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I am most familiar with Most of the focus in this article is on how the daily data looks for ResMed and PR machines. So I focus on those machines in this post, but much But most of what I write it still applies to the data SleepyHead shows for any of the machines that it supports.
I am also going to try to restrict myself This article is primarily restricted to the most basic, important data for a newbie to concern themselves with. This post reflects my own tastes in what data I tend to pay attention to on a regular basis. As a mathematician, I have a strong preference for The focus is mainly upon the graphical data in the Daily Data window.
I use The example patient uses a BiPAP and that's why I have there is both an IPAP and and EPAP line. I The patient also use uses a PR machine, so that's why I have there is both Leak and Total Leak data. Users of a S9 Elite or AutoSet will see both lines for both pressure and EPAP, where the EPAP data equals Pressure - EPR. ResMed users will NOT have a line for Total Leak data since the S9 records only the unintentional leak data.
In this post I want to concentrate on which First a screen shot of the preferred set up of the daily graphs are important, what information they convey, and how they are related to each other.:<br />
First a screen shot of my preferred set up of the daily graphs:<br />
I have In this example, the Redline option turned OFF because I know my the patient knows her leaks well enough to know that an official Encore LL is going to be scored only if the Total Leak Rate is up near 60 L/min.
This graph is often misunderstood by many new PAPers And because of that, I tend to recommend that new SleepyHead users just ignore this graph.
→Basic data interpretation: Daily Detailed Data: NPOV & Cleanup
The amount of data available in SleepyHead can be overwhelming to new PAPers, particularly those who only want some reassurance that "things are working." While many newbies tend to focus on the data in the Statistics tab and the Overview tab, the data in the Daily tab is usually more useful when you are trying to analyze what's going well and what's not going so well during the CPAP adjustment period. Moreover, the Daily Detailed Data is currently more robust and less buggy than the data presented in the Statistics tab. So I would encourage new SleepyHead users to first concentrate on getting comfortable with their detailed Daily data. Even so, you want to look at the detailed Daily data in context: One bad night does not mean things are suddenly not working; a month of bad nights does indicate something is wrong.
'''Left Side Bar data---AHI and event data table'''
<br />
The single most important piece of numerical data is the AHI data. The goal of PAP therapy is to keep the AHI down below 5 night after night after night ...
If your AHI looks good and your leak data is acceptable, then the PAP machine is doing its job. Whether that's enough to make you feel great is another issue, but the machine '''is ''' doing its job.
Under the AHI banner we see the indices for all the various types of "events" that might be recorded during the night. In other words, the line that says
In general the advice people will offer you about what to do about an AHI that is too high will depend on what the OAI and CAI look like.
'''
NEW in SleepyHead 0.9.6: Large Leak Summary Data'''
For PR System One users, if you have any official Large Leaks, SleepyHead 0.9.6 will report the percentage of time spent in Large Leak territory with the other summary event data. This should make it easier for PR System One users to figure out whether their leaks are are significant enough to adversely affect therapy.
Percentage time in Large Leak for users of other machines will NOT appear with the AHI data above the pie chart.
The '''pie chart''' at the end of the index data gives a quick visual impression of what kind of events were most common. On this night I the patient had far more FLs than any other kind of scoreable event.
'''Note:''' ResMed machines record the snore data and flow limitation data as a continuous graph, so there will be NO snore data or flow limitation data on this table. RERAs are only scored by PR System One machines.
''
IMPORTANT NOTES about PR System One machines:''<br />
Vibratory Snore (index) = (number of VS1 scored)/(run time)
The thing is: VS1 snores are scored on a PR machine only if the machine is running in Auto mode. If you are using a PR machine in fixed pressure mode, the SleepyHead 0.9.3 Vibratory Snore index will always be 0.0; but that does NOT imply that you are '''not ''' snoring.
'''2)''' ''The Flow Limitation data is recorded on a PR machine '''only if''' the machine is running in Auto mode.'' If you are using a PR machine in fixed pressure mode, the Flow Limitation index will be 0.0; but you can't assume that means you are not having any flow limitations.
