Sierra

I am not a medical professional and can't comment on the significance of O2 dropping that low for that length of time. It obviously is not ideal, but you would have to ask your doctor if it is a significant concern or not.

With respect to the machine only flagging a 10 second CA, I believe that is because you took a couple of partial breaths that were enough for it to start the count over again. I believe the machine starts the clock when the flow rate goes to zero, and at 4 second it starts a rapid pulse in the flow. It measures the impact that has on pressure. If it cause a larger pressure fluctuation, then it decides there is an obstruction. If the pressure does not have a significant pressure fluctuation then it concludes the airway is open. And when it lasts 10 seconds it flags it as an event. In the first section you can see the slight pressure fluctuation after 4 second, but the total event does not last 10 seconds, so it is not flagged. The smaller middle one did not last 4 seconds, so there is no flow pulse test. The last one starts the pulse after 4 seconds and lasts the full minimum of 10 seconds to flag the event as a CA.

I presume you have a BiLevel machine for a specific reason. Would it be to address central apnea issues? There are two ways that are often taken to address CA. One is to provide a pressure support (which I see is set at 4 cm) to help assist breathing. This appears to be the approach taken in your case. The other method used is to do everything possible to minimize pressure. In many cases the higher the pressure used the more likely central apnea events can occur.

What I see is that your EPAP pressure is very low, and it seems not much is needed to prevent obstructive apnea. However the 4 cm of pressure support forces IPAP to go much higher to 10 cm or so. You could ask your sleep doctor if setting the pressure support to zero would be a possibility. That would most likely keep the pressure up to 4 cm lower, and may reduce the frequency of central apnea events.

Hope that helps some,

Right now they are basically the same thing. However, the last time I tried to go to the SleepyHead download site, my browser flagged it as a non secure site and would not open it. The original author of SleepyHead I believe was Mark Watkins from Australia. He developed it as open source software, and made it free (donations only). Some others from the US got involved, and to make a long story short there was a falling out between Watkins and the US people. There were differences of opinion on what development was needed, who would do it, and who "owned" the software. Mark got frustrated and closed off development of the SleepyHead product. I still use it, and it works fine. So OSCAR started up by using the software developed by Mark and is apparently being improved. The big test will be when ResMed or Phillips releases a new machine, and whether the software will support it. Has not happened yet...

I think the first thing you need to keep in mind, is that you had a low level of apnea with an AHI of 8. In the UK that would not qualify for a CPAP. You don't mention what your AHI is with the CPAP, but even if it is <1, that is still not a very big change. In other words it is a bit of a stretch to say that the poor quality of your sleep (based on how awake you are the next day) was due to apnea. It would seems there must be other issues. I am not a medical professional, and can only give you suggestions based on my experience, and on a second had basis based on the experience of my wife. She was diagnosed with an AHI of >80. Now with a CPAP she is <1. She has noticed a huge improvement in her sleep quality. I was diagnosed with an AHI of 37. With CPAP I am now in the range of 2-3. I have not noticed a huge increase in my sleep quality, but my wife is appreciative of the termination of my snoring. But, I was sleeping quite well before CPAP, so to some degree there was not a problem to solve.

Long story, but I hear what you are saying, and don't have any simple answers either. Sleep can be elusive. I would encourage you to continue following up with your medical advisers. I have seen a useful website that was set up by a pharmacist and university professor that wanted to help people get a quality sleep without resorting to sleep medications. Here is a link to it:

Sleepwell, It's No Dream

Yes, I am sure the insurance companies like the cost of a home sleep study, which in my area of Canada is zero. What is a little more puzzling is the cost of the APAP machine if that is the outcome. On the surface of it, it seems the insurance companies (within their allowance limits) willingly pay $2400 or so for a machine. However, they are sold for about $800 on line. It seems hard to grasp why they would pay so much over the real price. Perhaps what we as the client see as the price paid by the insurance company is not the same as the actual money that changes hands behind the scenes. Perhaps we are getting a $2400 "benefit", that the insurance company really pays $800 or less for it.

There are differing opinions on whether HST overestimate or underestimate AHI. One study I read found that a HST underestimated sleep apnea frequency. To me that study makes sense. A home sleep study divides the number of events by the time in bed (TIB). A lab study divides the same number of event by time sleeping. A smaller denominator makes for a higher AHI.

