OSCAR analyzing software

can't post chart

My first thought is that this is not a OSCAR or SleepyHead issue. All the software does is display the data that the CPAP/BiPAP machine has captured. It is the machine that determines the types of events. Yes, the machine can make mistakes, and the event classifications should not be considered as absolutely correct. However, they are a good indication of what is going on. If you want to zoom in on events to expand the scale and look at them in detail you can form your own opinion as to how accurate the classification is. I suffer from CA events, and then hypopnea events next. OA events are almost always low. Hypopnea is generally assumed to be a flow reduction due to restriction of air flow, or obstructive in nature. However, they can actually be due to reduced effort to breathe which is a central effect. My suspicion is that most of my hypopnea events are central in nature rather than obstructive. Here is an example from last night to look at zoomed in. You will see there is a series of events; RE, CA, CA, CA, H. If you look at the minute ventilation you can see that the flow was cycling prior to these events, and really started about 2:33.45. Something disturbed flow. Perhaps the mask moved or something. This was really the starting point of the event series and it is due to my issues with breathing control that cause central apnea. For whatever reason my breathing control system is not stable. If something upsets it, it starts to cycle as can be seen most easily with the minute ventilation. At the RE I may have even woken up. But you can see the cycle continues. The final event is classed as a hypopnea, but I would say almost for certain it is just a CA event that did not go to full loss of air flow. This is an example of why I more or less lump in my hypopnea events with the CA events as part of the same problem. Where the rubber hits the road is when you are trying to decide what to do about it. If the hypopnea events are obstructive in nature one would benefit from more pressure. If they are central, then more pressure may make it worse. For this night my total AHI was 3.31, with 1.66 CA, 0.25 OA, and 1.40 H. My conclusion is that if anything the pressure may be too high, not too low. This is an example of how I use SleepyHead.

If you are wondering about whether an event is a CA or OA, you can second guess that too by looking at it up close. The ResMed tries to cycle flow to see what it does to pressure. If the airway is closed the pressure will fluctuate with a higher amplitude. If the airway is open the pressure fluctuation is lower. Here is an example of two events side by side. Here is an example of the two events side by side. Notice how the mask pressure fluctuates up and down and paints a band of pressure fluctuation in response to the machine testing for obstruction. In the OA event the band or pressure fluctuation is wider than for the event that gets classed as a CA. The difference is not huge, but it is there. Does the machine sometimes make a mistake in classification? Probably at times. By my eye the machine it right in this example. And again like the previous example that H that follows the CA event is probably central in nature.

Is this potential minor inaccuracy a reason not to use OSCAR? I would think absolutely not. The alternative is to fly absolutely blind. One does have to look at the results with some thought and purpose though. And remember the data comes from the machine not from the display software. If you go to a sleep specialist and do not take your SD card with you so they can look at it, they will see almost nothing for data. If you take your card, they will see the same as what OSCAR shows you.

Hope that helps some,

There are two main differences in a BiPAP compared to a APAP. First the BiPAP can go up to 25 cm for maximum pressure while the APAP is limited to 20 cm. But the higher pressure is not an obvious advantage in treating CA. More pressure often makes CA worse. The second difference is the ability to produce a higher differential between inhale and exhale pressure. A ResMed APAP can give you a 3 cm difference with EPR. The BiPAP machines can provide much more, and adjust it automatically during the night. Again this is not necessarily an advantage in treating CA. The higher the differential you use, the higher that IPAP has to go compared to the EPAP. The lower the EPAP the more obstructive apnea you get. The higher the IPAP the more CA you get. One can end up with the worst of both worlds (more OA and more CA) using a BiPAP to treat CA. I think a BiPAP is more for someone that has air flow issues (smoking, COPD, asthma, lung issues) than it is for treating airway collapse and CA. I recall one study that found in 60% of the cases CA got worse when the patient is moved from an APAP to BiPAP. It seems to me that if someone cannot achieve an AHI of less than 5 and the main issue is CA events, then it is time to consider an ASV like the ResMed AirCurve 10 ASV rather than a BiPAP.

Unfortunately most sleep professionals never look at the detailed data on the SD card. If they do not ask you to bring your SD card with you for analysis of the data, you have to be suspicious what they are basing their advice on.

Hypoxemia can have many causes. Living at a higher elevation can not only contribute to it, but it can also trigger central apnea events. I live at 2,000 feet of elevation, which is not that high, but I notice a reduction in CA event frequency when I travel to sea level. I have also seen other posters who have severe central apnea when they travel to higher elevations like Denver.

It is kind of complicated, but APAP machines for some time now automatically compensate for elevation. They maintain the same differential pressure between outside of the body and the airway pressure. So the same airway splint effect to keep the airway open is present at higher elevation. The O2 and CO2 balance in the blood however can be upset by it, and as a result trigger the instability in the automatic breathing control system that the body has. It can initiate the minute ventilation cycle that is illustrated in the SleepyHead graphs above. That in turn can cause central apnea events.

You may want to look at the posts by a user called "lakechapala". I recall he lives in Canada at a lower elevation but stays in the winter at Lake Chapala in Mexico. He had major issues with central apnea that he could adjust for at his lower elevation home in Canada, but not at Lake Chapala which is at about 4,500 feet elevation. He tried many things including, I recall, a medication prescribed for altitude sickness. In the end he bought a ResMed ASV machine and solved the problems. That said if you have respiratory issues like COPD, asthma, or other lung issues this may not be the best route for you. It depends what the root cause of the issues are.

I wouldn't recommend just buying an ASV either. They are not cheap and run in the range of $4500 or so. They also need a special heart function test run before you go on one. But, if your problem is central apnea, it may be what you need. My basic plan if I get to the point where I cannot average under 5 for AHI with CA being the largest factor is to ask my doctor to prescribe one, after getting the necessary heart function tests done to see if I am suitable to use one. A quote from one source:

"In May of 2015, ResMed, a global maker of CPAP and ASV devices, issued a statement cautioning against the use of ASV treatment in patients who had symptomatic chronic heart failure and reduced left ventricular ejection fraction (LVEF) of less than or equal to 45 percent (normal LVEF is between 55 and 70 percent). Respironics, another manufacturer of sleep technologies, followed up a couple of days later with a statement of their own discouraging use of ASV for at-risk patients while more studies are being conducted."

I am not sure if you have posted any OSCAR daily reports for comments. What you need to look for is to see if there is any relationship between pressure and when CA events occur. That will give you come idea whether or not you are pressure sensitive. It is common but not always the case.

What you have to do is identify all the CA events in a night and see what the IPAP pressure is at each event. This assumes the pressure is varying during the night. It can give you an idea if the CA events are more likely to happen at a higher pressure. There will not likely be any pressure spikes. The pressure will vary as the machine tries to prevent OA events. That is essentially what they are doing in a sleep titration test. They vary the pressure intentionally to see when you get CA events. The general idea is to get the pressure high enough to stop the OA events, but not high enough to initiate the CA events.

To post a chart save the daily report screen shot (F12 on a PC). With file explorer left click on the saved file and drag it into a full width message here. It should upload.

can't drag attachment from my pictures