CPAP: By the Numbers

[ThomasMcKean]

Last night I tried the CG FF mask for the first time. It was like I was an astronaut going up into space when they show yew how the skin on the face peels back from the gravity? Heh. That was me.

I did manage to keep it on and sleep for three hours, though. Numbers were most impressive during that time. Check this out:

Leak: 0.00L/s (????)
AHI: 5.5
AI: 0
HI: 5.5

I will have to figure what to do about the HI, but if I can get used to this monster of a mask, it may work? One thing I noticed was as a I was falling asleep, I could feel myself stop breathing. I would exhale and then that was it. There wasn't any obstruction, I just didn't think to inhale.

Very interesting. But because I noticed it, it also kept me awake for most of the night.

[Hawthorne]

I checked back through your other thread and did not find any mention of what machine
you have. It may have been there but I missed it.

Seeing these numbers, I suspect that you have a Resmed. Resmeds always report HI higher than other machines.

If it is a Resmed, your numbers for last night were excellent. The HI figure, for a Resmed, is quite good I think. Hopefully, you can get used to wearing this mask and overcome that breathing issue.

[alnhwrd]

Well, Congrats on three successful hours then! Try for three and a half tonight!

I'm sorry, but I don't know what kind of machine you have or what your pressure is. I'm guessing you have a Resmed of some kind. If that is the case, you need to go into the clinician's menu and select the "Standard" mask setting to get the machine's best guess for the leak rate for your mask. Resmeds can come in a bit high on the HI index, so 5.5 AHI with 0.0 AI is pretty good, as Hawthorne has already stated. I'm not a doc but what you are describing sounds like you may be having some centrals as you go to sleep, which is not uncommon and should stop as you become acclimated to CPAP. Unless you had a bunch of centrals on your PSG you probably don't need to worry about it. If it was continuing as you slept, it would have shown up in your data as AI's.

Keep it up, you are doing well!

[ThomasMcKean]

Yes it is a resmed. An Elite II to be exactly.

I had heard rumors of the resmeds overdoing the data. Are y'all saying this applies only to the HI and not the AI? I thought it was both? *Blink* By the way and since someone asked, pressure is 12.

[Velbor]

The issue of differences in reporting between machines is not simply one of "sensitivity." Rather, there is no universally accepted definition of an "apnea" or a "hypopnea", and each manufacturer codes their own criteria into their machines. I had posted this chart in August 2008, but the link is broken and I can't fix it, so here it is again:



If anyone has access to definitions used by other manufacturers, that would be be a helpful addition.

Velbor

[ThomasMcKean]

Last night I had the mask on for three hours and I had 0.06 AI and 22.1 HI. And the best part was I had 0.00 leaks! Today I see sleep doctor and I am hoping to get something to help me get to sleep.

[rested gal]

The issue of differences in reporting between machines is not simply one of "sensitivity." Rather, there is no universally accepted definition of an "apnea" or a "hypopnea", and each manufacturer codes their own criteria into their machines.

Exactly. Thanks for posting the picture of that chart, Velbor.

[SharkBait]

Yes it is a resmed. An Elite II to be exactly.

I had heard rumors of the resmeds overdoing the data. Are y'all saying this applies only to the HI and not the AI? I thought it was both? *Blink* By the way and since someone asked, pressure is 12.

Awesome numbers last night!!!

Any reason why you don't fill out your equipment list in your profile? Helps others help you...

[ozij]

Event Descriptions by Puritan Bennet, from the 420E manual:

When is apnea said to have occurred?
An apnea event occurs when there is no airflow for a time equal to at least 10 seconds plus 5/8 of an average breath period.
When is central apnea said to have occurred?
A central apnea event occurs when cardiac oscillations can be detected during an apnea event. The cardiac oscillations indicate an open airway, which is not an obstructed situation.
When is hypopnea said to have occurred? A hypopnea event occurs when there is a period of at least 10 seconds where hypopneic breathing occurs. Hypopneic breathing is considered to be a reduction in breathing peak airflow by at least 40% when compared to the average of the preceding eight breaths, but not enough reduction to be considered an apnea. A hypopnea event is terminated when the patient delivers 2 consecutive non-hypopneic breaths.
When is snoring said to have occurred?
A snoring event is declared by the microcontroller when there has been an acoustical vibration for at least 7% of the average breath period time of the three preceding breath cycles and if the time between snoring doesn't exceed 120% of the average breath period.
When is flow limitation said to have occurred?
Flow limitation events are determined from breath wave shapes. Flow limited breaths occur when the es (thus reducing airflow) during the middle stage of inhalation. When is Interface leak said to have occurred?

[Velbor]

Thank you, Ozij!!