'''
Left Sidebar Data---Statistical Data chart'''
This is located directly below the Pie Chart. Let's look at it more closely:<br />
<br />
<br />
Med (Median) and 90% (or 95%) are statistical terms. The '''median''' value for a given set of data is the halfway point: Half the data is AT or BELOW the median value; half the data is AT or ABOVE the median value. The 90% value is the data value for which 90% of the data is AT or BELOW the value and 10% of the data is AT or ABOVE the value. Both Median and 90% are explained very carefully in my a blog post [http://adventures-in-hosehead-land.blogspot.com/2012/03/average-median-95-numbers-guide-to.html Average, Median, 95% numbers: A guide to those who don't remember their introductory stats]
Of all the numbers in this table, the most important ones are the Pressure numbers and the Leak and Total Leak numbers. All the other numbers in this table can safely be ignored.
The EPAP line of the table looks like:
'''EPAP 4.00 4.00 4.00 5.00'''
This means that my minimum EPAP =4, my median EPAP = 4, my 90% EPAP = 4, and my max EPAP = 5. What this tells me us is that my the EPAP stayed at 4cm for at least 90% of the night. But my the EPAP did get as high as 5cm at some point during the night.
The IPAP line of the table
'''IPAP 6.00 6.00 8.00 8.00'''
means that my minimum IPAP = 6, my median IPAP = 6, my 90% EPAP = 8, and my max IPAP = 8. That means that my the IPAP stayed at 6cm for at least 50% of the night and my the IPAP was LESS THAN or EQUAL to 8 cm for 90% of the night. From this data, we can't tell if my the IPAP = 8 for almost 50% of the night or if my the IPAP = 8 for only about 10-15% of the night.
'''Statistical Leak Data'''
The most important data in statistical data is the Leak data. Because I use the patient uses a PR System One, there are two lines of leak data and they look like this:
'''Leak Rate 0.00 0.00 10.00 14.00
Total Leaks 11.00 14.00 23.00 34.00'''
The '''Leak Rate''' numbers are SH's statistical "guess" about what my '''unintentional''' leak rate is. This number is NOT an official Encore number and it does not come directly from the data on my the SD card; it is calculated from the Total Leak rate data that is recorded on the SD card.
The '''Total Leaks''' line is the statistical summary of the (raw) leak data. In some sense this may be more trustworthy for people using machines that record total leaks.
And the meaning of the numbers? My The patient's median (unintentional) leak rate is 0.0 L/min, my their 90% (unintentional) leak rate is 10.00 L/min, and my their maximum (unintentional) leak rate is 14.00 L/min. This means:
* For at least 50% of the night, my the unintentional leak rate was 0.0 L/min; in other words for at least 50% of the night, I the patient had no detectable unintentional leaks* For 90% of the night my the leak rate was at or BELOW 10.00 L/min and for at most 10% of the night my the patient's leak rate was ABOVE 10.00 L/min* Since my the maximum leak rate was 14 L/min, I we know that for at most 10% of the night my the patient's leaks were between 10 L/min and 14 L/min.
These Leak numbers are pretty good numbers for a PR System user.
The Total Leak numbers confirm that my the patient's leaks are pretty well under control: My The minimum total leak rate was 11.00 L/min; my the median total leak rate was 14.00 L/min; my the 90% total leak was 23.00 L/min; and my the maximum total leak rate was 34.00 L/min. At the pressures I use used by the patient, the expected leak rate for my their mask is about 20-29 L/min. So these numbers look very good: For 90% of the night my the patient's total leak rate was AT or BELOW 23 L/min, which is right around the expected leak rate for my their mask.
'''NEW in SleepyHead 0.9.6: Time over leak redline'''
If you use a PR System One or a ResMed S9, SleepyHead will show you the percentage of time your leaks were in Large Leak territory for your machine. This will help you evaluate whether or not your excess leaks are both large enough and long enough to adversely affect your therapy. A small amount of time in Large Leak territory can be ignored if your leaks are under control for most of the night; a large amount of time in Large Leak territory cannot be ignored.
