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PR Philips Respironics machines flag breathing that meets their definition of ''periodic breathing'' (PB). On the PR Philips Respironics web pages PB is defined as, "Periodic breathing is defined as alternating periods of hyperventilation with waxing/waning tidal volume..." Typically the waxing and waning pattern must be quite regular in visual appearance and it must present for at least a minute or two for PB to be scored. PB is flagged with a green back ground on the flow rate data. Often, but not always, there will be CAs (or Hs or sometimes OAs) scored at the nadir of the cycle. Sometimes the System One will only flag the most obvious part of the cycle:
PR Philips Respironics machines do not display this. Mathematically these numbers seem to be the Inspiratory Time in seconds divided by the Expiratory time in seconds, but perhaps this is actually being reported as a "percent" In other words, these numbers may actually be computed as:
spelling
If you are using a PR Philips Respironics machine, the most important part of the profile is to make sure you get the time zone correct on this first page. SleepyHead uses the time zone information to take the timestamps on the data and adjust it to local time if your machine uses GMT when recording the data. It's also important to remember to check the Daylight Savings time box if appropriate. If you make a mistake, you can edit the profile later. But it is easier to get the time right when you are creating the profile.
Once the profile is finished and saved, SleepyHead will display a blank page that looks like this:<br />
<br>
The format of the Statistics and Overview pages is straightforward. But it's worth looking at the pieces of the Daily Data window as part of the basic organization in SleepyHead. Here's a typical Daily data window for a PR Philips Respironics System One Auto:<br />
[[File:daily_parts_zpsee91cb1c.jpg]]
The amount of data available in SleepyHead can be overwhelming to new CPAP users, 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.
Most of the focus in this article is on how the daily data looks for ResMed and PR Philips Respironics machines. But most of it still applies to the data SleepyHead shows for any of the machines that it supports.
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.
NEW in SleepyHead 0.9.6: Large Leak Summary Data'''
For PR 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 PR Philips Respironics 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 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 Philips Respironics System One machines.
''
IMPORTANT NOTES about PR Philips Respironics System One machines:''<br />
'''1)''' The PR 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 VS1 scored)/(run time)
The thing is: VS1 snores are scored on a PR Philips Respironics machine only if the machine is running in Auto mode. If you are using a PR 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 PR Philips Respironics machine '''only if''' the machine is running in Auto mode.'' If you are using a PR 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.
'''
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 example patient uses a BiPAP and that's why there is both an IPAP and and EPAP line. The patient also uses a PR Philips Respironics machine, so that's why 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.
The EPAP line of the table looks like:
'''Statistical Leak Data'''
The most important data in statistical data is the Leak data. Because the patient uses a PR Philips Respironics System One, there are two lines of leak data and they look like this:
'''Leak Rate 0.00 0.00 10.00 14.00
* Since the maximum leak rate was 14 L/min, we know that for at most 10% of the night the patient's leaks were between 10 L/min and 14 L/min.
These Leak numbers are pretty good numbers for a PR Philips Respironics System One user.
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.
Interpreting the statistical leak data'''
If you use a PR 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]. PR 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 PR 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].
In general:
'''The Flow Rate graph'''
'''NOTE:''' ''ResMed S9, PR Philips Respironics System One, and F&P 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 PR 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 PR Philips Respironics central detection algorithm uses for testing the patency of the airway.
'''The Pressure graph'''
The Pressure graph shows the therapeutic pressure level throughout the night. Because this particular patient uses a PR 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.
If you are using your CPAP 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 CPAP 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.
'''The Leak Rate graph'''
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 PR Philips Respironics System One. A ResMed user is only going to see the purple Leaks graph.
In this example, the Redline option turned OFF because 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 is not the patient's best leak line, but it is a perfectly acceptable leak line for a PR Philips Respironics 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.
''
NOTE about Flow Limitation data:'' The PR Philips Respironics machines score FL in a very different way than the ResMeds do, and this means there is no FL graph for a PR Philips Respironics machine.
