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+--- Thread: LOW AHI, but now waking up three times every night. (/Thread-LOW-AHI-but-now-waking-up-three-times-every-night)
LOW AHI, but now waking up three times every night. - mdh235 - 07-07-2014
After nine months of experimentation with different machine settings and over half a dozen masks, I've finally hit the sweet spot in my therapy.
The mask fits with low leakage, and my AHI is closer to 0 than to 1 most nights now.
Of course, it can't be that easy and now I have another problem. After months of waking just once, or maybe twice a night. I now wake up three times every night, usually at two hour to two and a half hour intervals.
While this hasn't resulted in my being sleepy or fatigued during the day (yet), I'm at a loss to understand why it's started now.
Looking at my apnea events, it appeared I was waking up when the machine ramped up the pressure, so I set it back to CPAP mode at the 95% pressure. No change in the number of wake ups.
If anyone has any ideas about this I'd love to hear them. I'm so close to getting this condition under control now the number of wake ups is definitely a step in the wrong direction.
RE: LOW AHI, but now waking up three times every night. - zonk - 07-07-2014
I do not think its a problem if you,re going back to sleep and does not seem affecting how you feel during the day
RE: LOW AHI, but now waking up three times every night. - zonk - 07-07-2014
(07-07-2014, 07:13 PM)mdh235 Wrote: Looking at my apnea events, it appeared I was waking up when the machine ramped up the pressure, so I set it back to CPAP mode at the 95% pressure.The machine also increase pressure in response to flow limitation. Not necessary apply to everyone but I,m better off starting with minimum pressure set at or close to 95% pressure so the machine get on with the job and maximum pressure a bit higher to finish the job in case sleeping supine or having glass of wine too many
RE: LOW AHI, but now waking up three times every night. - mdh235 - 07-07-2014
I've found that my machine will almost always hit the maximum level I set, even if in CPAP mode my apnea is controlled at a lower level.
For example, if my range is a narrow 12.4 to 12.7 it will spend most of the time at 12.7 and my AHI will almost always be below 1.
If I increase the top end to 14, sure enough that's where the machine wants to be most of the time, even though my AHI may actually increase due to an increase in centrals.
It took me a long time to figure that out, because I assumed the machine knew what it was doing.
RE: LOW AHI, but now waking up three times every night. - Sleepster - 07-07-2014
(07-07-2014, 07:13 PM)mdh235 Wrote: Looking at my apnea events, it appeared I was waking up when the machine ramped up the pressure,
Obstructive apnea occurs when the airway is closed off, hypopnea when partially closed off, but you can also have flow limitation when it's only slightly closed off.
Flow limitation could be what's waking you up. Flow limitation could also be what's making your pressure ramp up. When you zoom in on the flow graph look for signs of flow limitation at times just prior to the pressure ramping up. It shows up as a reduction in the amplitude or a change in shape of the upper part of the flow wave. You can also see it in the flow limitation graph.
Snoring is another indication of flow limitation so look for that in the data, too.
But as Zonk says, it's nothing to worry about. You could take sedatives to help you sleep through those episodes, increase your exercise regime, diet to lose weight, or all of the above. Or just put up with it.
RE: LOW AHI, but now waking up three times every night. - Sleepster - 07-07-2014
(07-07-2014, 08:47 PM)mdh235 Wrote: If I increase the top end to 14, sure enough that's where the machine wants to be most of the time, even though my AHI may actually increase due to an increase in centrals.
It took me a long time to figure that out, because I assumed the machine knew what it was doing.
The reason it attempts to determine centrals is so that the pressure-adjusting algorithm can ignore them and respond only to obstructives.
Look at those centrals and see how long they last. If they're just a few seconds long and they don't wake you up, they may not be anything you need to worry about. You could use an oximeter to make sure of that.
RE: LOW AHI, but now waking up three times every night. - zonk - 07-07-2014
(07-07-2014, 08:47 PM)mdh235 Wrote: If I increase the top end to 14, sure enough that's where the machine wants to be most of the time, even though my AHI may actually increase due to an increase in centrals.machine wants to go higher to combat flow limitation (FL), higher it goes, here comes pressure induced central apnea
all about compromise and whats easier to live with, FL or few centrals?
have you experimented with epr? epr at level 3, pressure drop at exhale by 3
RE: LOW AHI, but now waking up three times every night. - mdh235 - 07-08-2014
(07-07-2014, 10:04 PM)Sleepster Wrote: But as Zonk says, it's nothing to worry about. You could take sedatives to help you sleep through those episodes, increase your exercise regime, diet to lose weight, or all of the above. Or just put up with it.
Hmm. Tough decision. I think I'll just put up with it, at least for now.
Thanks for all the advice. You too, Zonk.