grizfan wrote:Is it normal to have an occasional 'bad night'?
Short answer: YES it's normal to have the occasional 'bad night'.
Sometimes the cause of the bad night is easy to identify: You're coming down with the flu. You're dealing with some significant pain issues (I had some pretty high AHI's after breaking my pinky about 4 years ago.) You're under stress and you're simply not sleeping too well. You had one too many drinks during the evening. You're taking a new medication that affects your sleep. Spring allergies are really, really bad. Fall allergies are really, really bad. And so on and so forth. Sometimes there's no identifiable cause: Pugsy used to blame her occasional bad nights on a visit from the aliens.
To complicate things, I had a 10 day business trip wedged in the middle of my first 28 days, which included not only getting used to a hotel bed, but a 7 hour time zone difference, and an entire night of therapy lost due to an overnight long haul flight (Seattle to Amsterdam). Despite all of this, my numbers seem to be getting better. Based on my AHI numbers, I had one really bad night (AHI of 16.58), but the rest of my trip, my AHI score never went above 5, with most scores within .25 above or below 2. The night before I flew home, I spiked to a score of 8.95, but since returning, I seem to be drifting lower, with scores of 3 or lower, and 0.91 last night. The overall trend seems positive. But, I'm a bit worried about these spikes.
My guess is that all the traveling you've been doing (along with simply adjusting to CPAP) is more than enough to explain the bad nights you've had so far.
Some people wind up fine tuning things to where they almost never see a night with an AHI > 2.5. But most of us do see the occasional night where the AHI > 5.0. To put this in perspective for you, I just looked at my own overview data in SH for the last year. There are 10 days out of the last 365 where I had an AHI > 5.0. This January I even had a string of 3 of them in a row when I was probably fighting a pretty severe head cold. So if the trend is going down and on the vast majority of days your AHI is below 2, then I wouldn't necessarily worry (yet) about the few days you've had with pretty high AHI's. The traveling itself can explain a lot of issues and that may be part of why the AHI was higher on some of the days of your trip. (Here again, I've noticed that my AHI often spikes when I'm traveling for a day or two.)
How long does it typically take to get 'settled in'?
It can take anywhere from a couple of weeks (if you are very lucky) to a couple of months (kind of standard) to more than 6 months (if you're not lucky). Your extended trip may set you back by a couple of weeks.
Am I right in attributing some of this variance to the disruption caused by my business travel at such an early stage of therapy?
Yep, I think you're right to attribute the variance to the travel.
You may find that whenever you travel that your AHI becomes more variable for the duration of the trip. And then takes a couple of days to settle back down once you get home. We don't sleep the same way when we're not sleeping in our own bed. And any differences in sleep can potentially influence the apnea on that particular night.
As for your data:
3/25
This night's data looks pretty good to me. There's a bit of snoring that triggers the first pressure increase at 3:30. There's one or two Hs plus some snoring at around 4:15 that triggers the second pressure increase. All the rest of the events are isolated and the PR search algorithm is not finding any real reasons to increase the pressure from your minimum pressure of 6cm.
So the real questions for this night are: How well did you sleep
subjectively? Did you wake up feeling more rested than when you went to bed? Did you wake up feeling like the sleep you got was restorative sleep?
If this is a typical night's data, then I'd say that on paper you've pretty much got the settings optimized.
3/23
On the surface, this night's data looks like a mess. But ....
Most of the messiest parts are confined to the first 90 minutes of the night.
How long do you think it took you to fall asleep? There's a lot of stuff that looks like it could be Sleep-Wake-Junk (SWJ) between the beginning of the night and 22:20. If you were doing a lot of tossing and turning at the beginning of the night, I'd write off the cluster of OAs scored at 22:-5-22:15 as false SWJ events---i.e. events that probably would not have been scored on a PSG because you were not asleep according to the EEG.
More problematic is the period 23:00-23:30. It looks like the machine is have a really hard time tracking your breathing during this time frame. That can happen when the leaks get too large, but your leak rate is not being flagged as an official large leak by SH. Nonetheless, there's evidence in the leak graph that the leaks are growing and, to be honest, I'm a little bit surprised that an Official Large Leak was not scored just after 23:30 when the total Leak rate is close to 70 L/min. (Then again, the pressure is at 12cm and the PR machines have a higher tolerance for the excessive leak rate at higher pressures.) I see this kind of bizarre "lose track of my breathing" stuff in my own flow rate data from time to time. The first several times it happened, it freaked me out. My DME calls them "patient disconnects", which I resent since the problem is not caused by the patient taking the mask off. Still, our machines are not perfect and for whatever reason, the machine has lost track of your breathing during this time frame. The OAs scored between 23:15 and 23:30 may or may not be real. The machine still seems to be having trouble tracking your breathing, but it is finding some breathing to track by this point. However, when the machine is having a tough time tracking the breathing correctly, it also has a very, very tough time determining when the airflow into your lungs actually has dropped enough to warrant scoring an apnea vs. the air flow data is just not there because the CPAP is lost in the first place. Zooming in on the flow rate data for the period between 23:00 and 23:30 needs to be done in order to assess whether that nasty cluster of OAs is due to "bad data caused by the patient disconnect" or due to real OAs or a combination of the two.
By 23:05 or so, the machine has finally sorted out whatever caused the problem with tracking your breathing. And it's now tracking your breathing properly again. The rest of the night is still "busy" in terms of events, but it's not the disaster that the overnight summary numbers make it out to be. You clearly turned the machine off and back on around 1:30 and again around 4:15-4:30. Bathroom breaks by chance? Or did you just wake up and need a short break from the machine?
My guess is that you were pretty restless this night. That might also explain some of the rattiness in this night's data. Or perhaps you had more alcohol during the evening that you usually consume? That too can cause pretty ugly nights since alcohol can aggravate the tendency for the airway to collapse as well as depress our tendency to wake up earlier during an event.
Finally, if you were seeing this kind of data on
most nights (as 4-6 nights every single week), then there would be some evidence that the min pressure setting might ought to be increased a bit.