'''ALL OTHER GRAPHS'''
'''The Flow Rate graph---a detailed look'''
'''NOTE''': ''Only ResMed S9, PR Philips Respironics 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 SleepyHead''
The Flow Rate graph is a visual record of each and every breath you took while using the machine. You are inhaling when the Flow Rate is positive and you are exhaling when the Flow Rate is negative. Stronger inhalations result in higher (positive) peaks and stronger exhalations result in lower (more negative) valleys in the Flow Rate graph. The events from the Event Table are superimposed on the Flow Rate graph with vertical lines of different colors.
'''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 Philips Respironics System One APAP and BiPAP Auto also increase pressure in response to RERAs. The PR Philips Respironics 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-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]]
'''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, PRPhilips Respironics, 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'''
<br />
'''Tools to help identify Large Leaks: Large Leak shading for PR Philips Respironics System One machines'''
For users of PR Philips Respironics 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 Philips Respironics machine draws the Large Leak line for your mask and your pressures. An example of how SleepyHead 0.9.6 flags one patient's rare official Large Leaks is shown below. (This Large Leak has a number of really interesting characteristics, and 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], which analyzes exactly what's going on in this leak. )<br />
[[File:large_leak_flage_zps357316c6.jpg]]
* PR Philips Respironics System One users will see everything on this list.
* ResMed S9 users will see the AHI, Obstructive Apnea Index (OAI), the Hypopnea Index (HI), and Central Apnea Index (CAI).
* DeVilbiss IntelliPAP users will see the AHI, Apnea Index (AI), NonResponding Apnea Index (NRAI), and the Hypopnea Index (HI).
* Users of DeVilbiss IntelliPAP CPAP/APAPs, F&P Icon CPAP/APAPs, and PR Philips Respironics System One CPAP/APAPs will have Pressure data.
* Bi-level users will have IPAP/EPAP data regardless of the brand of machine.
* ResMed S9 CPAP/APAP users who use EPR will have IPAP/EPAP data because these machines act very similar to bi-levels. The IPAP data is the pressure level data; the EPAP data is the pressure level - EPR setting. In other words, if the pressure is 8 and EPR = 2, the IPAP = 8 and the EPAP = 6 = 8 - 2.
* ''The CPAP information'' on the left side of the panel is largely irrelevant at this point. SleepyHead defaults to a statistical model for approximating the (excess) leak for all machines other than the ResMed S9, which records only the excess leak. If you forget to change the Leak Calcs from "Mask Profile" to "Statistical Model" it really doesn't matter.
* ''CPAP clock drift'' should be left at 0 seconds unless you know your CPAP clock is off and you can't change the CPAP's internal clock. This patient's clock is off by a whopping 23 minutes, and because it's a PR Philips Respironics System One-- she can't change the CPAP's clock; hence the offset of 1380 seconds.
* ''Show Leak Redline.'' The default is to have this checked and the default value for the Redline is the ResMed value of 24 L/min. This is a NEW feature in SleepyHead 0.9.6. If you are using a ResMed S9, it's strongly recommended that you make sure Show Leak Redline is checked. If you are using a different machine, this may be a useful option for you, but you will need to change the value for the Redline. More on that later.
* ''Show compliance'' affects how low usage days show up in the Overview data and the compliance data in the Statistics page. The default line is 4 hours for obvious reasons. It's suggested that you leave this alone.
'''A detailed look at the Show Leak Redline option'''
The default is to have this checked and the default value for the Redline is the ResMed value of 24 L/min. This is a NEW feature in SleepyHead 0.9.6. Since our sample patient uses a PR Philips Respironics System One and she pretty much understands her leaks, she has unchecked the Redline so she doesn't get one in her daily leak graphs. If you want a line for helping you spot Large Leaks and you are NOT using a ResMed S9 machine, the first thing you will need to do is figure out whether your machine's manufacturer has an official definition of "Large Leak" or not. Here is some information on that:
<br />
* ''F & P Icon''. The F&P Icon reports TOTAL leaks and the F&P Icon definition for Large Leak is a TOTAL leak rate that is above 60 L/min. You should set the Redline at 60 L/min and you want to keep your TOTAL leaks under a Redline drawn at 60 L/min.
* ''Devilbiss IntelliPAP Auto''. The Devilbiss IntelliPAP reports Total leaks and the Devilbiss definition of Large Leak is a TOTAL leak rate that is above 95 L/min. You should set the Redline at 95 L/min and you want to keep your TOTAL leaks under a Redline drawn at 95 L/min.
