Need Help Interpreting Stats from Machine

I'm having trouble understanding the Leaks in particular and can't quite grasp the difference between AI & AHI events. I notice my leaks Maximum can be anywhere from 2 up to 164 - that's a big variation!
I'm not able to see any detailed data - apparently that's not 'turned on' on my machine, but I do get graphs and reports.
Here's the data from 10/30/10:

Equipment Information
Flow Generator: Flow Generator Serial Number: Owner: Yes
Flow Generator Software Version:
Humidifier: Humidifier Serial Number: Owner: Yes
Data Module: Data Module Serial Number: Owner: Yes
Data Module Software Version:
Mask:
Data Card: No
Statistics
Product: S9 Elite
10/30/2010 - 10/30/2010
Device Settings
Therapy Mode: CPAP Set Pressure: 7.0 cmH2O EPR: Off
EPR Level: 0.0 cmH2O
Pressure - cmH2O
Median: 7.0 95th Percentile: 7.0 Maximum: 7.0
Leak - L/min
Median: 0.0 95th Percentile: 3.6 Maximum: 138.0
AHI & AI - Events/hr
Apnea index: 0.1 AHI: 0.4 Obstructive: 0.0
Central: 0.0 Unknown: 0.1 Hypopnea index: 0.3
Usage
Days not used: 0 Total days: 1 Median daily usage: 7:23
Total hours used: 7:23 Average daily usage: 7:23


Thank you for any help you can give me on this.
Cheers,
Xena

You might want to take a look at the following site to get up to speed with the particulars. It will explain all your questions http://www.osahelp.com/

I will take a stab at this ...

xenablue wrote:...
Equipment Information
Flow Generator: Flow Generator Serial Number: Owner: Yes
Flow Generator Software Version:
Humidifier: Humidifier Serial Number: Owner: Yes
Data Module: Data Module Serial Number: Owner: Yes
Data Module Software Version:
Mask:
Data Card: No
Statistics
Product: S9 Elite
10/30/2010 - 10/30/2010
Device Settings
Therapy Mode: CPAP Set Pressure: 7.0 cmH2O EPR: Off
EPR Level: 0.0 cmH2O
Pressure - cmH2O
Median: 7.0 95th Percentile: 7.0 Maximum: 7.0
...

Just tells us information about your machine. It is set in CPAP mode at 7.0cm H2O.

xenablue wrote:...
Leak - L/min
Median: 0.0 95th Percentile: 3.6 Maximum: 138.0
...

This tells us that most of the time (the 95th percentile), the leak rate was 3.6 Liters per minute (L/min). That's not bad. The maximum measured was 138 L/min. That was probably when you removed the mask and the machine was still running. Not a problem.

That leak rate (3.6 L/min) is probably not a big deal with the S9.

xenablue wrote:...
AHI & AI - Events/hr
Apnea index: 0.1 AHI: 0.4 Obstructive: 0.0
Central: 0.0 Unknown: 0.1 Hypopnea index: 0.3
...

Your Apnea Hypopnea Index (AHI) is 0.4. That means during the time you used your machine you had less than one apnea and hypopnea per hour. Take the total number of apneas (when you cease breathing to 10 seconds or more) and hypopneas (restricted airflow for 10 seconds or more) and divide the total by the number of hours and that yields the AHI value.

An AHI of 0.4 is quite low and a good sign the therapy is working for you.

xenablue wrote:...
Usage
Days not used: 0 Total days: 1 Median daily usage: 7:23
Total hours used: 7:23 Average daily usage: 7:23
...

And this notes how low you used it. Since this is for one day the average is 7 hours and 23 minutes. As you use it longer the total numer of hours will increase.

Slartybartfast wrote:You might want to take a look at the following site to get up to speed with the particulars. It will explain all your questions http://www.osahelp.com/

Thanks SlartyBF - I was hoping for some more reading material, just never quite sure where the best places are to go.

Cheers,
Xena

JohnBFisher wrote:I will take a stab at this ...

Many thanks, John - this explains it very clearly. I was wondering why the huge variation in Maximum leaks, so ripping off the mask in disgust is recorded.... hmmmmm

Cheers,
xena

xenablue,

Your signature indicates that your machine is an ResMed S9 Auto, which is the same as my machine, and that your mask is a mirage liberty full face, which I am not using. So my answers are based on what I know about my machine.