The question, of course is how : How much time in Large Leak territory is too much? ResMed provides a guideline for its users: Mr. Red Frowny face shows up on the Sleep Quality Report if your leaks are above the Redline for at least 30% of the night. When the Large Leaks last that long, ResMed's engineers believe both efficacy of the PAP therapy and the accuracy of the recorded data can be adversely affected. We will assume that 30% of the night in Large Leak territory is clearly bad news for users of any PAP machine. But many people may find that their therapy begins to be compromised by the time Large Leaks make up 20% of the night. For a lot more information on leaks, see [http://www.apneaboard.com/wiki/index.php?title=Beginner%27s_Guide_to_SleepyHead#Leaks 8. Leaks].
If you are using a DeVilbiss IntelliPAP or an Fisher & Paykel Icon or if you are using SleepyHead 0.9.3 or earlier, then you will need to use the median and 90% (or 95%) Leak/Total Leak data to evaluate your leaks.
In order to make sense of the statistical numbers shown on the Leak Rate and Total Leaks lines, you need to know how the manufacturer of your machine defines Large Leak. Information about how ResMed, Fisher & Paykel, DeVilbiss define '''''Large Leak''''' can be found in [http://www.apneaboard.com/wiki/index.php?title=Beginner%27s_Guide_to_SleepyHead#Leaks 8. Leaks]. PR does not have a published "line" for defining Large Leak on the System One machines, but there are patterns that have been noticed in the PR data. That information is also talked about [http://www.apneaboard.com/wiki/index.php?title=Beginner%27s_Guide_to_SleepyHead#Leaks 8. Leaks].
In general:
If your '''90% (or 95%)''' Leak or Total Leak data is well under the official Large Leak definition for your machine, but the '''maximum''' Leak or Total Leak data is over the Large Leak line for your machine, then you have a few, probably short lived Large Leaks. At most your leak was in Large Leak territory for no more than 10% (or 5%) of the total night. Unless all the time in Large Leak territory is in one prolonged Large Leak, chances are your Large Leaks are NOT '''''long enough''''' to have an adverse affect on your therapy.
If your '''median''' Leak or Total Leak data is well under the official Large Leak definition for your machine, but the '''90% (95%)''' Leak or Total Leak data is near or over the Large Leak line for your machine, then you may have a leak problem that is both '''large enough''' and '''long enough''' to adversely affect your therapy. On the one hand, we know that your leak was NOT in Large Leak territory for at least 50% of the total night. But the numbers alone don't tell us if you were in (or close to) Large Leak territory for only 10-15% of the night or if you were in (or close to) Large Leak territory for 45% of the night. You really need to examine the leak graph to figure out what's going on. More on that later in this post.
If your '''median''' Leak or Total Leak data is close to or above the official Large Leak definition for your machine, then you definitely have a problem with Large Leaks. You are leaking at a very high and significant rate for at least 50% of the night, and that definitely means that the leaks are both '''long enough''' and '''large enough''' to adversely affect your therapy and the accuracy of your data.
The machine you are using will determine exactly which graphs will show up in your Daily Data. But the most important graphs will be present in every machine's data.
In SleepyHead you can temporarily hide unneeded graphs so that they're not in your way; resize graphs so that more of them fit on your screen; and rearrange the graphs so that you can group the graphs you want to look at together. You can also pin selected graphs to the top of the Daily graphs section so they do not scroll out of view. You can also zoom in on particular parts of the data where there is a lot of activity so that you can get a better idea of what might be going on at night. Instructions on how to do all these things can be found in [http://www.apneaboard.com/wiki/index.php?title=Beginner%27s_Guide_to_SleepyHead#Manipulating_Daily_and_Overview_Graphs 13. Manipulating Daily and Overview Graphs]. This article concentrates on which graphs are important, what information they convey, and how they are related to each other.