* ''PR Philips Respironics System One''. The PR Philips Respironics machines report TOTAL leak, but PR Philips Respironics never tells us what the official definition of a Large Leak. SleepyHead 0.9.6 now flags the official Encore Large Leaks as gray bars over the Flow Rate graph. So if you get a lot of large leaks, you can use that data to help you decide where to draw a Large leak line. But until you get some data, here's a staring place to make some guesses about where to draw the Redline that are based on looking at a lot of Encore data from a lot of PR Philips Respironics users over the years:
** ''Older Series 50 System One machines''. If you are using a pressure setting that is higher than 8-10cm, Encore usually does not flag Large Leaks until the Total Leak rate is up around 90-100 L/min. If you are using very low pressures (4-8cm), Encore may start flagging large leaks at around 60 L/min. So start by selecting a Redline of 90 L/min if you are using pressures above 8 cm and a Redline of 60 L/min if you are using pressures below 8 cm. Adjust if you see Gray Large Leak bars in your actual data.
** ''New Series 60 System One machines''. If you are using a pressure setting that is higher than 8-10cm, the Encore software usually does not flag Large Leaks until the Total Leak rate is up around 80 L/min. If you are using very low pressures (4-8cm), Encore may start flagging large leaks at around 50 L/min. So start by selecting a Redline of 80 L/min if you are using pressures above 8 cm and a Redline of 50 L/min if you are using pressures below 8 cm. Adjust if you see Gray Large Leak bars in your actual data.
ResMed machines record and report only the ''Excessive Leak''. The S9 takes the raw (total) leak data and the mask setting and uses that to record the ''Excessive Leak'' data. The raw Total Leak Rate data is not recorded to the SD card or the machine's internal memory.
SleepyHead uses '''''Total Leak Rate''''' to refer to the leak data recorded by PRPhilips Respironics, F&P, and DeVilbiss machines; the SleepyHead Total Leak Rate includes both the intentional leak rate and the excessive leak rate. SleepyHead uses '''''Leak Rate''''' to refer to only the excessive leak rate. It's important to remember the following things about the SleepyHead Total Leak/Leak Rate data:<br />
* ResMed users will only have ONE leak line and it is Leak Rate.
* PRPhilips Respironics, F&P, and DeVilbiss users will have TWO leak lines: One for Total Leak Rate and one for Leak Rate.* The Leak Rate for PRPhilips Respironics, F&P, and DeVilbiss users is calculated by SleepyHead from the data recorded by the machine. SleepyHead uses a statistical analysis of the Total Leak Rate data to determine an estimate for excessive leak rate and reports that estimate as Leak Rate. If you are using a bi-level device or if you are using an APAP with a wide range of pressures, it is possible that the estimated excessive leak rate may not be accurate; in that case you are better off looking at the Total Leak Rate data and using it to determine how good or bad your leaks are.
<br />
* '''Philips-Respironics System One:''' There is no official "line in the sand" for flagging a Large Leak.
(Source: [http://www.healthcare.philips.com/pwc_hc/us_en/homehealth/sleep/encoreanywhere/pdf/1083140_EncoreReport_Guide.pdf Encore Report Guide])
Lots of System One user data posted on the forum indicates the Large Leak line for Total Leak Rate depends on whether the machine is a Series 50 (older) System One or a Series 60 (newer) System One. Lots of user data posted on the forum also indicates that the Large Leak line depends on the pressure used: People using less than 10 cm of pressure see Large Leaks being flagged much earlier than people using pressures greater than 10 cm. Here are some general estimated guidelines for where the undefined PR Philips Respironics Large Leak line is located:
:* ''Series 60 System One'' users may start to see Large Leaks being flagged when the Total Leak Rate reaches 60-70 L/min; if the prescribed pressure setting is below about 8cm, then Large Leaks may be flagged when the Total Leak Rate reaches 50-60 L/min in some circumstances.
<br />
Official Large Leaks for PR Philips Respironics System One machines are very difficult to determine with great accuracy in versions of SleepyHead prior to 0.9.6. In version 0.9.6, the Encore-defined Large Leaks are flagged by gray bars in the Events table and as a gray background in the Flow Rate curve. The Official Large Leaks for a System One will NOT be flagged directly on the SleepyHead Leak/Total Leak graph.
