0.6 AHI, but mean-pressure = min pressure

0.6 AHI, but mean-pressure = min pressure - Printable Version

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0.6 AHI, but mean-pressure = min pressure - Visitor - 06-24-2014

Is this normal? Feeling great, but I'm puzzled that the mean pressure = min pressure. Graphs look nearly flat as a result. Should be good right? (third line counting from bottom, marked in dark blue)

[Image: 28txgro.jpg]

RE: 0.6 AHI, but mean-pressure = min pressure - robysue - 06-24-2014

The image looks like an Excel spreadsheet of numbers. What do the acronyms in the column labels stand for?

What graph are you talking about?

And I can't figure out how or where the "mean pressure" value you are talking about is being computed.

Question: Is the mean pressure being computed from values used to draw the pressure graph? And are you sure you are looking at the mean pressure instead of the median pressure?

RE: 0.6 AHI, but mean-pressure = min pressure - zonk - 06-24-2014

(06-24-2014, 01:49 AM)robysue Wrote: And I can't figure out how or where the "mean pressure" value you are talking about is being computed.

I,m not sure either, Visitor posted some graphs here (see post #7):
http://www.apneaboard.com/forums/Thread-Data-how-am-I-doing

RE: 0.6 AHI, but mean-pressure = min pressure - Visitor - 06-24-2014

Thanks, I will post the other graphs and will indicate what the abbreviations stand for.

RE: 0.6 AHI, but mean-pressure = min pressure - retired_guy - 06-24-2014

What's clear about the chart is your doing great, Visitor! Look at what the AHI has been doing (right-most column) Each day it has been dropping as you have been using the machine. You're staying nicely within your min/max range, and not making a lot of changes from one day to the next.

AHI of .06? That's great. Keep up the good work.

RE: 0.6 AHI, but mean-pressure = min pressure - Visitor - 06-24-2014

Great,

P = mean pressure, L = mean leakage, index of abnormal respiration, as a percentage of total therapeutic time (ARDI).

Rest is clear (or unknown)

Also:

Recommended mask leakage: 20 to 40 litres per minute at 10 cmH2O
(min mask leakage 12 l/min at 4 cmH2O)

here are the graphs:

[Image: muvp6h.jpg]

RE: 0.6 AHI, but mean-pressure = min pressure - PsychoMike - 06-24-2014

Visitor, I'm in almost the same boat.

My pressure has been tweaked a little over the last few months and my current mean pressure is only slightly higher than my current minimum pressure. In my books, it is what it is...my body likes it (AHI in the 0.15 or lower range), the mask likes it (mean leaks are practically zero) and I'm getting good sleep. Heck, my "short" nights leave me feeling better now than my long nights before treatment did. Enjoy it Smile

RE: 0.6 AHI, but mean-pressure = min pressure - Visitor - 06-24-2014

Interesting PsychoMike, I'm definitely feeling good. No clue if there are central apneas (based on these graphs).

RE: 0.6 AHI, but mean-pressure = min pressure - robysue - 06-24-2014

(06-24-2014, 11:13 AM)Visitor Wrote: Great,

P = mean pressure, L = mean leakage, index of abnormal respiration, as a percentage of total therapeutic time (ARDI).

What program is computing the "mean pressure" for you? And are you sure you are not misreading "median pressure" as "mean pressure"?

The graphs you post look like they are from the official software for your Breas iSleep 20i machine. The pressure data makes it clear that the median pressure for this night is indeed equal to your minimum pressure setting because the machine left the pressure at its minimum setting for at least 70-75% of the night.

And given the very minor pressure increases and how short lived they are, I would expect the (weighted) mean to be pretty close to the minimum pressure setting. And it's possible that if the mean pressure is rounded to one decimal place that it looks just like the minimum pressure setting.

For example, suppose we have 1000 data points, and 950 of those data points are equal to 6.5 and the remaining data points are all equal to 7. Then the mean of the set is:

(950 * 6.5 + 50 * 7)/1000 = (6175 + 350)/1000 = 6525/1000 = 6.525 = 6.5 when the data is rounded to one decimal place

RE: 0.6 AHI, but mean-pressure = min pressure - Visitor - 06-24-2014

Makes sense.