[[File:daily-graphs_zpscf0763d4.jpg]]
<br />
'''The Pressure graph'''
The Pressure graph shows the therapeutic pressure level throughout the night. Because I'm using this particular patient uses a PR BiPAP, the IPAP and EPAP graphs vary independently of each other. The IPAP is the top graph; the EPAP is the lower graph. ResMed Elite and AutoSet users will have two pressure graphs if they have EPR turned on. The top graph is the Pressure setting; the bottom graph, which is label EPAP, shows what EPAP = Pressure - EPR looks like.
If you are using your PAP in fixed pressure mode, the pressure graph is not of much use---unless you are spending a lot of time hitting the ramp button. But if you are using your PAP in Auto mode, the pressure curve tells you when the machine raised the pressure and how much it raised the pressure. Comparing the pressure increases with the events flagged in the Flow Rate curve or the Events Table can give you some very good ideas about why the machine decided to increase the pressure and also give you a sense of whether the disordered breathing got better or worse with the pressure increase.
This graph shows both the Total Leaks (light gold color on top) and the SH calculated (unintentional) Leaks (purple on bottom) because I'm using a PR System One. A ResMed user is only going to see the purple Leaks graph.
This is not my the patient's best leak line, but it is a perfectly acceptable leak line for a PR System One BiPAP with IPAP = 8 and EPAP = 4 or 5.
Looking at the Leak graph will allow you to see just how long your worst leaks lasted and just how big they were. When the leak graph looked at along with with the statistical leak data in the Left Sidebar, you can get a very good idea of whether leaks may be adversely affecting your therapy. If you have a wide Auto range, you can track whether increases in pressure are leading to increased unintentional leaking. And when the leak rate is in Large Leak territory, you can often see how the Large Leak affects the ability of the machine to track the breathing, and how that affects the accuracy of the AHI data.
'''Two other ''potentially'' important graphs'''
The '''Snore graph''' is sometimes useful to look at, even though no-one knows just what the y-axis numbers actually mean. The reason its useful is that snore graph can sometimes explain a pressure increase when there seems to be nothing unusual going on in the Flow Rate graph.
For ResMed S9 users, the Flow limitation graph is sometimes useful to look at because it can explain a pressure increase in the absence of both snoring and events. High spots on the Flow limitation graph typically correspond to some pretty distorted looking inhalations in the Flow Rate graph.
''
NOTE about Flow Limitation data:'' The PR machines score FL in a very different way than the ResMeds do, and this means there is no FL graph for a PR machine.
'''ALL OTHER GRAPHS'''
All the other graphs (the Respiratory Rate, the Tidal Volume, the Minute Ventilation, and so on and so forth) can be ignored by newbies. If there's something really odd in your Flow Rate data, a more experiences forum member may ask you for one of these graphs on occasion. If you're a real data junkie, you may find these graphs ''interesting'', but they usually do not provide much help in figuring out what might be wrong when a newbie is in trouble. These graphs will be discussed in some future post ...later.
<br />
'''The Event Table---a detailed look'''
The Event table gives a snapshot of how good or bad the whole night was, and whether certain parts of the night were much uglier than the overall AHI might indicate. Compare these two event charts:<br />
[[File:event-charts_zpsd5714439.jpg]]
<br />
You don't need the actual AHI numbers to see that the first night was a lot worse than the second. On the second night, there are only three "events" scored all night: Two CAs and one H. There are a few Flow Limitations, which are common in my this patient's data), but even the FL are well spaced. And the bit of snoring at the beginning of the night is not a real issue. Overall, this night's efficacy data is really quite good.
But on the first night, there are a lot more tick marks over all AND between 4:15 and 5:30 there are a lot of OAs, Hs, and CAs scored. There's a second smaller cluster of events around 8:30 as well. The other thing we can immediately see about the first night is that outside of the 4:15-5:30 and 8:30-9:00 time frames, the rest of the night was pretty good.