If you want to add a Redline to your Leak/Total Leak graphs in SleepyHead, our advice is to look at your own Large Leak flags and figure out where they seem to start. If you don't seem to have very many Official Large Leak, then use the above guidelines as a decent enough starting guess for where your particular Redline should be drawn.<br />
And notice all those Pressure Pulses (the little boxes) right before the gap in the wave form and right after the wave form pics back up? It's likely those PPs are being used by the BiPAP to try to figure out if there's a live, breathing person at the other end of the hose. Perhaps the BiPAP "realizes" that these periods of very low variation in the wave flow are way too long to be a typical apnea or hypopnea, and that's why they are not flagged as such. But it also gets so befuddled about what it's seeing in the wave form data, that the BiPAP concludes she must not be breathing through the mask and so it quits recording Flow Rate data form during the time it cannot determine any meaningful breathing pattern. When this patient showed her DME this wave form pattern (in a different context), the Respiratory Therapist referred to it as a "patient disconnect". (And yes, that tern is bothersome because "patient disconnect" seems to imply that ''the patient'' disconnected the machine from her nose, when she did not do that here or anywhere else). But for now on, we'll call those wave patterns "patient disconnects" even though we don't like that language at all.
A couple of minutes after the BiPAP detects the "patient disconnect", it finds rudimentary evidence of breathing again, so it starts recording the Flow Rate data. But by this point the leak rate has also grown to about 55 L/min and the BiPAP decides to flag this as an official Large Leak. As in-- there's breathing present and the leak is now large enough to meet that unknown PR Philips Respironics standard of Large Leak. And it's important to note that almost as soon as the Large Leak is detected, the patient's BiPAP starts to lower the pressures: First from 8/6 to 7/5 and then more sharply from 7/5 to 6/4. Her BiPAP is attempting to help limit or even fix that Large Leak by lowering the pressures---exactly as the description of the PR Philips Respironics Auto algorithm says it is supposed to do in the presence of Large Leaks.
As far as accuracy of recording events during this Large Leak: Because her BiPAP can barely detect a breathing pattern, it's clear that the usual definitions used to flag OAs, CAs, and Hs are going to be difficult to apply: They all rely on a reasonably accurate baseline of the current airflow into/out of the lungs and that baseline is calculated using several minutes worth of data. Because the breathing pattern is barely there, it's almost impossible for the machine to detect enough of a decrease in airflow to trigger flagging an OA or a CA or an H throughout the Large Leak (and even in the part of the longer, not-quite-so-large leaks immediately preceding and following the official Large Leak itself.) And hence there's no good reason to believe that this time frame is really as "event-free" as the event chart makes it appear to be: After all, you can't detect an apnea or hypopnea if you can't detect the breathing pattern in the first place.
But our CPAPs have no way to determine the effort to breathe. Hence CPAPs cannot distinguish between obstructive and central apneas in the same way that the technician monitoring a PSG does. Originally full efficacy data CPAPs did not try to distinguish between obstructive and central apneas. (The F&P Icon still does not try to distinguish types of apneas.) But when manufacturers started designing Auto CPAPs, a potential problem had to be addressed in the Auto algorithms: A minority of CPAP users are sensitive enough to pressure to develop problems with pressure-induced central apneas. And the tendency to have problems with pressure-induced centrals is more pronounced the higher the pressure setting on the CPAP. Hence early APAP Auto algorithms often were designed to NOT increase the pressure in response to apneas scored at pressures of 10cm or greater. In an effort to get around this difficulty, many of the current generation of full efficacy CPAPs make an effort to distinguish between apneas are presumed to be obstructive and those that are presumed to have a high probability of being central, and an APAP with such a "central apnea detection" algorithm can be programmed to respond to the apneas classified as obstructive and ignore the other apneas.
ResMed and PR Philips Respironics CPAP machines use (different) proprietary algorithms to test the patency of the airway and use the result to classify each apnea as a ''clear airway apnea (CA)'' or an ''obstructive apnea (OA)''. When the data from the algorithm leads to an ambiguous result, the apnea may be scored as an unknown apnea (A or UA). Both ResMed and PR Philips Respironics Auto machines will increase the pressure in response to clusters of OAs, but they will not increase the pressure in response to apneas scored as CAs.
