Sleep study results and questions re: data

Hi everyone. I've been reading the messages here for a few weeks now and I'm amazed at the things I've learned from you all! I wish I'd found this website months ago because it might have helped improve my health and quality of living at a time when I was desperately seeking answers. What follows is a brief summary of the past six months or so of my life. If I could, I'd like to ask anyone who can spare the time (and is so inclined to read this), for your opinion(s) on a couple of things. I know this is going to be a long post so I'll try to summarize as best I can.

I was diagnosed with OSA about eight years ago and have been on CPAP @ 12 cm since that time. In October 2008, I began experiencing a constant mild - moderate sense of dizziness. I was still able to function but it was a very difficult. Over the next five months, I was evaluated by several well-respected physicians who ordered many, *many* tests in an effort to diagnose the problem. Every single test came back normal. Finally, one doctor asked when my last sleep study was. I hadn't had one since the original OSA diagnosis eight years earlier so he ordered a titration study. When I woke up in the sleep lab after the study, the tech wouldn't give me any info (as expected) but thankfully he did tell me that he needed to increase the CPAP pressure "a couple of cm". As soon as I got home, I changed the pressure on my CPAP to 14 cm (just a guess at that point based on the tech's comment). Within a couple of days the dizziness was gone and I felt normal again!! Unfortunately, I'll probably never know if (or what) damage may have been done during those five months.

Last month, I was finally able to meet with a physician who's considered one of the best in my area (Washington, DC) for the diagnosis and treatment of sleep disorders. During that appointment, I finally received a copy of the sleep study report (see below). The report was not dictated by this particular physician but rather one of his colleagues in the same office. Unfortunately, since I was seeing the report for the first time during that appointment, I didn't have the chance to spend a lot of time reading it and preparing questions. In a nutshell, he reviewed the highlights of the report with me and gave me a prescription for a new CPAP/APAP (mine was eight years old and lacked some of the newer "comfort" features) and suggested that I make a follow-up appointment in three months.

Here is the actual report:

----------

CLINICAL DATA: 36 year old male with a height of 5 feet 10 inches and a weight of 246 pounds (I'm working hard at trying to drop the extra weight) with a history of sleep apnea currently on CPAP at 12 cm complaining of dizziness and fatigue.

(1) A 16-channel monitored polysomnogram performed with a total time in bed of 428 minutes. Total sleep time was 351 minutes. Sleep efficiency was 82%.
(2) Sleep onset occurred at 23 minutes.
(3) REM onset occured at 162 minutes.
(4) Snoring was absent with CPAP in place.
(5) Single-lead EKG monitoring revealed a normal sinus rhythm with an occasional PVC.
(6) Sleep architecture with CPAP: 6% stage 1, 58% stage 2, 18% stage 3 and 28% REM sleep.
(7) Sleep-disordered breathing for the entire study revealed 38 central apneas, 11 obstructive apneas, and 17 hypopneas for a mean duration of 14 seconds. The longest hypopnea was 27 seconds, the longest apnea was 22 seconds.
(8) Saturation baseline asleep in stage 1 was 98% with an average fall with events to 93% and a nadir to 88% following a central apnea in stage 1 sleep in the supine position at 10:18 PM while on CPAP at 10 cm.
(9) Arousals totaled 88 of which 43 were related to sleep-disordered breathing events, and the remainder were spontaneous arousals. The arousal index was 23 arousals per hour of sleep.
(10) Leg movements were absent.
(11) Body position analysis revealed that all sleep time was spent in the supine position.
(12) CPAP distribution revealed that CPAP was introduced at 10 cm where the index was 56 events per hour. At 12 cm the index was 24 per hour. At 14 cm the index was 5 per hour. There were 12 central apneas, 7 obstructive apneas and 7 hypopneas at 14 cm. REM sleep was achieved supine with the lowest saturation of 93% at 14 cm. There was also 26% REM and 19% slow-wave sleep at 14 cm.
(13) Given the number of central apneas despite the persistent apneas and hypopneas, albeit mild at 14 cm, I would not recommend increasing the pressure further. I have reviewed the record personally and the patient seems to respond well to 14 cm with a large percentage of deep sleep. The index is borderline normal at a pressure of 14 cm.

