Bad sleep study titration? SpO2 drops...

[raisedfist]

I was titrated on bi-level at pressures of 13/8 to treat sleep apnea and also hypoventilation. The report states at these therapeutic pressures my oxygen saturation stayed above 92% except for transient REM Periods, where it dipped to 88-89% and then went back up. But, in looking at the report the SpO2 graph is only steady with no dips until the last hour of recorded data or so...this does not seem to me to be reliable evidence that these pressures are therapeutic during sleep. Maybe I just didn't problems breathing during that hour...I have hours where the graphs look great, then there is a huge downward spike that's sustained, and then it goes back up.

I have still remained rather symptomatic after 39 days of 100% use. I wake up with headaches often and don't feel refreshed most of the time. I have no intolerance to the device itself - I wear it for more than 8 hours most nights.

I used my recording pulse ox last night (CMS50-F) out of curiosity, and low and behold, my oxygen saturation levels go below 88% for 6 minutes out of 4.5 hours sleeping. Sustained dips even while AHI = zero. My average AHI is 0.1 after 39 days of data. So the oxygen saturation dips, especially sustained for several minutes, seem to be hypoventilation that is not adequately treated. I saw two dips that stayed under 88% for 2-4 minutes at a time. Obviously it's better than pre-treatment, but nowhere near optimal either. I am assuming the headaches are CO2 headaches. I do feel better throughout the morning as I become more active, so I assume my body compensates during wake hours to blow off the CO2.

I have a follow up next week so I am going to record several nights with the pulse ox and bring print outs of the SpO2 reports to show them. This is hard because I often wake up in the middle of the night and just lay there for 1 hour or so before falling back asleep. I am only able to see the physician assistant because the actual Dr. is booked up for months.

Very frustrated because that was my 3rd sleep study (different facilities each time - I have moved a lot ), and I've used bi-level for about a years time and have tried seeing different sleep docs who specialize in pulmonology as well, and none seem to care that much about my problems. Very disappointed in sleep medicine in general. Seems like a scam - once they get you as a referral to insurance they seem to not give a rats a$$.

I am considering experimenting on my own and raising the IPAP value because I read this increases ventilation (tidal volume), CO2 clearance, and helps control the hypoventilation through a higher pressure support.

I don't want get in trouble with compliance issues though, by changing the pressures. Is it okay to make changes? Or should I just wait until next week, given that it's not that long from now? I also assume I shouldn't make changes every night based on the data, that I would need at least several nights to analyze before making any such tweaks?

[palerider]

I don't want get in trouble with compliance issues though, by changing the pressures. Is it okay to make changes? ?

it does get tiring answering the same questions over and over from people that don't read, or can't use either the built in search, or site specific search from any of the big search engines.

especially for such a commonly discussed issue.

[Julie]

Not a problem. The insce co. couldn't care less what your pressures are or if you change them... it's your treatment and your life, don't worry if your DME or doctor tries to intimidate you or treats you like an idiot to keep their own little mystery/god complexes going... we all change our pressures and no one has had any problem.

[raisedfist]

Thanks. Sorry Palerider, sometimes frustration leads to frantic typing and therapeutic ranting without doing basic preliminary searching.

I can't even figure out why they raised my EPAP at all. In all the titrations and recorded data I've never had concrete obstructive apneas, all the AHI has always been made up of hypopneas (which I am pretty sure are treated with IPAP in bi-level). My only guess is maybe a higher EPAP helps you wash out the CO2?

According to the Resmed sleep titration guide, you only raise EPAP for obstructive apneas. Practically everything else is handled by IPAP increases while keeping EPAP the same. It even says for oxygen saturation < 90%, in the absence of respiratory events (AHI related events), raise IPAP until oxygen saturation is >= 90% to correct the hypoventilation.

I wish I could do a in-hospital stay and they would do more than one night of testing and just get it right once and for all.

[palerider]

Thanks. Sorry Palerider, sometimes frustration leads to frantic typing and therapeutic ranting without doing basic preliminary searching.

you hurt yourself the most by doing that, it doesn't allow effective thinking. before doing that again, sit back, take 10 slow, deep breaths, calm down, and then think.

I can't even figure out why they raised my EPAP at all. In all the titrations and recorded data I've never had concrete obstructive apneas, all the AHI has always been made up of hypopneas (which I am pretty sure are treated with IPAP in bi-level). My only guess is maybe a higher EPAP helps you wash out the CO2?

According to the Resmed sleep titration guide, you only raise EPAP for obstructive apneas. Practically everything else is handled by IPAP increases while keeping EPAP the same. It even says for oxygen saturation < 90%, in the absence of respiratory events (AHI related events), raise IPAP until oxygen saturation is >= 90% to correct the hypoventilation.

as far as I'm aware, the resmed titration guide is right but focused on apnea. if you do some research on bilevel therapy, what you find out is that when using bilevel to treat respiratory distress, you raise epap to increase oxygenation, and you raise ipap to increase co2 blowoff.

when treating apnea, epap maintains the airway opening so it doesn't close between breaths, and ipap takes care of hypopneas by increasing airflow. (and enough forced ipap can ventilate you during central episodes.)

so, raise epap till obstructive apneas stop, then raise ipap till hypopneas stop.

hypoventilation is not normally an issue, absent of other co-morbidities.