DeVilbiss machines use a very different algorithm to classify each apnea as an ''apnea (A)'' or a ''non-responding apnea (M or NRA)''. A DeVilbiss Auto machine will increase the pressure in response to events classified as "apneas", but it will not increase the pressure in response to "non-responding" apneas.
As near as I can tell, F&P machines do not try to distinguish the type of apnea. And I have not been able to find any specific information about how the F&P Icon responds to machine scored apneas.
It's also important to remember that the ResMed and PR Philips Respironics algorithm for distinguishing between OAs and CAs and DeVilbiss algorithm for distinguishing between As and NRAs are not infallible. They are prone to misclassifying apneas under certain circumstances. For most users, it's not a huge problem, but for a small number of users, it can be an issue. We're not familiar enough with the DeVilbiss alogrithm to have a good sense of its limitations. But both the ResMed and PR Philips Respironics algorithms are based on using variations in the CPAP pressure to test the patency of the upper airway. As such they both have the same broad characteristics:<br />
* A CA scored by either the ResMed or PR Philips Respironics CA algorithm is very likely to be a "real" CA in the sense that the airway is clear (open). As such, a real OA is not very likely to be mis-scored as a CA on either a ResMed or PR Philips Respironics machine.* Scoring a real central apnea (as scored on an PSG) does not depend on the patency of the upper airway; hence there is a higher probability that a real CA may be mis-scored as an OA by the PR Philips Respironics and ResMed CA detection algorithms* Both the PR Philips Respironics and ResMed CA-detection algorithms are more likely to have problems detecting CAs at higher pressures. In other words, as the pressure increases, the chances that a CA is mis-scored as an OA increase
<br />
In addition to scoring apneas and hypopneas, many CPAP machines score ''snoring and/or flow limitations (FL)''. The way machines score this things varies quite a bit, and they are discussed at length in [http://www.apneaboard.com/wiki/index.php?title=Beginner%27s_Guide_to_SleepyHead#Snoring_Data 10. Snoring Data] and [http://www.apneaboard.com/wiki/index.php?title=Beginner%27s_Guide_to_SleepyHead#Flow_Limitations 11. Flow Limitations].
In addition to scoring OAs, CAs, Hs, snoring, and FLs, the '''PR Philips Respironics System One machines''' also score ''respiratory effort related arousals (RERAs)'' and '''periodic breathing''' (PB) in the events table with flags on the Flow Rate curve.
'''RERAs'''
There are people whose PSG indicates that they a normal diagnostic AHI (less than 5), but who experience enough RERAs for the RDI to be seriously elevated. Such people often wind up with a diagnosis of ''upper airway resistance syndrom (UARS)'' instead of OAS. The connections and differences between UARS and OAS are still being debated in the sleep medicine community. But the usual treatment for UARS is CPAP therapy since CPAP can be used to smooth out the breathing and prevent the RERAs from happening.
Since a RERA requires an EEG arousal to be scored and there is NOT a clear definition of how much the flow rate must be reduced for a RERA to be scored, most CPAP machines do not attempt to flag RERAs. But Philips Respironics has developed a proprietary algorithm for scoring what it believes are RERAs. Since there is no EEG data, the PR Philips Respironics RERA algorithm is based on a statistical analysis of what the wave flow for real RERAs on PSGs looks like: Loosely, the PR Philips Respironics RERA algorithm looks for evidence of increasing respiratory effort (i.e. "flow limited breathing") followed by one or more "recovery" breaths. When we look at the RERAs scored in our sample patient's data, it's sometimes difficult or impossible to see both the "evidence for increasing respiratory effort" and the "recovery breaths". We've also noticed that the placement of the RERA tick mark is far less consistent: Sometimes it appears at the ''beginning'' of the RERA, sometimes it appears at the ''end'', and sometimes it appears in the ''middle''. But every now and then we see a RERA where it is easy to see why it was scored:
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[[File:RERA_zpsb08c57f0.png]]
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Because the RERA algorithm is proprietary and is based on just flow rate data rather than (flow rate + belts + EEG), it's important to understand that RERA flagging by the PR Philips Respironics machines should be considered an "extra" that is probably not always accurate. The RERA algorithm probably flags things that aren't real RERAs and it probably misses some real RERAs as well.