Yes, my situation may have been a little different than typical. I was not in my opinion having sleep issues. I slept very well albeit with some snoring. I got cornered by my doctor into taking the screening test and failed. I very reluctantly went for the home sleep study, and really wanted to be found to not have sleep apnea. My wife was already using a CPAP and having to sleep with that contraption was the very last thing I wanted. Despite my wishes I failed the HST with an AHI of 37 or so. And here I am.

Short story is that I did not want to be diagnosed with anything. I do have to admit that I now sleep better and don't disturb my wife with snoring.

And as an aside a HST can identify central apnea events, or at least the Phillips Alice NightOne can. It measures breathing effort and air flow as well as oxygen levels, and body position. No air flow + No breathing effort = Central apnea event. Oxygen desaturation events can be also compared to apnea events for verification.

I'm not a medical professional and can't offer you any expert advice. About all I can do is relate my experience with some of these issues. I'm older and a few years ago I noticed my heart rate when exercising on the bike at the gym seemed to go too high and act irregularly. My doctor prescribed a Holter Test. The results came back that I had the occasional irregular heart rate, but that it was not abnormal. Some time went by, and I volunteered for a research test that was an MRI to determine the condition of my cardiovascular system. To do they test they had to slow my heart rate down, and used a beta blocker drug called metoprolol. Some time later again when I was having some blood pressure issues I asked about using a beta blocker like metoprolol as a second drug. My heart rate is also on the high side. He thought it may not be a bad idea. He actually prescribed bisoprolol, as he says it give a more uniform effect during the 24 hours of the day. I have been taking it since. So perhaps it is something to discuss with your doctor. A warning though. It can make your heart rate too slow, and promote drowsiness.

Hope that helps some,

Seems to me there are two issues here. One is simple and the other much more complex.

First there can be no justification in setting the diagnosis outcomes differently for women than for men. It could be that men are over diagnosed and women are not. Or, the reverse, men are diagnosed properly and women are under diagnosed. I suspect that was the main point of the article.

Second is the issue of whether or not we are over treating sleep apnea. Valid question, and much harder to rationalize. In the UK where their NHS pays for CPAP equipment, they will not give you a machine unless AHI is over 15. They don't treat mild apnea with a CPAP, unless you pay for it yourself. In North America government and private health care companies generally accept that treatement should start at AHI over 5, or Mild Apnea. Which is right is a worthy debate. Are the costs, no matter who pays for them, justified in preventing adverse outcomes?

I think there may be some misunderstanding as to what a home sleep study test is intended to accomplish. Basically it is a three step process. You are first given an Sleep Apnea Assessment Screening Test. If the results are positive for sleep apnea, and there are no other cardio vascular and other health complications, then a home sleep study test is ordered. The purpose of the test is to determine whether or not you have sleep apnea that needs treatment (AHI > 5 in most North American jurisdictions, but the UK NHS uses AHI > 15). The third segment of this process is to do a trial test of 2-3 weeks with an automatic CPAP machine to determine if a CPAP is suitable for treatment by examining the data collected by the APAP machine. The home sleep study is not intended to diagnose all the possible reasons why one might not be sleeping well, or any other medical condition. It is only intended to diagnose sleep apnea. If you have it, and the machine works, then one has a choice of buying a machine or having your insurance company buy one for you.

In other words it is only intended to diagnose sleep apnea, nothing else.

Machines have a minimum pressure of 4 cm. So there is no way you can monitor the frequency of events without some pressure. Normally one has the sleep study report which has the breakdown of the AHI which is without any pressure. Then if CA incidence goes up on treatment with CPAP, it becomes suspicious that pressure may be causing some of it. During the night when the pressure changes you can look at a SleepyHead report like the one above and determine at what pressure the incidence of CA events are worst and if the frequency goes up as the pressure goes up. The magenta event flags are CA events and the AHI in this example is virtually all CA.

It is somewhat normal for CA to go up somewhat on initiation of CPAP treatment, and in most cases it goes back down again after 6-8 weeks. However, in some it does not go back down, so they have to deal with it. Minimizing pressure is the most direct way. In serious cases an ASV machine may be used instead of a standard CPAP. A BiPap is often tried and it works in some cases but not all.