I wish I could do a in-hospital stay and they would do more than one night of testing and just get it right once and for all.

wistful thinking.

the best place to figure out what pressures you need is with your own machine, in your own bed. not wired up like a lab rat in unfamiliar circumstances.

[raisedfist]

you hurt yourself the most by doing that, it doesn't allow effective thinking. before doing that again, sit back, take 10 slow, deep breaths, calm down, and then think.

I will definitely do that. Thanks again - sometimes I need an outside reminder.

as far as I'm aware, the resmed titration guide is right but focused on apnea. if you do some research on bilevel therapy, what you find out is that when using bilevel to treat respiratory distress, you raise epap to increase oxygenation, and you raise ipap to increase co2 blowoff.

that sounds correct. I have read about bi-level therapy. I have a restrictive lung disorder, and in reading about hypoventilation - what happens is that CO2 rises as a result, which then effects oxygenation. this can happen in the absence of obstructive apneas/hypopneas.

my basal SpO2 on room air is 93% and I don't ever really have any recorded respiratory events (my AHI has been 0.0 - 0.1 every night).

when treating apnea, epap maintains the airway opening so it doesn't close between breaths, and ipap takes care of hypopneas by increasing airflow. (and enough forced ipap can ventilate you during central episodes.)

so, raise epap till obstructive apneas stop, then raise ipap till hypopneas stop.

hypoventilation is not normally an issue, absent of other co-morbidities.

I suffer from nocturnal sleep-related hypoventilation due to a restrictive chest wall disorder. my cardiologist said this is sleep-related respiratory failure, which of course I would love to resolve as it effects me during the day.


I think I will need to record with pulse ox a few nights at current settings so I have concrete evidence to show my Dr. at follow up. Then I can try to dial in better pressures.

[palerider]

you hurt yourself the most by doing that, it doesn't allow effective thinking. before doing that again, sit back, take 10 slow, deep breaths, calm down, and then think.

I will definitely do that. Thanks again - sometimes I need an outside reminder.

no prob, we all do, from time to time.

as far as I'm aware, the resmed titration guide is right but focused on apnea. if you do some research on bilevel therapy, what you find out is that when using bilevel to treat respiratory distress, you raise epap to increase oxygenation, and you raise ipap to increase co2 blowoff.

that sounds correct. I have read about bi-level therapy. I have a restrictive lung disorder, and in reading about hypoventilation - what happens is that CO2 rises as a result, which then effects oxygenation. this can happen in the absence of obstructive apneas/hypopneas.

eh, not directly. hypoventilation can cause decreased o2 levels (basically whey hypopneas are bad) and increased co2. the rise in co2 normally increases your need to breath, (when you hold your breath, it's not lack of o2 that gives that overwhelming need to gasp for breath, it's too much co2, playing with an oximeter will confirm that).

I suffer from nocturnal sleep-related hypoventilation due to a restrictive chest wall disorder. my cardiologist said this is sleep-related respiratory failure, which of course I would love to resolve as it effects me during the day.

I think I will need to record with pulse ox a few nights at current settings so I have concrete evidence to show my Dr. at follow up. Then I can try to dial in better pressures.

that's a good idea, more data is better. correlate that to your data from the cpap and it's even more informative. but, basically, again, more pressure support, less co2, more ventilation, more epap = more baseline oxygenation.

there's some good training videos by respiratory therapists if you look for bilevel/bipap (they do mention that bipap is a trademark but like xerox, a lot of people use it for generic bilevel/copiers.

[raisedfist]

eh, not directly. hypoventilation can cause decreased o2 levels (basically whey hypopneas are bad) and increased co2. the rise in co2 normally increases your need to breath, (when you hold your breath, it's not lack of o2 that gives that overwhelming need to gasp for breath, it's too much co2, playing with an oximeter will confirm that).

Yeah I am happy the hypopneas are being treated. I was reading some research studies specific to nocturnal ventilation and chest wall disorders, and a few noted that the relationship between CO2 levels and SpO2 values are inextricably linked because we can think of our body as a fixed space made up primarily of the gases CO2, O2 and Nitrogen. In these studies they used SpO2 to indirectly infer whether CO2 was being controlled. Basically, a drop in SpO2 not explained by apnea/hypopnea was because of untreated hypoventilation (for this specific patient population).

that's a good idea, more data is better. correlate that to your data from the cpap and it's even more informative. but, basically, again, more pressure support, less co2, more ventilation, more epap = more baseline oxygenation.

there's some good training videos by respiratory therapists if you look for bilevel/bipap (they do mention that bipap is a trademark but like xerox, a lot of people use it for generic bilevel/copiers.

I will probably increase the IPAP by value of 2.0 and see what happens. I will keep EPAP the same, but if I max out IPAP I would have to lower the EPAP in order to further increase the pressure support. Hopefully that wouldn't be necessary. On the Resmed Aircurve 10 VAuto the lowest EPAP possible is 4.0 - I assume that is so there is adequate mask washout?