'''The Flow Rate graph---a detailed look'''
'''NOTE''': ''Only ResMed S9, PR System One, and F&P Icon machines record Flow Rate data; if you are a DeVilbiss IntelliPAP, you will not have a Flow Rate graph when you look at your data in SH''
<br />
<br />
Different information is conveyed by different levels of "zoom" in the Flow Rate graph. More information on the Flow Rate graph can be found in [http://www.apneaboard.com/wiki/index.php?title=Beginner%27s_Guide_to_SleepyHead#Beyond_AHI:_Apneas_and_hypopneas_in_the_Flow_Rate_graph 9. Beyond AHI: Getting specific information about events].
For now I'll just we will give the following broad guidelines about looking at the Flow Rate graph at differing zoom levels:
These comments apply to ALL the Detailed Daily Data graphs except for the Event Table, but for the most part, you need these tips when you're examining the Flow Rate graph.
'''1)''' Zooming and unzooming. : You can zoom in on the center of the Flow Rate graph by LEFT clicking when the mouse is over the Flow Rate graph. You can zoom back out by RIGHT clicking when the mouse is over the Flow Rate graph.
'''2)''' Scrolling through a Flow Rate graph. : Regardless of how far you have zoomed in on the Flow Rate data, you can scroll through the Flow rate graph by holding the RIGHT mouse button down while moving the mouse in a horizontal direction.
'''3)''' Glitches : Sometimes you run into a SH glitch and the y-axis for the Flow Rate graph is off: The middle part of the breathing cycle is not graphed at 0 L/min. It's a known problem. If this happens to you, the easiest thing to do is just to mentally draw the 0.0 L/min line half way between the peaks and valleys in the Flow Rate graph and use that to measure when you are inhaling and exhaling.<br />
If you use a CPAP or APAP that is NOT a ResMed S9 Elite or S9 AutoSet, you will only see one pressure curve. If you use a bi-level device OR a ResMed S9 Elite or S9 AutoSet, you will see two curves. The top curve is the IPAP---the pressure setting for inhalations; the bottom curve is the EPAP---the pressure setting for exhalations. (The reason the S9 Elite and AutoSet have two pressure curves is that when EPR is on, the machine acts very much like a bi-level.)
If you are using your PAP in '''fixed pressure mode''', the Pressure graph will be a flat line after the ramp period is over. Hence the Pressure graph provides no useful data and can be ignored. So for this section, I we will presume that you are using an auto adjusting machine and that it set to Auto mode.
The primary data you can get off the pressure curve is information about what the machine thinks your pressure needs seem to be for the night. Looking at the Pressure graph and the Flow Graph together allows you to see just how the machine responds to your sleep apnea each and every night. (On a ResMed S9 AutoSet, you might also need to look at the Snore graph and the Flow limitation graph as well.)
'''
Common concerns that people have about their Pressure graph'''
Most concerns and questions people tend to ask about the Pressure graph are really about the Pressure graph relates to other parts of the data. Here are some common things people ask about concerning the Pressure graph.
'''Question:''' ''I had an OA and the machine didn't increase the pressure. Why didn't it increase the pressure to blow through the event and open my airway and end the apnea?''
'''Answer:''' While APAPs and Auto bilevels bi-levels are designed to respond to OAs with pressure increases, they are NOT non-invasive ventilators and they CANNOT trigger inhalations. (The fancier ASV machines ARE non-invasive ventilators and can trigger inhalations).) If the machine is going to increase the pressure in response to an OA, it will wait until the OA is over and you are breathing again before it increases the pressure.
Moreover, the auto -algorithms are designed to NOT respond to isolated OAs and Hs: Unless two or more events happen relatively close to each other (as in within about 2 minutes of each other), an APAP or Auto bi-level machine is programmed to NOT increase the pressure. Here's an example of a 20-second OA that my a patient's BiPAP Auto ignored on a recent night:<br />
[[File:isolated_apnea_zpscf3f0501.jpg]]
<br />
You'll note that the machine had been decreasing the IPAP pressure (since my the breathing was stable) for several minutes before the OA occurred. Neither my the patient's EPAP (which is at its minimum value) nor the their IPAP is increased for this particular OA because it's isolated. There's not another OA or H within 2 minutes of this particular OA.
