reduce the velocity in the tubing. But I use a slimline and do not hear any hissing on inhale compared to exhale. You say you have replaced the gasket. Do you mean the gasket on the water reservoir? If so, then I would also check the silicone gaskets that seal the reservoir to the machine. Also make sure you are fully inserting the reservoir into the machine. Last, have you replaced the air inlet filter recently? The machine has to supply the most air during inhale and the velocity through the filter will be highest on inhale. If it is getting plugged it might hiss???

Hope that helps some,

I am not a doctor and really can't give you any kind of medical advice. However, I do suffer from apnea and heartburn. I don't really think one causes the other, but in my case share a common cause - being overweight. It seems that does not apply to you. Before CPAP it used to be a normal occurrence for me to wake up during the night and need to take some Tums to stop the heartburn. Now I normally just take two before I go to bed and put the CPAP machine on, and never have to get up due to heartburn. So perhaps there is some association...

The best way to determine if you have sleep apnea and the type is to have a sleep test done. Some countries allow the use of home study equipment which is a lot less expensive. Normally a Stop-Bang quiz and or Epworth are given first to determine probability you may have apnea.

A CPAP machine can report the apnea score, but that is while you are being treated with at least 4 cm of pressure. It is an indication of apnea but to get an accurate score you need the actual sleep test which is done with no pressure.

I would not worry about the going under anesthetic. Your breathing, oxygen, and heart rate are monitored carefully when you are under.

Hope that helps some.

On the P10 I use the largest size cushion and it does not seem to be all that big. This mask needs to seal on the nose rather than in the nose to be comfortable. I would be afraid it may be too small for you. And yes the straps are flimsy.

My wife uses the F&P Brevida. It is a different style of nasal pillow mask that might work for you. My wife likes this mask better than the P10 which she has tried. Rather than having somewhat prong style nasal cushions it goes more over the nose and just seals in the nostrils. It would seem impossible for the nasal prongs to go too far into the nose. It only comes in two sizes and is said to fit a wider range of nose sizes. It also has a more substantial headgear than the P10 has. The straps can be adjusted for length, unlike the P10.

I see that the 1800CPAP place have them, with a claim that you can get a credit if you try it and don't like it.

"I'm just not understanding what my machine considers a clear airway event vs. flow limitation vs. obstructive vs. pressure pulse vs. a RERA event."

A clear airway event is when there is no obstruction of flow. You just don't breathe in or out. Clear airway events are essentially central apnea events. Flow limitation is when the machine senses restriction in flow but not enough to cause an obstructive apnea event or hypopnea. I am not a medical professional but here is my understanding of the types of events, in order of severity:

1. Obstructive Apnea - Caused by total blockage of the airway for at least 10 seconds
2. Central Apena (clear airway) - Caused by the body simply not attempting to breathe for at least 10 seconds
3. Hypopnea - A partial reduction in air flow for 10 seconds or more. They may be due to obstruction (more common) or central apnea.
4. RERA - Probably better explained by this link. However I believe it is similar to a hypopnea but there is no reduction in oxygen levels. Since the machine does not measure oxygen levels, I don't know how it distinguishes between a hypopnea and RERA.

Both CA and OA events are not good. CA is much harder to treat. Flow limitation I am not so sure about, but it may be a partial hypopnea that does not go to 10 seconds in duration.

It is always very difficult recommending a mask for someone else. The expectations and fit can vary widely. Your best bet is to find a place that will allow returns. CPAP.com in the US does that, but not so sure about Australia.

One possible solution is to go to a nasal mask instead of a nasal pillow. My wife used a ResMed Mirage FX mask for some time before she switched to a nasal pillow type. The only issue is that she had to keep it tight to prevent leaks, and it left marks on her face from the straps. You do still have to get one that is big enough to fully enclose your nose though. I tried her mask and it irritated me because my nose was too big for the mask size she had, and kept touching the mask. Like having an itch on your nose with no sway to scratch it.

Another possibility is the newer under the nose mask. I believe the Phillips DreamWear Under the Nose mask of this type has one insert that is more of a slot that goes across the bottom of your nose instead of into the nostrils. It may be more adaptive to different nose sizes. Don't know, as I have never tried it. Also this mask type has different insert options to try without replacing the whole mask.

What pressure are you going up to? More pressure always makes it more difficult to get a mask that seals without being too tight.

Yes, there seems to be an anti-immunity crowd growing. It seems that those that get an asymptomatic version of the virus get the least immunity, and it does not last as long. The early vaccine testing seems to be showing immunity levels 2-3 times higher than achieved by actually getting COVID. The Moderna vaccine seems to have suffered a setback in the testing. They are new to making vaccines and can't get their act together with a testing protocol. Perhaps the Oxford vaccine trials will go better.