[palerider]

I was reading some research studies specific to nocturnal ventilation and chest wall disorders, and a few noted that the relationship between CO2 levels and SpO2 values are inextricably linked because we can think of our body as a fixed space made up primarily of the gases CO2, O2 and Nitrogen. In these studies they used SpO2 to indirectly infer whether CO2 was being controlled. Basically, a drop in SpO2 not explained by apnea/hypopnea was because of untreated hypoventilation (for this specific patient population).

I believe that's an oversimplification. you can be breathing normally and have 98-99% spo2, then hyperventilate yourself to the point of passing out, that doesn't increase your spo2 over 100%, but it does drive your co2 way down, and if spo2 and were inextricably linked, then there'd be no reason to measure co2, or develop tc-co2 monitoring device.

I will probably increase the IPAP by value of 2.0 and see what happens. I will keep EPAP the same, but if I max out IPAP I would have to lower the EPAP in order to further increase the pressure support. Hopefully that wouldn't be necessary. On the Resmed Aircurve 10 VAuto the lowest EPAP possible is 4.0 - I assume that is so there is adequate mask washout?

eh, lowest epap is 3, highest ipap is 25. that's a hellavalotta pressure support, and quite uncomfortable.

[raisedfist]

I believe that's an oversimplification. you can be breathing normally and have 98-99% spo2, then hyperventilate yourself to the point of passing out, that doesn't increase your spo2 over 100%, but it does drive your co2 way down, and if spo2 and were inextricably linked, then there'd be no reason to measure co2, or develop tc-co2 monitoring device.

Only one lab I've been to had end-tidal CO2 monitoring capabilities (a university hospital in Chicago). I've been told by one of my past Sleep Dr.'s that it can be unreliable and inaccurate for bi-level in the lab - but I don't know anything further than that. I assume if calibrated correctly it should be fairly reliable, but that is just a guess.

eh, lowest epap is 3, highest ipap is 25. that's a hellavalotta pressure support, and quite uncomfortable.

I've used a pressure support of 16 before in the past - my first sleep study ever titrated me to 20/4. It was a wild ride. It was tolerable after a while but still not fun. I STILL had desats at home.

[palerider]

Only one lab I've been to had end-tidal CO2 monitoring capabilities (a university hospital in Chicago). I've been told by one of my past Sleep Dr.'s that it can be unreliable and inaccurate for bi-level in the lab - but I don't know anything further than that. I assume if calibrated correctly it should be fairly reliable, but that is just a guess.

there are transcutaneous co2 monitoring devices coming on the market, which don't require blood draw to measure blood co2 levels. here's some more info comparing that to what you had:
http://www.radiometer.com/~/media/radio ... 080114.pdf

I've used a pressure support of 16 before in the past - my first sleep study ever titrated me to 20/4. It was a wild ride. It was tolerable after a while but still not fun. I STILL had desats at home.

wild guess, needed more epap.

[raisedfist]

there are transcutaneous co2 monitoring devices coming on the market, which don't require blood draw to measure blood co2 levels. here's some more info comparing that to what you had:
http://www.radiometer.com/~/media/radio ... 080114.pdf

interesting! thanks for the link. I still have flashbacks to when I had to have ABG draws done as an in-patient, the doctor missed my artery 4-5 times before the nurse finally came and did it on the first try. I was already in a state of distress, obviously, and I was cursing like a sailor while the Doc was apologizing profusely.

wild guess, needed more epap.

yeah I think so lol. perhaps at higher levels of pressure support you can run into a problem of airway patency because of increased airway resistance?

[palerider]

perhaps at higher levels of pressure support you can run into a problem of airway patency because of increased airway resistance?

perhaps, but I'm not aware of such thing.

[raisedfist]

Ramped the IPAP up to 20 last night and dropped the EPAP to 4. No more sustained SpO2 drops. The nasal pillows handle higher pressures much better than my F&P Simplus full face, I didn't feel any leaking or frustration with the mask at all.

Basal SpO2 was 94.2% (good for me, and higher than usual) and time spent below 88% was 6 minutes out of 9.5 hours. Mostly they were desat spikes that went up and down but they were very brief in length - my AHI was 6.4 when usually it is 0.0 - 0.1.

My mouth kept popping open but I wanted to keep recording the data so I dealt with it all night. I STILL feel better - probably from clearing more CO2 and apparently preventing hypoventilation from occurring. All the AHI shows up as "unclassified apneas" in Sleepyhead (0.0 for hypopnea, obstructive, clear airway). There were no large leaks reported.

I am going to increase the EPAP tonight and see what happens. Hopefully it will deal with those events that cause desaturation spikes and make the oxygen saturation steady throughout the night.

[palerider]

My mouth kept popping open but I wanted to keep recording the data so I dealt with it all night. I STILL feel better - probably from clearing more CO2 and apparently preventing hypoventilation from occurring. All the AHI shows up as "unclassified apneas" in Sleepyhead (0.0 for hypopnea, obstructive, clear airway). There were no large leaks reported.

how bad were the leaks?