The fact that APAPs and auto bi-levels do not respond to isolated OAs and Hs seems counter -intuitive to many new PAPers. But this lack of response is intentional and it mimics the [http://www.aasmnet.org/Resources/clinicalguidelines/040210.pdf AASM Clinical Guidelines for Manual Titration Sleep Studies]. The idea is not to jack up the pressure every time any event happens: That can lead to more unstable breathing, discomfort, and more pressure than is needed to keep the airway open most of the time.<br />
'''Question''': Why is my pressure increasing when there don't seem to be any events?
'''Answer''': APAPs (and Auto bi-levels) increase pressure in response to OAs, Hs, snoring, and flow limitations. The PR System One APAP and BiPAP Auto also increase pressure in response to RERAs. The PR System One also has a "search" routine built into its Auto algorithm, and it will periodically increase the pressure as a "test" to see if the shape of the wave flow improves, even if nothing is being scored. Those test increases show up as saw tooths -teeth on the pressure curve. On ResMed machines, the most likely cause for a pressure increase without any events is probably snoring or flow limitations. Here's a picture of a increase in pressure on a ResMed VPAP in response to nothing but flow limitations:<br />
[[File:pressure_increases_zps4dbeba44.jpg]]
On the other hand, the minimum pressure needs to be high enough where the machine does not need to increase the pressure by a significant amount during the first cluster of events. Sharp rapid increases of 5-8 cm of pressure in 10 minutes might not allow the airway enough time to stabilize and settle down. And unstable breathing can cause further events, which leads to more pressure increases and more unstable breathing.
And then to muddy the waters even further: Approximately 10-15% of PAPers may have a tendency to develop pressure -induced central apneas if the pressure setting is too high. And what "too high" ''is '' strongly depends on the individual. And while our modern machines have algorithms to distinguish central apneas from obstructive ones, those algorithms are not perfect, and there is some evidence that the algorithms may be more likely to mis-score CAs as OAs when the CAs occur at relatively higher pressures.
So blindly increasing your pressure just because the machine is running at or near your maximum setting all night long is not a good idea. Before you decide to change your pressure settings, you really need to do some careful thinking about what you hope to accomplish by changing the pressure and have a plan on how to evaluate whether the change does what you intend it to do. And keep in mind that it really is a good idea to consult your sleep doc doctor about any changes to your therapeutic settings.<br />
'''The Leak Rate graph---a detailed look'''
ResMed machines report only the excess leak rate, which is simply called '''Leak''' in the SleepyHead leak data. A ResMed user will see only one leak graph in the Leak Rate graph.
All other major brands of data-capable PAPs report ''Total Leaks'', which include both the intentional leak rate for your mask at your pressure AND the excess leaks. In other words:
''Total Leak = Intentional Leak + Excess Leak''
'''Defining Large Leaks'''
Different manufacturers have different definitions of what Large Leak means for their machine. But for all brands of machines, the idea is that if your leaks are under the manufacturers Large Leak definition, the machine should be able to gracefully compensate for the leaks and deliver effective therapy and accurate data. Information about how ResMed, PR, F&P and DeVilbiss each define '''''Large Leak''''' can be found in [http://www.apneaboard.com/wiki/index.php?title=Beginner%27s_Guide_to_SleepyHead#Leaks 8. Leaks].
'''Tools to help identify Large Leaks: Show Leak RedLine'''
If the manufacturer of your machine has a published Large Leak definition, you can use the Show Leak Redline option to draw a Red Line on your Leak/Total Leak graph to make it easy to spot when the leaks are high enough to be considered Large Leaks. The Show Leak Redline option is talked about in [http://www.apneaboard.com/wiki/index.php?title=Beginner%27s_Guide_to_SleepyHead#Important_preferences_settings 7. Important "preferences settings"].
