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→Basic data interpretation: Daily Detailed Data
This article is primarily restricted to the most basic, important data for a newbie to concern themselves with. The focus is mainly upon the graphical data in the Daily Data window.
[[File:LeftSideBar_zps5909a752.jpg]]
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The single most important piece of numerical data is the AHI data, however everything in the left side bar can provide clues on the effectiveness of your therapy. The goal of CPAP therapy is to keep improve the continuity and quality of your sleep by keeping the AHI down below 5 night after night.
If your AHI looks good and your leak data is acceptable, then the CPAP 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
:'''Obstructive Apnea 0.39'''
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 Philips Respironics 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 Philips Respironics System One users to figure out whether their leaks are are significant enough to adversely affect therapy.
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 the patient had far more FLs than any other kind of scoreable scorable event. The information on the Pie Chart is the same as the information on the Event Bar Charts. We suggest turning off the pie chart because it uses a lot of vertical space that could be used for other statistical information (see [[SleepyHead Chart Organization]].
'''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 currently scored by Philips Respironics System One Dreamstaton CPAP and BiPAP machines, and Resmed Airsense 10 Elite or Autosets.
'''1)''' The Philips Respironics System One machines record two kinds of Snore Data. In SleepyHead they are referred to as VS1 and VS2 data.
:Vibratory Snore (index) = (number of VS2 scored)/(run time)
Vibratory Snore (index) = (number of VS1 scored)/(run time)
The thing is: VS1 snores are scored on a Philips Respironics machine only if the machine is running in Auto mode. If you are using a Philips Respironics 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 Philips Respironics machine '''only if''' the machine is running in Auto mode.'' If you are using a Philips Respironics 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.
This is located directly below the Pie Chart. Let's look at it more closely:<br />
means that the patient's minimum IPAP = 6, their median IPAP = 6, their 90% EPAP = 8, and their max IPAP = 8. That means that their IPAP stayed at 6cm for at least 50% of the night and the IPAP was LESS THAN or EQUAL to 8 cm for 90% of the night. From this data, we can't tell if the IPAP = 8 for almost 50% of the night or if the IPAP = 8 for only about 10-15% of the night.
The most important data in statistical data is the Leak data. Because the patient uses a Philips Respironics System One, there are two lines of leak data and they look like this:
The Total Leak numbers confirm that the patient's leaks are pretty well under control: The minimum total leak rate was 11.00 L/min; the median total leak rate was 14.00 L/min; the 90% total leak was 23.00 L/min; and the maximum total leak rate was 34.00 L/min. At the pressures used by the patient, the expected leak rate for their mask is about 20-29 L/min. So these numbers look very good: For 90% of the night the patient's total leak rate was AT or BELOW 23 L/min, which is right around the expected leak rate for their mask.
'''NEW in SleepyHead 0.9.6: Time over leak redline'''
For ResMed S9 users, SleepyHead 0.9.6 will report the percentage of time when the Leaks are over the ResMed RedLine at 24 L/min at the end of the Statistical data under the Pie Chart. This should make it easier for ResMed S9 users to figure out whether their leaks are are significant enough to adversely affect therapy. Users of other CPAP machines will not have this line in their Daily Data report.
'''Part I: Are my leaks bad enough to worry about?
Interpreting the statistical leak data'''
If you use a Philips Respironics 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 is: 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 CPAP 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 CPAP 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]. Philips Respironics 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 Philips Respironics data. That information is also talked about [http://www.apneaboard.com/wiki/index.php?title=Beginner%27s_Guide_to_SleepyHead#Leaks 8. Leaks].
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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.
This screen shot shows the four most important Daily Detailed graphs that are needed to have a clear understanding of your data and what's going on each night.
The Events Table is a snap shot that lets you see when all the events occurred and what kind of events they were. By default, the Events table is pinned to the top of the Daily Detailed Data graphs and will not scroll out of site. When zooming in on the other graphs, the Events Table will remain as is, with the zoomed in part of the night highlighted on the events table. So it also provides a useful reference tool for being able to quickly put the zoomed in graphs into the context of the whole night.
'''NOTE:''' ''ResMed S9, Philips Respironics System One, and Fisher & Paykel Icon machines record Flow Rate data if the card is in the CPAP machine during the night; the DeVilbiss IntelliPAP does NOT record Flow Rate data.''
The Flow Rate graph is also referred to as the "wave flow" graph. It provides a record of each and every breath you took all night long. At this scale, everything is all run together; the real power in the Flow Rate graph is when you zoom in sufficiently close to start seeing individual breaths and events. Note that each of the events in the event table shows up as a tick mark on the Flow Rate graph (with the exception of the Philips Respironics System One VS2 tick marks.) The little boxes appearing on the sample patient's Flow Rate graph are mostly Pressure Pulses that the Philips Respironics central detection algorithm uses for testing the patency of the airway.
The Pressure graph shows the therapeutic pressure level throughout the night. Because this particular patient uses a Philips Respironics 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.
This graph shows both the Total Leaks (light gold color on top) and the SleepyHead calculated (unintentional) Leaks (purple on bottom) because I'm using a Philips Respironics System One. A ResMed user is only going to see the purple Leaks graph.
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.
===The Flow Limitation 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. Flow limitation is an important component of pressure increases in auto CPAP and BiPAP machines.
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NOTE about Flow Limitation data:'' The Philips Respironics machines score FL in a very different way than the ResMeds do, and this means there is no FL graph for a Philips Respironics machine.
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 later.
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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 />
'''NOTE''': ''Only ResMed S9, Philips Respironics System One, and Fisher & Paykel 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 SleepyHead''
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.)
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.)
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 concerning the Pressure graph.
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 doctor about any changes to your therapeutic settings.<br />
Depending on what machine you are using, the Leak Rate Graph will have either one or two graphs in it.
The top (gold) graph is the Total Leak Rate graph and the bottom (purple) graph is the ''Leak Rate graph'', which shows the SleepyHead estimated excess leak rate.
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, Philips Respironics, Fisher & Paykel 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].
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'''Interpreting the graphical leak data'''
Loosely, Leak and Total Leak lines can be described as "Great", "Good", "Decent Enough", "Problematic", "Bad", and "Horrible", all of which are based on the amount of time the leaks or total leaks are in Large Leak territory for your particular machine.
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 CPAP users of just how long the Large Leaks need to last before they become problematic.)
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.
If you see a Problematic Leak/Total Leak line every now and then, there's no point in worrying about it. If you see Problematic Leak/Total Leak lines a lot, however, you may want to consider taking measures to address the leak issues.
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 CPAP therapy.
This graph is often misunderstood by many new CPAP users and because of that, we often recommend new SleepyHead users simply ignore this graph.
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