New User Questions

Alright, I have just completed 6 nights with a CPAP this morning. I have to say that I feel better than I have felt in a very long time (probably 10-15 years). I was averaging about 2-3 hours of interrupted sleep a night. I am now sleeping 4-6 with occasional wakings, to date caused by either mouth breathing or mask leaks, which wake me up. I have trouble breathing through my nose and have for years, but as soon as I put on the CPAP I have no trouble breathing through my nose. I have been turning up the Humidity and that seems to have stopped my mouth breathing, though I think I am going to order a chin strap anyway.

My questions revolve around the numbers I am getting off of my machine. I do not have software or a reader yet, but I know I want to get both, as I don't believe in leaving things to doctors. I know I am my own best advocate. Anyway, I think I understand the AHI, AI and HI readings, but I am very confused by the leak rate things I have read on the boards, so I don't know what to make of the readings.

My AHI during my first sleep study was 132/hr, I don't have the report in front of me and don't recall the AI and HI numbers but I know the vast majority were AI events. I am set up for 14, no EPR and Ramp of 15min.

Here are my readings from the machine for the first 6 nights.


AHI.....AI.....HI...LEAK (L/S) TIME
1. 24.2...4.7...19.5
2. 10.3...1.1...10.3.................6:56
3. 13.7...1.6...12.1.....0.5........4:49
4. 6.4....0.3....6.1.....0.48.......5:45
5. 19.9...1.9...18.0.... 0.44.......7:04
6. 7.0....0.3....6.7.....0.38.......6:07


Nights 4 and 6 were spent mostly on my back and without a pillow, and for what it's worth I still sleep in a water bed (which I dearly love).

So can someone please confirm and / or answer the following:

What I have read indicates that the AHI, AI and HI are number of events per night and not an hour, is this correct?

What are acceptable AHI, AI and HI readings while using your CPAP?

I have read that my machine has been known for having artificially high HI numbers, is this true?

It is my understanding that I should be targeting an AHI less than 5, true?

It is my understanding that the ResMed automatically deducts the normal leak rate for my mask. This means that the remaining leak rate is displayed, correct?

What is an acceptable leak rate?

Can you use the leak rate to explain the high HI readings?

What software is recommended for my machine, and where can I purchase it?

Thanks

your leak numbers are too high which means that AHI (hourly average) may be distorted DOWN not UP so you might be in deep trouble

get the leaks fixed then work on the AHI

jules wrote:your leak numbers are too high which means that AHI (hourly average) may be distorted DOWN not UP so you might be in deep trouble

get the leaks fixed then work on the AHI

I would like to try to understand this. From another post the leak rate for the Swift at 12 cm was reported to be 36.7 L/m, which is over 0.6 L/s. All of the leak rates are less than that, and the pressure's not at 12 cm, it's at 14 cm. So it seems like the leak rates reported are not too high. I may be missing something, which is what I am trying to understand. Maybe someone can help me, if I've got it wrong.

In any event, I would agree that the AHI's reported are generally too high.

never say never wrote:
So can someone please confirm and / or answer the following:

What I have read indicates that the AHI, AI and HI are number of events per night and not an hour, is this correct?

I don't think you've stated it correctly. AHI, AI, and HI are events per hour, as I understand it. Per night would be fairly meaningless when you start comparing one night to another. To find the index, take the total number of events in a night and divide it by the number of hours slept. That will give you the index.

Resmed reports excess leak rate not the actual flow rate in l/sec based on the mask in the menu. They do report the 95 % ile which means 5 % of the night the leak rate is at or in excess of that number. If the OP has a leak rate of say .4 that is 24 l/min in excess of whatever the swift would report at his/her pressure. The numbers they reports were that high.

Respironics reports the flow rate in l/min.

jules wrote:your leak numbers are too high which means that AHI (hourly average) may be distorted DOWN not UP so you might be in deep trouble

get the leaks fixed then work on the AHI

Hi,

I would agree with that observation. I typically see around 0.20 of leak on my Swift LT. Once you have a high leak rate, the rest of the numbers are suspect. The typical goal for AHI is 5. RedMed machines are known for scoring HI's higher than other machines. Some state that you can use AI + HI/2 = AHI as a more realistic level. That means that your numbers on nights 4 and 6 were not too bad, however, I wouldn't trust those numbers due to the leak level. It is a bit unusual to have lower numbers when on your back--most folks see worse numbers on their back.