A typical SH 0.9.6 Leak graph from an S9 VPAP Auto that shows a night with one long leak that is in or near Large Leak territory is shown below. It's worth noting that the amount of time with the leak rate AT or ABOVE 24 L/min is only about 40 minutes and the total run time for the night was about 8.5 hours; hence Mr. Green Smiley Face showed up the next morning on the S9's LCD.<br />
'''Tools to help identify Large Leaks: Large Leak shading for PR System One machines'''
For users of PR System One machines, SleepyHead 0.9.6 will use the Encore Large Leak data to identify parts of the Flow Rate curve that are earmarked as occurring during Large Leaks. The Large Leak will also show up on the LL line in the Events Table as a gray bar and it will show up on the Flow Rate graph as gray background shading. By looking at both the Flow Rate data and the Total Leak line, you can be begin to get a sense of where your PR machine draws the Large Leak line for your mask and your pressures. An example of how SH 0.9.6 flags one of my very patient's rare official Large Leaks is shown below. (This Large Leak has a number of really interesting characteristics, and I wrote a you can read about it in the blog post, [http://adventures-in-hosehead-land.blogspot.com/2013/09/anatomy-of-large-leak-in-encore-and.html Anatomy of a Large Leak in Encore and SleepyHead], analyzing which analyzes exactly what's going on in this leak. )<br />
[[File:large_leak_flage_zps357316c6.jpg]]
<br />
'''Part II: Are my leaks bad enough to worry about?'''
'''Interpreting the graphical leak data'''
The Leak Rate graph is the most reliable way of answering the question: ''Are my leaks both '''large enough''' and '''LONG enough''' to adversely affect the quality of my therapy and the accuracy of my data?''
'''Great, Good, and Decent Enough Leak/Total Leak lines'''
In general, a Great Total Leak line will be flat or almost flat and hover somewhere around (or just below) the intentional leak rate for your mask at your pressure. A Good Total Leak line will be "fuzzy" flat, stay mostly around the intentional leak rate for your mask and pressure, but tends to have some visible periods of noticeably higher leaks, most of which stay well below the cut off for "Large Leaks" for the given machine. A Decent Enough Total Leak line has more obvious leaks than a "Good" one does, but line stays below the Large Leak line for at least 70-90% of the night. (There's some debate between PAP users of just how long the Large Leaks need to last before they become problematic.)
For ResMed users or for folks who simply want to concentrate on the (excessive) Leak data, a Great Leak line will be flat or almost flat and hover somewhere around (or just below) 0.0 L/min. A Good Leak line will be "fuzzy" flat, stay mostly around 0.0 L/min, but tends to have some visible periods of noticeably higher leaks, most of which stay below 10-15 L/min. A Decent Enough Leak line has more obvious leaks than a "Good" one does, but the line stays below 25-30 L/min for at least 80-90% of the night. (There's some debate between PAP users of just how long the Large Leaks need to last before they become problematic.)
If we look at the Statistical Leak data from the Left Side bar for Great Leak/Total Leak lines and Good Leak/Total Leak lines, the 90% (or 95%) Leak/Total numbers will be under the manufacturer's definition of "Large Leak". The maximum may or may not be under that line.
'''Problematic Leak/Total Leak Lines'''
These are leak lines where it's clear that Large Leaks are present during a significant amount of the night, but it's not clear if the Large Leaks last long enough for the machine's manufacturer to say they are a problem.
The manufacturer with the clearest definition of when Large Leaks become long enough to adversely affect the quality of the PAP therapy and the accuracy of the data is ResMed: ResMed's infamous ''Mr. Red Frowny Face '' shows up on the machine's Sleep Quality Report when the (excess) Leaks are AT or ABOVE 24 L/min for at least 30% of the night. So we'll assume that if the time in Large Leak is approaching 30% of the entire night, the Large Leaks are problematic.
So a good working notion for a Problematic Leak/Total Leak line would be the following:
These are leak lines where it's clear that that Large Leaks are present during substantial amount of the night, and it's clear the Large Leaks are both '''long enough''' and '''large enough''' to adversely affect your PAP therapy.