Nonetheless, if your sleep study showed a large number of RERAs the PR Philips Respironics RERA scoring algorithm may be useful for partially monitoring how well the CPAP is doing in terms of preventing RERAs from occurring.
'''Periodic Breathing'''
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[[File:PB_zpsee6cff1e.png]]
* '''ResMed S9:''' The numbers in parenthesis are the length of the event measured in seconds.
* '''PR Philips Respironics System One:''' The numbers are event markers. For CAs, OAs, Hs, PBs, and LLs, the numbers are usually a good approximation of the event length measured in seconds. For RERAs, it appears that the number is a good approximation of the event measured in seconds. For VS, VS2, and FL it is not at all clear what the meaning of the numbers is. SleepyHead uses the VS2 numbers to draw the Snore graph; presumably the higher the number attached to a VS2, the louder OR longer the snoring. It's not clear which. For more information on how the PR Philips Respironics scores snoring see [http://www.apneaboard.com/wiki/index.php?title=Beginner%27s_Guide_to_SleepyHead#Snoring_Data 10. Snoring Data].
* '''DeVilbiss IntelliPAP:''' The numbers in the parenthesis are usually single digit numbers and it is not clear what their meaning is. Since the IntelliPAP does not record Flow Rate data, it is impossible to see whether there is some connection between these numbers and the lengths of the events.
* '''F&P Icon:''' The numbers in parenthesis seem to always be 1, and hence they are not related to the length of the event. You can zoom in on each event in the Flow Rate curve and estimate the length of the event visually.
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This particular hypopnea's flag is more or less in the middle of the hypopnea. Most of the time the flag is closer to the end of the event, but there is some variability. Another thing that's worth pointing out is that the patient's BiPAP is in the middle of decreasing the IPAP as part of the PR Philips Respironics "search" algorithm; the isolated H does not cause the machine to increase the IPAP and that's a bit counter intuitive to some CPAP users. But it is how the PR Philips Respironics Auto algorithm works: It ignores isolated Hs and OAs; pressure is increased for events only if two or more events occur very close to each other.
'''Clusters of events'''
So the overall goal in every manufacturer's Auto-algorithm is to increase the pressure just enough to prevent more events from happening in next few minutes and allow the breathing to stabilize. The idea is to avoid jacking up the pressure unnecessarily: That can lead to more unstable breathing, discomfort, and more pressure than is needed to keep the airway open most of the time. And once the machine is satisfied the breathing is indeed stable, the Auto-algorithm will decrease the pressure until there is evidence that the airway is once again in some danger of collapsing.
Each manufacturer's Auto-algorithm handles the details of how to handle the pressure increases and decreases in its own proprietary way. Some machines are more aggressive and increase pressure faster in response to snoring, flow limitations, and events. Some take small 1cm steps in increasing the pressure and then wait for a minute or more before increasing the pressure further. The PR Philips Respironics machines even have a search algorithm that periodically tests what happens to the Flow Rate curve when a modest pressure increase is applied even when there are no scoreable events (OAs, Hs, FLs, RERAs, and Snoring). And likewise, each manufacturer's algorithm has a different way of deciding when to start decreasing the pressure and how fast to decrease the pressure.
It's clear from reading informational material aimed at clinicians, that each manufacturer believes that they have the "best" algorithm. But what little information that has been published about independent bench trials seems to indicate that while real differences in the auto-algorithms can be quantified, the clinical significance of those differences is much harder to evaluate. This may be one reason that some sleep docs are so reluctant to prescribe APAP therapy as the first course of treatment for ordinary OSA.
= Snoring Data =
ResMed S9s, PR Philips Respironics System One CPAP and DeVilbiss IntelliPAP machines record snoring data. F&P Icons do not record snoring data.
'''How does a CPAP machine detect snoring?'''
'''Snoring data on a PR Philips Respironics System One'''
'''Please note the following:''' The way snores are recorded on the ResMed S9 machines is very different than the way it is recorded on the PR Philips Respironics System One machines. This information applies only to the snore data recorded by the PR Philips Respironics System One machines and how that data is reported in both the SleepyHead and Encore software packages.
