Would like input on increasing AHI

[jilliansue]

Hello everyone,

During the past few weeks, my AHI numbers have been high. Not every night, but most nights. They used to be consistently below 5.0, but recently that is a rarity. Last night, 17, and the night before, 11. Leaks have at times been somewhat high, but not always. Last night, leaks were .10, so pretty minimal, and it does not seem that the high AHI of 17 would be related to a leak rate of .10.

My machine is not compatible with SleepyHead so I cannot post graphs. I will be eligible for insurance to pay for a new machine in 2 months - can't wait! And at that time I will begin using SleepyHead.

The only thing that has changed is that I have lost 15 pounds. I would not think that would make a difference. My question is, should I try increasing or decreasing my pressures? I have had them set the same for a couple of years now, at 14 inspiration and 11 expiration, that has worked well up until very recently. I have been using a different pillow, but have not changed my sleeping position.

Thank you in advance for any input, insight, or advice.

[Julie]

Have you looked at leaks? Losing weight can make a big diff. in your face and therefore the seal.

[jilliansue]

Hi, Julie,

I like the black cat, and I liked the white one too!! I have thought about tightening the headgear as I think the mask has been leaking a bit more. But last night, for example, leaks were .10 and yet AHI was 17... The AHI seems high for the amount of leak.

[Pugsy]

The 0.10 L/sec your machine shows is well under large leak territory which is 0.40 L/sec. I don't see the problem being the leak. That's a 95% number which means you were at or below that number for 95% of the night.

If it were me I might try just a little more pressure to see what happens.

[jilliansue]

Thank you, Pugsy. By what increment would you recommend increasing the pressure?

[Pugsy]

I normally suggest small increments because it's an easier adjustment and we never know how much just a little change might help or not. I think in this situation at least 0.5 or 1.0 to both EPAP and IPAP.
Without knowing the event categories it's hard to get a handle on thing and those S8 machines were notorious for aggressively scoring hyponeas.

Were you give the ST model because of lung issues or just problems exhaling in general?

[jilliansue]

They gave me the ST model because of central apneas. Or at least that is what I surmise. I never met the sleep doc, it was a traveling sleep lab with tech. She told me during the titration study about central apneas and that "I wasn't even trying" to breathe. At that point, she switched it to bi-level and my results were much better. I am thinking I will get either an S9 VPAP ST or an Aircurve ST since I have had good results with the S8. Or so I think anyway! It is interesting to hear that the S8 aggressively scores AHI. Last night's AHI was 17, and the AI was 0.

Do you have any recommendation on what to replace the S8 with?

Thank you!

[Pugsy]

If your original diagnosis was where you had both obstructive sleep apnea and central sleep apnea then I would think the AirCurve 10 ASV would be a good choice since it is able to deal with both easily and quickly. Especially useful when people have just obstructive sleep apnea to start with and only develop the centrals after the cpap pressure is introduced.
If it was just centrals only then I think they tend to go with the ST model but they could do the ASV model. I am not sure what causes the differentiation in the choice.
The ST doesn't offer the variables that the ASV offers but maybe you don't need those variables.

So it really comes down to what your original diagnosis was. If the centrals only appeared after the introduction of cpap pressure then I would be extremely cautious increasing the pressures. We don't know how much of that AHI you are seeing is central in nature and getting thrown in to the hyponea basket. If it is central in nature more pressure is unlikely to fix it and could potentially make things worse if cpap pressure is the cause of the centrals or more pressure makes more centrals. Just be careful.

[jilliansue]

This is from my initial sleep study:

FINDINGS: This was a diagnostic study. Much of her abnormality was seen in the last 2 hours of the night, including turning supine for the only portion of the night during this time, but also for some reason her difficulty on her left side was worse late in the night than it was early in the night.

Cardiac rhythm was normal sinus rhythm. Periodic leg movements were minimal, averaging 8.7 per hour.

Total sleep time was 6.5 hours with a sleep efficiency of
87%. Regarding sleep stage distribution and percent of total sleep time, Stage Nl sleep was 7%, Stage N2 was 65%, Stage
N3 was 9%, and Stage R was 18% of total sleep time.

Regarding respiratory events there was 1 obstructive apnea,
33 central apneas that occurred mostly "post-arousal."
There were 184 hypopneas and 60 additional respiratory effort-related arousals. This gave an apnea-hypopnea index of 33.3 events per hour, and a respiratory disturbance index
of 42.4 apneas, hypopneas, or respiratory effort- related arousals per hour. 4% 02 desaturation was required for definition of hypopnea.

Her difficulty was worse in REM sleep compared with non- REM. Apnea-hypopnea index in REM sleep was 60 per hour, compared with 27 per hour in non-REM sleep. It was also worse supine
compared with non-supine. Supine apnea-hypopnea index was
106.5 events per hour during the 1.25 hours she was supine.
During the 4.5 hours she was on her left side apnea­
hypopnea index was 15 per hour. During the 1 hour she was on her right side apnea-hypopnea index was 20 per hour.

ASSESSMENT: Severe obstructive apnea-hypopnea syndrome with an apnea-hypopnea index of 33.3 events per hour, and a respiratory disturbance index of 42.4 events per hour. Lowest oxygen saturation of 74 %. Most of the desaturations below 80% occurred in the last 2 hours of the night during which time she was mostly supine.

[Pugsy]

Looks like primarily OSA and the centrals were post arousal...not sure as to the significance of that but using the ST machine offers the ability to have the backup rate to help you breathe should the centrals be a problem. Or at least I think that is the reasoning behind it. EPAP and IPAP are fixed like they would be on a regular cpap machine to treat the obstructives and the ST has the backup rate available to act sort of like a ventilator and give you an extra push if the centrals cause your respiration rate to drop too low. Regular CPAPs can't do that.

I don't know what would have changed with the recent weight loss to cause an increase in pressure needs unless the tissues just got saggier with the weight loss (sort of like our underarms do with weight loss).
Since your centrals appear to be primarily post arousal and related to an awakening from something and not made worse by the pressures then I would think it would be safe to proceed with a small increase in pressure to see if your AHI responds or not. I would still go with small change though...like 1.0 for each setting. While the general rule of thumb is EPAP for obstructive and IPAP for hyponeas I don't know that I would increase IPAP only in this situation.
Sometimes when the pressure support (that difference between EPAP and IPAP) is too much it can cause unstable breathing and lead to centrals. So in this situation I would keep the pressure support constant and work on the hyponeas with both EPAP and IPAP increase.

As always...if you feel over your head and things aren't going well you should probably talk to your doctor. Your situation is not a common situation like just plain old vanilla OSA so I would be cautious about DIYing things.

[jilliansue]

Pugsy, Thank you so much! I truly do appreciate your time and advice!!