Chart Interpretation and a Few Other Questions

[questor1]

Since changing medication (Ambien to Clonazepam) and mask size, my leaks are fewer and less severe, as are the number of events and my AHI. All in all, I'm pleased with the results, but do have a few questions. Now that the events are not spread over the entire night, I'm seeing that the vast majority take place between 3 and 4 AM. Events during this time frame have been consistent since day one. Another observation is that I never have any events during the first 90 minutes. Below is a 30 minute slice from last night, there were no events prior to or after this section and all the graphs were about what you see to the left of the first event. (The red marks were made by me) Here are a few question and thoughts. I would appreciate feedback from our gurus.

1) What is the difference between Flow and Flow Limitation? Isn't one just the opposite of the other?
2) What is the significance of the numbers at the top of each event marker? Is it the duration of the event in seconds?
3) Are markers placed at the beginning middle or end of the event?
4) What are the two blue squares I have circled?
5) Does anyone see anything unusual or interesting in the graph?
6) Is there anything I can do to improve things? At first I thought about raising the pressure, but I suspect that will increase leaks and not do the trick. Then I thought about the ramp up time. I currently have a 30 minute ramp up. Since I never have events during the first 90 minutes, I thought lengthening the ramp up time might at least push the events further into the night, thus giving me a bit more uninterrupted sleep.

[zoocrewphoto]

1) What is the difference between Flow and Flow Limitation? Isn't one just the opposite of the other?

Flow limitation is simplified in the graph. They show open, partially blocked, and blocked. The flow graph is actually showing your breathing. If you zoom in, it gets more detailed.

2) What is the significance of the numbers at the top of each event marker? Is it the duration of the event in seconds?

Yes, it is the duration.

3) Are markers placed at the beginning middle or end of the event?

Not sure. I would need to zoom in on the graph and see. I know that it doesn't register an event until 10 seconds has elapsed, but I'm not sure how it places it on the graph. If you zoom in and have it show the breathing graph next to the event graph, you can see how it correlates.

4) What are the two blue squares I have circled?

I didn't see any blue squares.

5) Does anyone see anything unusual or interesting in the graph?

You have some longer events. Mine rarely go over 17 seconds. I would be concerned about apneas that last 30 seconds or more. A few longer events are harder on your body than more shorter events.

6) Is there anything I can do to improve things? At first I thought about raising the pressure, but I suspect that will increase leaks and not do the trick. Then I thought about the ramp up time. I currently have a 30 minute ramp up. Since I never have events during the first 90 minutes, I thought lengthening the ramp up time might at least push the events further into the night, thus giving me a bit more uninterrupted sleep.

You need to include the graph for pressure and resize it so that the whole image shows up on the page. The chart appears to go off screen. You may need to adjust the pressure a little to eliminate those longer events. You might also include a full night graph along with the short time span there, so that we can see how the full night is going.

[Jay Aitchsee]

Questor, it good to see you're doing pretty well. While we're waiting for you to post more charts and the S9 experts to chime in, I'd just like to say that many of us have found that reducing or eliminating the comfort features such as RAMP and EPR have actually improved out therapy. I doubt that extending your ramp time would have much impact on your late night events. It's possible the events you are exeriencing routinely between 3 and 4 AM are position related. You could set your laptop up, do a timelapse video, and see what's happening around that time.

Jay

[zoocrewphoto]

I forgot to mention that extending the ramp time means that you will go longer with the machine not able to respond to signals that you may be about to have an apnea. In other words, you could go untreated with a sub therapy pressure. I don't know if the machine is programmed to record events during the ramp as it isn't program to treat events during ramp. So, they may be occurring and you just don't know. I only used ramp for 2 days, so I have no data to look at to see if it showed any events.

[avi123]

[quote="questor1"]Since changing medication (Ambien to Clonazepam) and mask size, my leaks are fewer and less severe, as are the number of events and my AHI. All in all, I'm pleased with the results, but do have a few questions. Now that the events are not spread over the entire night, I'm seeing that the vast majority take place between 3 and 4 AM. Events during this time frame have been consistent since day one. Another observation is that I never have any events during the first 90 minutes. Below is a 30 minute slice from last night, there were no events prior to or after this section and all the graphs were about what you see to the left of the first event. (The red marks were made by me) Here are a few question and thoughts. I would appreciate feedback from our gurus.

1) What is the difference between Flow and Flow Limitation? Isn't one just the opposite of the other?

No, Flow Limitation is the constriction of respiration Flow in the upper airway (mostly in the nose) which does not qualify to be an Event (Obstructive, Central, or Hypopnea). Resmed Machines diagnose these by the level of flattening of the respiration WAVES from roundness shapes of the tops to flat.

In Resmed machines it includes UARS an RERAs (Google), and it is often manifested as Snoring.

As you raise the pressure in the S9 Autoset from 5 cm up then the first duty of the machine is to treat Flow Limitation and Snoring. Obstructive apneas are usually treated at pressures above 10 cm. Central apneas are not treated by raising pressure.



2) What is the significance of the numbers at the top of each event marker? Is it the duration of the event in seconds?

Already answered above.

3) Are markers placed at the beginning middle or end of the event?

Markers (Flags) are placed at the end of the Events. If you slowed down the time in your graphs to 5 or 0ne minute you would then have seen it.
But sometimes there is a "Skew" created in the SD Card which places the flags off place.


4) What are the two blue squares I have circled?

Small solid black squares are Hypopneas

5) Does anyone see anything unusual or interesting in the graph?

Yes, your sleep time is too short.

6) Is there anything I can do to improve things?

Just continue. But you need to show complete data lasting the whole night.