'''''All about Snoring Data on the PR Philips Respironics System One Machines'''''
There's no official guide to how to interpret the Snoring information from the PR Philips Respironics System One as it is reported in either SleepyHead or Encore. In looking at Encore numbers, the assumption is that the higher the so-called "VSI" number is, the more serious the snoring is. But exactly how large that number needs to be before it's troublesome is not known. And for reporting snoring in SleepyHead, JediMark had to reverse-engineer the snoring data from the PR Philips Respironics machines and the information on why Encore presents the snoring data the way it chooses to present it is pretty scarce...
And when you start analyzing the ''raw snoring data'' the decisions Encore makes on how to ''present'' the snoring data seems bizarre from a statistical point of view. (More on that later.)
Once JediMark started reverse-engineering the snoring data, he discovered that the PR Philips Respironics machines were keeping track of two kinds of snoring data; JediMark has chosen to call these two types of snore data ''Vibratory Snores (VS)'' and ''Vibratory Snores #2 (VS2)''. Those of us who had access to Encore Pro and had data from both straight pressure mode and auto mode were able to help JediMark figure out just what the significance of those two kinds of snores are in the Encore/PR world are. Here's the run down as we now understand things:<br />
'''''VS snores'''''
VS snores are recorded ONLY when a PR Philips Respironics machine is running in Auto mode. If the machine is set to straight CPAP (or straight BiPAP), the machine will NOT record VS snores. If the machine is a model number 450/460 (System One PRO) or 650/660 (System One BiPAP PRO), the machine will NOT record VS snores.
The VS snores have ''time stamps'' attached to them, but they do not have a "magnitude" number. In the SleepyHead "events" list, when you look at the detailed information for each VS snore event, the number in parenthesis will always be a 0. ''But VS snores are the snores that cause the Auto algorithm to respond by increasing the pressure.'' (On a BiPAP Auto, it's the EPAP that is increased.) For each VS scored, the machine typically increases the pressure by 1 cm. Hence if there's a cluster of VS's, the machine will keep increasing the pressure until either the snoring stops or the max pressure setting is reached. It's also worth noting that in all the data we've seen, in dense clusters of VS snores, the VS snores appear to be scored in roughly one minute intervals---in other words, there is usually a full minute between adjacent VS snores.
In Encore, the VS's do NOT seem to show up as tick marks in the Events table. But it's hard to say for sure. Where they do show up is on the wave form when you look at it in Encore Pro (or EncoreBasic). Of course, Encore only downloads the wave form for the last night (or sometimes the last two nights) when you down load the data. Encore Pro at least stores all the previously downloaded wave forms in the patient's database, but EncoreBasic only stores the last wave form. SleepyHead also puts tick marks for VS snores on the wave form data when a PR Philips Respironics machine is running in Auto and the VS data is being recorded.
So as far as we can tell: The VS snores make up the part of the snoring data that is used by the Auto-algorithm when it determines that the snoring is significant enough to warrant an pressure increase. But no one (except the PR Philips Respironics engineers) know what the scoring criteria for a VS snore actually is.
'''''VS2 snores'''''
VS2 snores are recorded by all PR Philips Respironics machines. They have both a time stamp and a "magnitude" number attached to them. In the SleepyHead list, when you look at the detailed information for each VS snore event, there will be a NON-zero number in the in parenthesis for that event. Whether that number represents ''the length the snoring went on or some kind of measure of the loudness of the snoring'' is anybody's guess. We really do not know the significance of that number.
JediMark's SleepyHead VS2 graph uses the "magnitude" numbers for the vertical-coordinates in the Snore graph. In other words, JediMark has set the SleepyHead VS2 graph up with the assumption that the "magnitude" numbers are somehow related to how bad the snoring is. That's not a totally unreasonable assumption since you can have VS2 events closely space together with some rather large "magnitude" numbers. But it is an assumption and there's no real way to verify whether this assumption is valid. That's why the units on the Snore graphs are labelled as "Unknown" when you hover the mouse over the vertical scale of the Snore graph.
The VS2 snores show up in Encore (all versions) as tick marks in the Events table based on the time stamp of the VS2 event. But the calculation of the VSI index in Encore is not as straightforward as you would expect.
