Overnight Pulse Ox Test - Updated Sat Night

Good Morning Everyone!

I opted to do another test without changing any parameters. Last night's test was like most of the others in recent days -- indicating 3 desats, down to a low of 84%, averaging 21.3 seconds in length, with a total time in events of 1.1 minutes. I haven't taken the time to investigate the desaturations in the software in 10-second increments, but will probably try to do that later today if I get to it.

I have tried to hold my breath to see if the monitor will indicate desats and I can't do it either. I can't hold my breath very long and holding it for the time I'm able doesn't do it. Weird.

I'm not terribly happy about these desats, but am really not sure what would be done about them. I don't know what settings on the ventilator they would change to compensate.

Are you on oxygen too? I forgot

gvz, I, for one, am glad you jumped in.

As I said, I don't really understand how oximeter algorithms work to turn infrared light intensity into a printed report. Obviously it isn't good for the heart and brain to lack oxygen. But I don't know how well the O2 sat. measured in my nailbed reflects the O2 level in my brain tissue (because my physiology compensates for low O2 by shunting additional blood to my brain and heart). I don't know how valid the arbitrary cutoffs between normal and abnormal (4% decline, 10 second durations, 88% critical threshold, etc.) really are.

As you say, everyone is different, and your experiment turned out different from mine. I wish I knew what the normal variation of O2 drops in response to breath holding are. Introduce more variables, such as heart or lung disease, and I understand even less.

I don't know how the CMS is manufactured, their tolerances and quality control, or how often a defective one gets into the stream. It's even possible you and I have the same desat curves with breath holding, but our machines are responding differently.

So far, since there's so much I don't understand, I have just been using the oximetry report as a kind of confirmation. If a desat occurs at the same time as an obstructive event tag on Encore View, they confirm each other. If Encore View tags a CA, but there's no desaturation, I suspect it's an artifact. I don't know how much weight to give the absolute numbers. (In other words, if you have a desat to 75%, and I have a desat to 83%, does that mean your SDB is worse than mine? )

I'd be glad if some others jumped in.

echo wrote:Are you on oxygen too? I forgot

Yes. I've been on oxygen since I had the bipap machine. When I was switched to the ventilator in February, we kept the oxygen.

Well, last night's test, done with standard "event" criteria of drop of 4% for 10 seconds resulted in ONE event down to 84% that lasted 51 seconds.

I'm wondering what you guys think, knowing that my situation is a neuromuscular disease causing muscle weakness.

Is this serious enough, being that I seem to have desats into the lower 80's almost every night, to report to my doctor to see if she wants to make adjustments? Or should I let it go and wait until the report indicates numerous desaturations EVERY night?

Madalot, I just want to say I've been following your posts and have reviewed a lot of your prior posts--and I wish I had read them before I posted my last excnagne about your oximetry. My heart really goes out to you for all you have to deal with. I am grateful you seem to have a competent, caring medical team

I wish I could offer something specific, but I just don't understand enough about ventilators and mitochondrial myopathy. Having said that, I can see why you're not comfortable with nightly desaturations, and I don't understand why they happen with the ventilator and O2 supplement controlling the amount of O2 you breathe each minute.

In answer your immediate question, I think you should consult your medical team about the desaturations. You already have a plateful dealing with the myopathy. You need your mental faculties to be as sharp as they possibly can be. A previous poster pointed out what Stephen Hawking has been able to accomplish, despite ALS. If you have the opportunity to bring up Hawking's example in a conversation with your doctor, it might help her to appreciate your concern.

M.D.Hosehead wrote:Madalot, I just want to say I've been following your posts and have reviewed a lot of your prior posts--and I wish I had read them before I posted my last excnagne about your oximetry. My heart really goes out to you for all you have to deal with. I am grateful you seem to have a competent, caring medical team

I wish I could offer something specific, but I just don't understand enough about ventilators and mitochondrial myopathy. Having said that, I can see why you're not comfortable with nightly desaturations, and I don't understand why they happen with the ventilator and O2 supplement controlling the amount of O2 you breathe each minute.

In answer your immediate question, I think you should consult your medical team about the desaturations. You already have a plateful dealing with the myopathy. You need your mental faculties to be as sharp as they possibly can be. A previous poster pointed out what Stephen Hawking has been able to accomplish, despite ALS. If you have the opportunity to bring up Hawking's example in a conversation with your doctor, it might help her to appreciate your concern.

Thanks for chiming in on this. I appreciate the input. To be honest, I think these types of myopathies are rare enough that even the most experienced doctors don't have all the answers as to what is going on and what the future holds. My newest neurologist said he's got about 3 other patients in the same boat as I am -- suspected Mitochondrial Myopathy, but they can't confirm the diagnosis. I'm not sure all of his other patients have breathing problems, but he didn't seem at all surprised that I do.

I think one of the reasons that I'm not sure I need to address this with my pulmonologist YET is that even though there are desaturations every night, this may be as good as we can hope for at this juncture. I'm already so far past the bipap machine as far as equipment sophistication and capabilities and yet I'm still experiencing a few desaturations into the lower 80's.