CONCLUSION: Improvement in sleep apnea/hypopnea with CPAP pressure at 14 cm.

RECOMMENDATIONS: CPAP prescription at 14 cm with a) medium-sized mask of patient's choice; b) heated humidification; c) clinical follow-up

----------

About a month ago, I decided to replace my old CPAP with a Redmed S8 AutoSet II, the H4I humidifier and the Ultra Mirage II mask. I also purchased the ResScan 3.7 software and card reader. I've been reviewing the data from my new CPAP for the past three weeks and I'm a little concerned by what I'm seeing. If anyone can comment on the following, I would really appreciate your insights/opinion:

1. Since I started using the AutoSet II about three weeks ago (always in CPAP and EPR turned off), my AHI average is 9.6 with an Apnea Index of 2.7 and a Hypopnea Index of 6.9. On an average night, it looks like I am still experiencing 10 - 25 apneas at 14 cm pressure with 0 leak. I know these machines don't distinguish between obstructive and central apneas so I'm left wondering if these could be central apneas resulting from 14 cm pressure?

2. Now that I've had more time to review my sleep study, I notice that the study actually revealed more than triple the number of central apneas as opposed to obstructive apneas. Given that, does it sound like CPAP/APAP is an appropriate therapy for me? I could absolutely be wrong here but I thought I had read that BiPAP is more appropriate for the treatment of complex apneas?

If you've read this far, I sincerely thank you for your time! I know this is a lot of information to process but there are several people here who know much more about this than I currrently do and I'm really trying to educate myself about this condition so I can be my own best "advocate". I appreciate all of the information you guys have shared here. This website is really an amazing source of knowledge for this very serious problem.

I am new to this, too. But, like you, I thought BIPAP was the right tool for central apnea. Why don't you make another appointment and ask. My reading here suggests that raising CPAP pressure can trigger central apnea, so just raising your pressure might have risk. I would go back to the Dr. and ask the question.

Perhaps some of the experts here have some better answers.

Good luck!

Cecile

bmt22033 wrote: 1. Since I started using the AutoSet II about three weeks ago (always in CPAP and EPR turned off), my AHI average is 9.6 with an Apnea Index of 2.7 and a Hypopnea Index of 6.9. On an average night, it looks like I am still experiencing 10 - 25 apneas at 14 cm pressure with 0 leak. I know these machines don't distinguish between obstructive and central apneas so I'm left wondering if these could be central apneas resulting from 14 cm pressure?

2. Now that I've had more time to review my sleep study, I notice that the study actually revealed more than triple the number of central apneas as opposed to obstructive apneas. Given that, does it sound like CPAP/APAP is an appropriate therapy for me? I could absolutely be wrong here but I thought I had read that BiPAP is more appropriate for the treatment of complex apneas?

Hi, bmt. First, let me say I'm no expert; just another layperson diagnosed with Complex Sleep Apnea 19 months ago. Lots of apneas, hypopneas and centrals revealed in my sleep studies, along with Cheyne Stokes respiration. I've been on straight CPAP all this time (with a machine that was NOT data-capable - until a few weeks ago, when I purchased the one I have now), with several pressure changes.

My DME or doctor's office loaned me a Respironics Autopap four times, for a week at a time, set on Auto mode to determine why I was still so tired. I found that the Respironics Auto algorithm is NOT suited to my complex apnea and made me feel even more tired. (You'll note that the machine in my profile - the one I just bought - IS the Respironics Auto, but I have it set in Auto mode at the same min/max pressure of 12; so effectively, it's running in CPAP mode, but I get more data out of it. It's not the "right" auto machine for me, but it offered me the kind of data I've been hungering for since I started therapy. My sleep doctor was content with my being kept in the dark re: my treatment efficacy, but I sure wasn't, so I took it upon myself to find a machine that was data-capable. And the deal I got on this Respironics Auto - with a seller on CL - was a no-brainer.)