Feeling better is a good sign that you are making progress. If comfort is an issue, you might want to try some EPR. I have seen 14 used as a guideline as an upper limit to what someone would want on a straight CPAP machine. Above that is often BiLevel territory. EPR sort of acts the same way by dropping the exhale pressure from 1 to 3 points.

A trick that I have learned here is to use a product called Lanisoh on the nasal pillows. That helps make a much better seal around the base of your nose. You can find it in the baby products isle of your supermarket or drug store. But in this case, I suspect that you are losing the air out your mouth. The only useful options that I know of are a chin strap, mouth taping, or a full face mask. I know I didn't do well with a full face mask (I got leaks into my eyes which were really painful), and the chin strap left me very sore. The tape option seems to be working well for me. Your mileage may vary.

Congrats on getting started, and congrats on wanting to do better.

-john-


-john-

jules wrote:Resmed reports excess leak rate not the actual flow rate in l/sec based on the mask in the menu. They do report the 95 % ile which means 5 % of the night the leak rate is at or in excess of that number. If the OP has a leak rate of say .4 that is 24 l/min in excess of whatever the swift would report at his/her pressure. The numbers they reports were that high.

Respironics reports the flow rate in l/min.

Thank you! Now, if only I can remember that tidbit....

LoQ wrote:
Thank you! Now, if only I can remember that tidbit....

Once you have a machine that reports data, you will know which part of that you need to remember for your machine.

If I understand things right the machine I have, Resmed S8 Elite II, will automatically subtract the leak rate for my mask. So I agree that the leak rate is too high, and I think I will get that under control. However, I have read so much conflicting information I don't know what to believe and I have not found a 'source I trust' yet. Hence all the involved questions.

I have the same issue with the AHI, AI and HI numbers on the ResMed S8 I have read that they are nightly counts and NOT an hourly index, again I need to know what is correct so I know where I am, which is why I have such an extensive list of questions.
Keep in mind I do not have any software, and I am getting this information off the display of the ResMed S8, if that makes a difference.

@john
I will see if I can find "Lanisoh" I was wondering what I could safely put on the nasal pillows without deteriorating the silicon.

I can already tell a marked improvement in my sleep, and I am certain that it will continue to improve, especially if I can get my head around these numbers and what they actually mean.

Thanks for the input.

let's look at one of the nights - your pressure is 14, swift uses a flow rate of 40 for swift 2 at 14

http://www.resmed.com/us/assets/documen ... sa_eng.pdf

assume your menu has swift as your mask and that 40 is what the machine thinks your flow rate should be

you had a night with a leak rate of .5 (night 3), so 5 % of that night (you slept 4 hr 49 min - lets say 290 min), ie 14.5 min you machine was sending out at least .5*60 or 30 extra l/min or about 70 l/min.

during that time who knows what was going on - eventually you woke up and fixed the leak

however for the rest of the night - the other 4 1/2 hours plus - you have no idea how much flow the machine was putting out - this is why the software can help - so you can see if that was fluke or if you were high a lot of the night -

while the machine was putting out all that flow who know how many events you were having - the machine sees leak and is blind to apneas

you want Resscan - not sure what version - all depends on what OS and if you have S8, S8 II or S9 and that info isn't in front of me right now and I only know Encore myself

never say never wrote:
I have the same issue with the AHI, AI and HI numbers on the ResMed S8 I have read that they are nightly counts and NOT an hourly index,

a nightly count would be a WHOLE number - no decimals --

First: is your mask defined properly in your Elite? If is is set to STANDARD (assumes mask vent rate of 24), your leak is actually worse than reported. Accept it, you have a huge leak problem to deal with before you can trust the reported numbers. With nasal or pillow mask, you're losing air...likely thru your mouth. I hadda give up my beloved pillow mask when I started losing therapy air via my mouth; I now wear the RespCare Hybrid which combines the comfort of pillows with security of an oral cushion that prevents air from my mouth escaping into the room air. The mask is surprisingly comfortable. Our host sells it for about $100.

The machine's reported numbers are the hourly averages. They take the total number of events and divide it by the hrs of use to get those numbers.