This is really tough for me to decide whether to talk to them about it or let it ride a little longer. I still have that nagging threat in the back of my mind from a few months back. I know I always have the ability to say No, but being told (not by my doctor) that if I keep complaining, they'll just get fed up and recommend a trach and be done with all this stuff. That's a road I am just not prepared to go down now -- if ever.

But thanks for the input and positive support. I really appreciate it.

Madalot wrote: I'm wondering what you guys think, knowing that my situation is a neuromuscular disease causing muscle weakness.

Is this serious enough, being that I seem to have desats into the lower 80's almost every night, to report to my doctor to see if she wants to make adjustments? Or should I let it go and wait until the report indicates numerous desaturations EVERY night?

Madalot, I'm another person who doesn't understand enough about your condition or its treatment to offer any real expert advice. But I can at least offer you my support and tell you what very little I THINK I happen to know about PAP-modality based ventilator therapy--- with respect to progressive neuromuscular disease (NMD) in general:

1) Accommodation of muscular Work of Breathing (WOB) itself is the ventilator's primary objective in NMD cases involving muscle weakening
2) In progressive NMD, the ventilator might need adjustment to mechanically offload more and more of the patient's neuromuscular workload
3) When traditional BiLevel PAP modality is employed, IPAP (inspiratory pressure) is typically increased to provide more assistance with that Work of Breathing (WOB)
4) When AVAPS modality is employed (your case), then IPAPmax gradually and automatically rises to meet Vt (tidal volume) targets, but when that doesn't work:
5) Review and manual adjustment of EPAP (for airway stenting), IPAPmin (for airway stenting and/or minimum-needed Pressure Support), and/or IPAPmax (maximum-needed Pressure Support) is probably necessary
6) Rise Time, BPM, and I-time are also worth reviewing according to the AVAPS titration protocol on page 16 of 36 below
7) Ventilator adjustments to accommodate WOB issues can SOMETIMES introduce "iatrogenic" or unintentional central breathing problems----so perfect therapy is not ALWAYS possible

http://www.nwrei.org/downloads/Educatio ... 0AVAPS.pdf

Madalot, I realize you don't care to risk alienating your pulmonologist with what she might view as excessive questions... But I think at the very least I would fax my reports and questions in for her review. I'd also follow up with a phone call after she had time to thoroughly review my reports and questions.

Good luck, my friend! We're here and pulling for you as always...

Madalot wrote:Well, last night's test, done with standard "event" criteria of drop of 4% for 10 seconds resulted in ONE event down to 84% that lasted 51 seconds.

Madalot, I had a thought toward discussing your SpO2 data with your doctor. In light of the AVAPS titration protocol excerpt below, you might want to ALSO keep an eye out for 5-minute durations spent at or below 90%. That 5-minute@90% threshold is apparently considered a crucial AVAPS manual adjustment benchmark:

AVAPS titration protocol wrote: Unable to maintain SpO2 >90% for 5 continuous minutes?

AVAPS protocol's YES decision branch wrote: 1. Increase tidal volume to patient comfort by 10 ml increments for optimal therapy
2. Assess EPAP, consider increase
3. Assess rate, consider increase
4. Consider adding supplemental O2

Of course, validation of all the protocol steps occurring BEFORE the above 4-step sequence would be prerequisite.

P.S. Hey! Sink kitties are back!

-SWS,

I remember your liking "sink kitties." That was in the back of my mind when I put them back!!

Thank you for posting the information you did in the last two posts. The information is extremely helpful to me and makes a lot of sense. The criteria listed in your last post of staying at 90% or lower for 5 minutes doesn't seem to apply. It looks like I tend to stay around 95% most of the night, but have these drops that only last a minute or so. She may not feel that there are enough or that they last long enough to warrant changing the therapy at this point.

However, based on what you've posted, I think it might be prudent for me to ask my doctor what "benchmarks" would merit making changes to the existing therapy, providing her with what I have as of this point. If I'm going to be proactive in monitoring the effectiveness of my therapy, I need to know what SHE believes are changes that warrant modifying the existing settings.

But I plan to print out your last two posts for reference purposes because they have a lot of "meat" to them -- and I thank you from the bottom of my heart for taking the time to do it.

I appreciate the help and support I get. I'm desperately trying to balance keeping an eye on things, but not becoming obsessive about it. It's a fine line.

Hi Madalot, I really cannot offer more at this point beyond encouragement.... and some laughter. "sink kitties"

echo wrote:Hi Madalot, I really cannot offer more at this point beyond encouragement.... and some laughter. "sink kitties"

Echo -- sometimes encouragement is just as helpful -- if not more so. Thank you. I remember that people liked sink kitties. Even though they're aren't my cats like the last two I had up, I think they're adorable.

I cannot, for the life of me, figure out what the heck is going on. I had a very unpleasant night last night. We cleaned my mask and it was leaking pretty badly, but my husband was already asleep and I didn't feel like getting up or waking him up. But that darned mask was driving me insane with noises (we'll check it tonight and replace it if necessary). I'm guessing that it wasn't put back together quite right and didn't have a good seal.

My overnight from last night showed no desats and nothing below 90% all night. The night before wasn't too bad with one drop to 89% that lasted 33 seconds. The night before that was one drop to 84% that lasted 51 seconds.

I seem like I am all over the board.

Maybe at this point, it might be better to just stop testing for a few weeks and just not worry about this for a while.