Research seems to be showing that some complex apnea sufferers are able to adapt to a fixed pressure over the long haul, and that seems to be the case with me. But CSA is tricky, and my current (finally!) successful treatment could give way to higher AHIs again and less effective therapy. So I'm keeping a close eye on my data.

AFAIK, if someone with CSA doesn't enjoy success with a fixed CPAP pressure, an ASV machine ("Adaptive Servo Ventilation") is the next step. Search the forum posts for "ASV" and you'll find many discussions about this. These machines have very sophisticated algorithms to deal with CSA. They won't increase pressure automatically to stave off obstructive events if doing so results in an increase in central apneas. There are a few people on the forum who use these machines. I questioned my new sleep doctor about getting one for myself, but she thinks my apnea is being controlled well enough on straight pressure. I'll keep monitoring my data to make sure I can stay ahead of the curve if CSA rears its ugly head again, in which case I hope my doctor will prescribe ASV for me. In the meantime, I'm happy to not be yawning all day every day.

If you'd like to read more about my own situation (and the responses from the "experts" on this forum about ASV and the treatment of CSA), check out this thread: viewtopic.php?p=359741#p359741. Or look for threads from forum members Kiralynx or OutaSync, both of whom utilize ASV machines.

Again, I'm no expert on the subject, and I trust others with more experience and knowledge will offer their assistance to you. I'll be following along, as I'm sure I'll learn a lot from your situation. Best of luck.

I notice that the study actually revealed more than triple the number of central apneas as opposed to obstructive apneas.

I'm not sure how you came to that conclusion.

The study report wrote:There were 12 central apneas, 7 obstructive apneas and 7 hypopneas at 14 cm.

(added emphasis mine).

That is the line you should focus on. I'm not a pro in this domain, and I may be wrong, but is seems to me those hypopneas should be considered obstructive, and counted among the total events.

Your doc seems to be going about raising your pressure carefully - some people stop having central apneas when they're used to the higher pressure. He also wants a "clinical follow up" meaning that he wants to know how you feel after the change.

Your data meanwhile is good: in the PSG your proportion of apneas to hypopnea was almost 3 to 1 -- but on your machine apneas are a small part of the total. And as you may have read, many people when using a ResMed have more hypopneas recorded that on other machines. So all in all, thoser numeric result look like they do for many others on ResMeds.

Are you feeling OK?
On ResMeds, like the one you have, pressure can be raised in 0.2 increments -- they're the only machines with that cpacity. If you're feeling OK, and adventurous, you may want to try that slight change: it may cause more apneas, (probably pressure induced) or it may help lower your hypopneas -- there's no telling which. Ask your doc what he thinks of that. Decimal pressure changes are still far from being the norm -- and I wouldn't be surprised if the lab didn't even have machine that could do that. I'm curious how you doctor will respond when you tell him you have a machine with a 0.2 cm/h2o increment.

Note that the report does not mention how much time you were tried at each pressure. Extarpolating AHI's from short time periods can be misleading.

Welcome to the forum -- I'm glad your new pressure solved your dizziness.

O.

I am no expert -- far from it -- but you might consider trying AutoSet mode with a range of 12 to 14. That way your average pressure might be lower, helping the centrals, but the machine could move up when you need it. Not that ResMed machines will not increase the pressure in response to an apnea if the pressure is 10 or above to avoid improper responses to centrals. But the do increase the pressure in response to flow limitations if the pressure is 10 or above. Since a flow limitation is indeed a breath, it must be obstructive as it cannot be central. And, (so the theory goes,) flow limitations usually preceed apneas.

I would see if others with more experience agree with the above before you proceed.