A working definition of a Bad Leak/Total Leak line is that the leaks are bad enough to trigger a visit from ''Mr. Red Frowny Face '' if you were using a ResMed S9: If large leaks make up more than 30% of night, you've got a problem with leaks.
A Horrible Leak/Total Leak line is a leak line where the leaks are totally out of control: If over 50-60% of the night is in Large Leak territory, you've got a Horrible Leak/Total Leak line and a pretty significant problem with leaks.
'''A final comment on the connection between the Statistical Leak data and the graphical leak data'''
It is important to note that Decent Enough, Problematic, and Bad Leak/Total Leak lines may all have the same characteristics in the statistical Leak data:
'''The AHI Graph'''
This graph is often misunderstood by many new PAPers and because of that, we often recommend new SleepyHead users simply ignore this graph. And yet, many newbies are very interested in this graph. And so So in the interest of trying to clear up misconceptions about this graph, I've it is included it here.
The y-value in the AHI graph gives running count of the number of apneas scored during the last 60 minutes of the current PAP session. In other words, the y-value of the SH AHI graph at time t is the total number of events (OAs+CAs+Hs) recorded during the last hour of run time in the current session. When a particular event becomes one hour old, it is dropped from the running total. Because each event that is scored remains part of the AHI graph until it is an hour old, the AHI graph will remain above 0.0 for long periods of time when no events are being scored. The following image shows a series of 3 events scored within an 8-minute period, followed by over an hour of sleep with no additional OAs, Hs, or CAs scored. The AHI first increases to 3 and it stays at 3 until each of the three events "ages" out of the running total:<br />
[[File:ahi-graph-balanced_zpsa8d453f9.jpg]]
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'''AHI Graph and its connection to the Flow Rate graph and the Events table:'''
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A more complicated example.'''
When there is a lot of activity in flow rate data over a long period of time, what happens to the AHI graph may be more complicated. Here is a marked up copy of part of one of my a patient's AHI graphs that shows show what can happen when multiple clusters of events occur within 90 minutes of each other:<br />
[[File:AHI-graph-1_zps3721dd53.jpg]]
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At this level of zooming, SH does not label the events; and hence I've labelled each of the eventshave been manually labelled in this example, including flow limitations and the vibratory snore at the end of this window.
This particular hump in the AHI graph starts with OA1 at 5:26:21 with OA1, the first event recorded since I the patient turned my her BiPAP off and back on at 4:45. You'll notice that the AHI graph goes from 0 to 1 at this time.
When CA1 is recorded at 6:00:00, the AHI graph bumps up to 2. When OA2 is scored at 6:17:21, the AHI climbs to 3.
At 6:26:21 the AHI graph goes DOWN from 3 to 2. The reason is that OA1 is now an hour old, and hence it is no longer included in the list "events that occurred less than an hour ago."
At 6:28:14, the machine records OA3, and so the AHI graph goes from 2 back up to 3. The machine records H1 at 6:30:39, and the AHI graph goes from 3 to 4 at this point. The machine records H2 at 6:35:09, and the AHI graph increases from 4 to 5. I wake The patient wakes up shortly after H2 and I turn my turns her BiPAP OFF at 6:36:15. And itIt's my the turning the BiPAP off at 6:36:15 that causes the AHI graph to suddenly plummet from 5 to 0.
'''Note''': Any time the PAP machine is turned OFF and then back ON, the AHI graph is reset to 0 because a new session has started.
'''Note to only ResScan users:''' The AHI graph in ResScan resets to 0 at the top of every hour. Hence it is not going to look like the default SleepyHead AHI graph. If you want the SH AHI graph to look like ResScan's, you can use the "Zero Reset" option for the AHI/Hour graph in the SH Preferences. See [http://www.apneaboard.com/wiki/index.php?title=Beginner%27s_Guide_to_SleepyHead#Important_preferences_settings 7. Important preferences settings ] for finding the "Zero Reset" option.<br />
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