In particular you write:

xenablue wrote:I'm having trouble understanding the Leaks in particular and can't quite grasp the difference between AI & AHI events.

The S9's software detects four types of respiratory events: Obstructive apneas, central apneas, unknown apneas, and hypopneas. The unknown apneas are events that the S9's algorithm detects as apneas, but cannot tell whether the apnea is obstructive or central with enough certainty to classify them.

The AHI number is the Apnea/hypopnea index for the reporting period, which on the S9 LCD is typically the overnight number. The AHI is computed by the S9 as follows: It takes the number of all detectable events (obstructive apneas, central apneas, unknown apneas, and hypopneas detected) and divides that number by the time the machine was running. The LCD display number is simply truncated at one decimal place without any rounding as near as I can tell.

The AI number is the Apnea index for the reporting period. It only counts the obstructive, central, and unknown apneas. In other words, the S9 computes this number by dividing the number of detected apneas (includes obstructive, central, and unknown apneas) by the time the machine was running. Again, the LCD display number seems to simply be truncated at one decimal place instead of being rounded to one decimal place.

An example might help. Suppose that on a given night the S9 detects 15 total events---lets say there are 9 obstructive apneas, 2 central apneas, and 4 hypopneas---and that the machine was run for a total of 6.6 hours.

The LCD's numbers are computed as follows:

AHI = 15/6.6 = 2.272727 = 2.2 (due to truncating the decimal)
AI = 11/6.6 = 1.666667 = 1.6 (due to truncating the decimal)
CAI = 2/6.6 = 0.303030 = 0.3 (due to truncating the decimal)

I notice my leaks Maximum can be anywhere from 2 up to 164 - that's a big variation!
I'm not able to see any detailed data - apparently that's not 'turned on' on my machine, but I do get graphs and reports.

If you're able to get the graphs and reports in ResScan, then I believe Sleep Quality has been turned ON. But even the "detailed" information on the LCD is not that detailed compared to what you get in ResScan. But maybe you're having trouble getting the "detailed" LCD information? Here's how to do it:

Step 1) Press the info button on the S9 to get into the short Sleep Quality menu.

Step 2) Hold both the info and the double check buttons down at the same time for three seconds or so. You may notice a brief flash.

Step 3) Use the large round knob to scroll down ONE icon on the left hand list of icons. You should now see the top of the detailed Sleep Quality menu. And then CLICK the round button to select the detailed Sleep Quality menu. This will now let you scroll all the way through the detailed Sleep Quality menu to see the AHI, AI, and CAI, which are at the bottom of this menu. It will also allow you to change the data period from 1 Day to 1 Week to 1 Month to 3 Months to get an idea of the averages of the data over longer time frames than over night.

Here's the data from 10/30/10:

Is the data you report from ResScan or the directly from the S9?

Equipment Information
Flow Generator: Flow Generator Serial Number: Owner: Yes
Flow Generator Software Version:
Humidifier: Humidifier Serial Number: Owner: Yes
Data Module: Data Module Serial Number: Owner: Yes
Data Module Software Version:
Mask:
Data Card: No

If you don't have a data card in the machine, how are you downloading the detailed graphical information into ResScan?

Statistics
Product: S9 Elite
10/30/2010 - 10/30/2010
Device Settings
Therapy Mode: CPAP Set Pressure: 7.0 cmH2O EPR: Off
EPR Level: 0.0 cmH2O

This says that your machine is running in straight CPAP mode at 7cm of pressure and that EPR is set to OFF.

Pressure - cmH2O
Median: 7.0 95th Percentile: 7.0 Maximum: 7.0

Since your machine is in straight CPAP, the median, 95%, and maximum pressures are all 7cm because in straight CPAP, there are no pressure changes.

Leak - L/min
Median: 0.0 95th Percentile: 3.6 Maximum: 138.0

Your median leak rate is 0.0 L/min. So 50% of the time the machine was running on the night of October 30-31, the S9 could detect no mask leaks above and beyond what it expects from your mask provided your mask setting is correct.