See below how I set my own pressure on the S9 Autoset (while in the APAP mode) and also the needed data
to cover while checking my treatment:




If you're using a Resmed machine and want to discuss your treatment then please try to post these kinds of ResScan data:


One night Stats report:



If you have, 30 days Stats report:




If you have, 6 months Stats report:



Pressure and Events graphs:

(Data for APAP= AutoCPAP mode is shown)



This set-up took me some time to arrive at by following the pressure graph in Rescan. I strated with the first set- up by using the optimal CPAP pressure from my latest sleep study. But later, I fine tuned the setup, by changing the limit pressures gradually as to have the pressure graph only "kiss" the two limit lines of max and min pressures. See the graph above. The idea was to set the limits so that the machine should not 1) Waste time responding to events, and 2) Run the pressure up, suddenly, and cause new Emergent Central Apneas and also cause the ingested air to rise.

Leak and Snore graphs:



Flow and Flow Limitation graphs:

(the Flow graph will be needed to show detailed graphs in the double panels)




Example of location of Flags and checking the shape of my respiration waves:





Example of Skewed data on the S9:

[archangle]

Flow limitation is based on the shape of your flow graph. With "flow limitation", your airflow has a flat top instead of a round shape. This indicates that your airway is restricted. Think of it as being like having your nose stopped up to the point where air is just barely getting through.

You could find flow limitations by looking closely by looking at the flow waveform, but the separate graph makes it stand out better.

"Normal" apnea and CPAP is worried about when you stop breathing or greatly reduce it for a short period of time, after which you will wake up a bit and open your airway. Flow limitations can be an all night long type of thing and may need to be treated a little differently from apneas.

[questor1]

Thanks again for all the replies and great information. The reason I only included the 30 minute section was because everything was smooth on either side of those events. Last night my AHI was down to 1.6. If I post again, I'll post full charts and reports. I spend at least 8 hours in bed, but often only wear the mask for 4-5 hours. As some point, I wake up and can't get back to sleep (or don't/won't spend enough time get back to sleep). At that point I remove the mask and almost immediately go to sleep for the rest of the night. Of course I have no tracking of events during that time. For now, I'm going to work on going back to sleep with the mask on.

[patrissimo]

I will be getting my first graph like this tonight, so I have no experience in evaluating these graphs, but I have a question for those who do: Isn't quester1's flow graph very irregular and periodic? That is, rather than showing consistent breathing throughout the night, starting at about 2am there are numerous sequences that look like a triangle pointed right, that is where the breath amplitude gets smaller and smaller over what looks to be about 5-20 minutes. For example, 3:25am, 4am, 4:20am. In fact, the whole flow graph after 1:50am looks totally different than the first hour, which looks more like what I'd expect for normal breathing.

These flow magnitude reductions are usually (but not always) accompanied by spikes in the FL graph, and seem to always end in apneas or hypnopneas. If these are obstructive events, why is the machine not ramping up pressure as the breath magnitude shrinks to compensate? If these are central events, wouldn't this graph suggest the need for an ASV?

Again, I have no experience looking at these types of graphs, so I'm putting my interpretation out for correction by those who know more.

[questor1]

Patrissimo, like you I am new, but I can provide a fact and some speculation. My CPAP is not set for automatic adjustment, which is why there is not ramp up of pressure in response to an event. It provides a constant pressure at a setting of 11. I would speculate that some of the irregularities you see in the flow are a result of the constant pressure combined with leaks that you see taking place. I would also speculate that during that time of the night, I move around a lot more than at other times. I have a trail camera that I think I'll set up tonight to confirm my speculation.

[patrissimo]

Oh, I see, so you have an AutoSet but it's set to straight CPAP mode?

You might want to try it on AutoSet 10-18 or something like that (depending what you can tolerate at the high end) for a few nights to see how high the machine drives pressure to stop your events and if it works. Then either pick a new AutoSet range, or if you go back to straight CPAP, you can pick a better pressure setting based on the experiment. If those are obstructive events, it sure seems like your pressure is too low.

If you have a straight CPAP machine, I'd try a self-titration where you bump up the pressure a little each night, as long as you are tolerating it, and then graph pressure vs. AHI for that time period. I dunno if this is standard practice, but it seems like the right thing to do if you don't have an APAP or ASV.

[questor1]

At this point, I'm just going with what my Dr. and I discussed. Right now things are going in the right directions. Considering I had more than 300 events during the sleep study and just 3 last night, I think I'll just stay the course. I suspect the more I get used to it, the better it will get.

[questor1]

Well I set up my trail camera to catch the wildlife in my bed. I took one picture every minute and this is what I found. I only had three events during the night. All three took place within a 3 minute period that corresponded with 2 major leaks (25+). It was roughly a 1 min leak, followed by 1 minute of normal flow, followed by a 1 minute leak, followed buy normal flow. When I compared the chart with the photos of that same time period, I had turned from my left side to my back. As I continued to compare the chart to the photos, it was obvious that other less significant leaks were also associated with shits in position.

With only 3 events, an AHI of 0.6, and seeing that the events correspond with movement and leaks, I'm confident that I'm on the right track. On the down side, I'm still only averaging about 5 hours before I remove the mask. It may be a question of adjusting to the CPAP or it may be my 4 legged alarm clock (cat). I'm going to continue the photo studies and see if she has anything to do with it. It's possible that she is rousing me.

I'm not a cat person, but I am convinced that they are smarter than most people think. She has a routine when she wants food in the morning. She will sit on the window sill and rattle that blinds for a while. If I ignore her and don't get up, she walks across the foot of the bed. If that doesn't do it, she makes a second pass across my chest. If that doesn't get me up, it's face to face time. I'm wondering if she is doing things that rouse me before I'm aware of her presence. A different camera angle will tell me that tonight.

[Jay Aitchsee]

Good job!