No one outside of PR Philips Respironics really knows the difference between the changes in flow rate that are needed to score a VS and the changes needed to score a VS2. But some of the PR Philips Respironics System One machines can be pretty sensitive to picking up vibrations that are coming from sources other than the patient's own airflow. But that said, real snoring is picked up by the PR Philips Respironics System One as well as false snoring. You basically have to look at patterns in your own data and learn to interpret based on what you know is going on at night and what you think might be going on at night.
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'''Note:''' The VS events are not used to compute this index. This is important because:
: If you are using a PR Philips Respironics System One AUTO or BiPAP AUTO in FIXED pressure mode, your SleepyHead VSnore index will NOT include the VS snores in the Snore index.
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'''Important Note for users of earlier versions of SleepyHead'''
''
In pre-0.9.5 versions of SleepyHead, the SleepyHead VSI index used '''VS snores''' to compute the VSI.'' If you are using a PR Philips Respironics machine in '''''fixed pressure''''' mode and SleepyHead 0.9.3 (or earlier), SleepyHead will report a VSI = 0.0 even if you are snoring your head off!
'''Snoring Data in Encore, (the official software for PR Philips Respironics machines)'''
Encore calculates the VSI shown on the right sidebar of the Encore Daily Detailed data in a really bizarre way. We can illustrate this with data from our sample patient's data. On July 31, 2013, she had 3 VS 2 snores scored for the entire night. In SleepyHead, the data looks like this:
'''NOTE:''' DeVilbiss machines do NOT record FL data; F&P Icons do record FL data
What a FL is and how they're scored differently on ResMed and PRPhilips Respironics.
Main picture:
'''Inspiratory:Expiratory (ratio)'''
: [(Inspiratory Time in seconds)/(expiratory Time in seconds)] * 100%
'''Equipment description'''
Make sure your equipment profile is up to date and correct. Be precise in describing your CPAP equipment. There are six commonly used ResMed S9s and at least that many commonly used PR Philips Respironics System Ones; we need to exactly which model you are using. If you are including leak data, it helps to remind folks if you are using a FFM or not: It's irksome to be repeatedly told that you really need to switch to a FFM because of mouth breathing if you already use a FFM because you already know you're a mouth breather.
'''Getting feedback on the question: How am I doing?'''
A: All modern CPAPs store the '''compliance''' data on-board and they will write that data to the SD card when the SD card is reinserted into the CPAP. Some CPAPs store a fair amount of other data on-board as well as the compliance data, and all of the on-board data will be written to the SD card. How much data you will see for the night in SleepyHead depends on both the brand of CPAP you use and the version of SleepyHead you use.
* ''PR Philips Respironics System One'' users will lose the Flow Rate data and the "fancy stuff" computed from the Flow Rate data. But the Event Table, Pressure graph, and Leak graph should all show up in the Daily Graphs along with the daily summary data in SleepyHead 0.9.3.
* ''ResMed S9'' users will lose all of the detailed daily data and all of the Daily Data graphs. But summary data for the day should show up in SleepyHead 0.9.6.
* ''F&P Icon'' users need to import the data on a weekly basis; the F&P Icon overwrites the daily detailed data on a seven day cycle: In other words, tonight's detailed daily data replaces the high resolution data from one week ago.
* ''PR Philips Respironics System One'' and ''DeVilbiss IntelliPAP'' users can download much less frequently. These machines store several months to a year's worth of full efficacy data on the SD card. It's still not a bad idea to import the data into SleepyHead on regular basis in case the SD card becomes corrupted.
== Q: I've downloaded my data from a ResMed S9 Elite, AutoSet, VPAP S, or VPAP Auto, and there is no detailed data and SleepyHead says I didn't use the machine. What did SleepyHead do with my data? ==
== Q: I don't see any Flow Rate data. What am I doing wrong? ==
A: DeVilbiss IntelliPAP users will not see any Flow Rate data because the IntelliPAP does not record that data to the card. ResMed S9, PR Philips Respironics System One, and F&P Icon users will only see Flow Rate data if the card was in the machine while it was running; the Flow Rate data is written directly to the card. ResMed S9 and Icon users who do not down load their data at least once a week will only get the last 7 days of Flow Rate data for each down load: The S9 and the Icon both overwrite the Flow Rate data once a week.
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