Your 95% percentile leak is 3.6 L/min. SO 95% of the time the machine was running, the S9 was detecting leaks with a leak rate of LESS THAN or EQUAL TO 3.6 L/min. That's probably a pretty decent leak rate. Since you later list Usage as 7:23 [7 hours and 23 minutes], which is about 7.3 hours, you can interpret the 95% leak rate as follows:

In the 7 hours and 23 minutes the machine was running, the leak rate was GREATER THAN 3.6 for a total of about 22 minutes. [5% of 60 minutes is 3 minutes; so 5% of 7.3 hours is 7.3 x 3 = 21.9 minutes]

Your maximum leak was a whopping 138.0 L/min. But note that this might simply be a very short lived "leak" triggered by you taking the mask off before turning the S9 off. Or some other very large leak. In order to figure out what/why you had such a large leak, you need to look at the detailed leak data graph. But since the 95% leak rate is low, you already know that this major leak was not a really, really long one.

AHI & AI - Events/hr
Apnea index: 0.1 AHI: 0.4 Obstructive: 0.0
Central: 0.0 Unknown: 0.1 Hypopnea index: 0.3

Again, since your usage was about 7.3 hours, I can estimate the number of events you had and what type they were from the AHI, AI, CAI, Unknown I, and HI indices as follows:

Total number of apneas and hypopneas:
AHI x Usage = (0.4 events per hour) x (7.3 hours) = approx. 2.92 events = 3 events (round UP since there's a fraction)

Total number of apneas (all types):
AI x Usage = (0.1 apneas per hour) x (7.3 hours) = approx. 0.73 apneas = 1 apneas (round UP since there's a fraction)

Total number of obstructive apneas:
OAI x Usage = (0.0 OAs per hour) x (7.3 hours) = 0.0 obstructive apneas

Total number of central apneas:
CAI x Usage = (0.0 CAs per hour) x (7.3 hours) = 0.0 central apneas

Total number of unknown apneas:
Unknown I x Usage = (0.1 Unknown apneas per hour) x (7.3 hours) = 0.73 unknown apneas = 1 unknown apnea (round UP since there is a fraction)
NOTE: An "unknown apnea" is one that the S9 can't classify as either an obstructive one or a central one based on the data it has)

Total number of hypopneas:
HI = Usage = (0.3 Hypopneas per hour) x (7.3 hours) = 2.19 hypopneas = 2 or 3 hypopneas over night based on estimate of 3 total events, one of which is an unknown apnea.

Usage
Days not used: 0 Total days: 1 Median daily usage: 7:23
Total hours used: 7:23 Average daily usage: 7:23

This simply says that in the one day period you're looking at (10/30/2010 to 10/30/2010), you used the S9 for 7 hours and 23 minutes.

Hope this helps.
robysue

robysue,
Well... what the heck???? I have an S9 Elite - I'm thinking I clicked the wrong thing when I changed my mask. Thanks for pointing this out.
Thanks so much! That is great info, even though I had the wrong machine, I'm presuming the Elite works the same way.
I have the software so plug the SD card into the reader at my computer and that's where those stats came from.

Hugs,
xena

xena,

Yes, the S9 Elite is a full data machine and except for not having an APAP mode, it is very similar to the S9 AutoSet. In particular, the S9 Elite reports data in the same way that the S9 AutoSet does.

Good luck in learning how to get at the data.

robysue wrote:xena,

Yes, the S9 Elite is a full data machine and except for not having an APAP mode, it is very similar to the S9 AutoSet. In particular, the S9 Elite reports data in the same way that the S9 AutoSet does.

Good luck in learning how to get at the data.

Thanks! I saw your post on the other thread also. I haven't been able to access detailed graphs at all - when I open Rescan it says something about it not being turned on, but I'll try your suggestions and see if that works.

Hugs,
Xena

xena,

Love your avatar.

Noticed your location as "an aussie living in balmy wisconsin"

I spent part of my childhood in Appleton, WI before moving to VA in 6th grade. Have you been through a WI winter yet?

robysue wrote:xena,

Love your avatar.

Noticed your location as "an aussie living in balmy wisconsin"

I spent part of my childhood in Appleton, WI before moving to VA in 6th grade. Have you been through a WI winter yet?

robysue, this will be my 13th Wisconsin winter and I LOVE IT!! I'm in Milwaukee and whilst I love the snow I AM tired of the single other season here - ROAD CONSTRUCTION.