Bi-Level Data Question ???

[Slinky]

With IPAP set at 13, EPAP at 8 and Pressure Support at 4 the Maximum pressure reported is 11 cms.

With IPAP at 12 and EPAP at 7, Pressure Support at 4 the maximum pressure reported is 10 cms

With IPAP at 13 and EPAP at 7, Pressure Support at 4 the maximum pressure reported is 11

With IPAP at 12 and EPAP at 8, Pressure Support at 4 the maximumm pressure reported is 10

Does this make any sense to you?

[jnk]

You knew I'd answer, didn't you? Sorry. Maybe one day you'll get your answer better-put from someone more authoritative!

Your machine delivers two pressures linked in tandem all night, since it is an auto bilevel. BUT, it only has the ability to report to you ONE number as your 95th centile pressure for the night. So, instead of reporting to you your experienced ipap pressure or reporting to you your experienced epap pressure, it is giving you a made-up number exactly in the middle of those two numbers.

Note that in the examples you give, your reported "pressure" is always exactly 2 less than what you had maximum ipap set at that night. That means your machine was staying at the ceiling you had set for it, in view of your pressure support being set at 4.

Here is the formula the manual gives:

"Note that the actual delivered pressures will be +/- 0.5 x pressure support (as set by the clinician)."

In other words add one half of your pressure support number to the reported "pressure" to find out your real ipap number and subtract one half of your pressure support number to the reported "pressure" to find our your real epap number.

Let's take your first example. [Max ipap at 13 and min epap at 8 and pressure support at 4.] The number reported to you in the morning was 11. So, add two to get your experienced 95th centile ipap pressure (13) and subtract two to get your experienced 95th centile epap pressure (9). The machine gave you the "11" so you could figure out that your real numbers were 13/9.

You gave your machine one cm to work with up or down (the 4 cm gap only had one cm wiggle room since you only gave it 5 cm distance to work in), so your numbers mean that for most of the night your machine's output stayed maxed out at the highest it could go beneath the ceiling that you gave it.

[Slinky]

Okay. BUT I wasn't going by the reported Median, 95th Percentile and Maxium pressures I was going by the software graphs.

So, if the Statistics reported Median, 95th Percentile AND Maximum pressures are all at 10 cms AND the bar graph shows the Median pressure at 10 and won't go any higher then I need to do what?

Up the IPAP setting?
Widen the Pressure Support?

[jnk]

I don't use the software. Wish I did.

Raising the maximum ipap number would be the way to allow the machine to put out more pressure, if that's really what you want to happen and know it's OK for that to happen. But, as I understand it, someone with COPD may be using the bilevel a little differently from, and for a slightly different reason from, the way an OSA-only patient might. I would think your doctors would be more interested in volume of air moved, which would, I believe, be affected by the pressure support number you/he/she/they choose, since a bipap is a lot like a ventilator. It all depends on what you/they are trying to accomplish, and that is way beyond the scope of my very limited understanding of anything medical.

It's like Snoredog said, if he doesn't mind my quoting him, there are specific protocols for titrating COPD patients.

I play with my numbers on my auto just for fun. But, frankly, I cringe a little to think about you changing yours.

I only say that because I care--even though, of course, it's not really any of my business.

jnk

[Slinky]

Doctor is satisfied w/things as is. I'm not.

I'm considering IPAP 14, EPAP 7, even tho that is a pretty big gap.

OR IPAP 13, EPAP 7 and Pressure Support 5.

I've got 3 more nights of data to collect before making any decisions.

I don't need a darn sleep doctor! I need a good RPSGT to just explan a few things. Mumble, grumble. The RPSGT most likely understands the data better anyway. I don't think these sleep doctors have ANY understanding of the finer points of fine tuning xPAP therapy anyay. Certainly not like a good RPSGT would!

[jnk]

From a report from about 18 years ago

As starting points, an IPAP of 8 mm Hg and an EPAP of 4 mm Hg are generally used. Protocols should be used to adjust the pressure. For example, IPAP should be increased to improve alveolar ventilation or Paco2, and EPAP should be increased to improve oxygenation and/or obstructive sleep apnea. It is important to remember that if the EPAP is increased, the practitioner must also increase the IPAP to maintain the same pressure difference. The minimum EPAP level recommended by most manufacturers is 4 mm Hg. If supplemental oxygen is needed, it can be supplied through the NPPV system. Most manufacturers publish a bleed-in chart for oxygen to help the practitioner maintain the patient’s ordered flow rate or fraction of inspired oxygen.

Patients should be monitored on a regular basis. Monitoring should include the parameters that were used for patient selection; in addition, patients should be monitored for symptom relief, levels of daytime activity, signs of cor pulmonale, pedal edema, and respiratory rate. In most cases, the practitioner should see improvements in the patient’s resting respiratory rate, oxygen saturation, level of activity, decreased Paco2, and fewer hospital admissions.

Conclusion

. . . Even small improvements may lead to significant functional benefits, improving the quality of life. . . . Nocturnal bilevel NPPV can create significant improvements in function, activities of daily living, and quality of life.

[jnk]

Here is an explanation of why volume of air moved is important for COPD patients, and thus the importance of the pressure support chosen:

http://www.talkaboutsleep.com/sleep-dis ... APchat.htm

someone with chronic obstructive pulmonary disease (COPD), due to damage to both airways and lung air sacs, has a very difficult time ventilating (moving a sufficient volume of air in and out of the vast lung fields to "blow off" enough CO2 to normal levels). If they work harder to ventilate, they produce more CO2; it becomes a vicious cycle. A bilevel device is a ventilator that augments your spontaneous effort to help blow off CO2 by increasing the volume of air per breath without you increasing effort. In fact, depending on the settings, you may not have to work nearly as hard to maintain as without the therapy. It was once thought that using a bilevel machine would improve CO2 at night when the bilevel device would improve rest by reducing the ventilatory effort of the patient, but they would probably worsen during the day. Since those early days of speculation, it has been well documented that nocturnal ventilation, which can normalize CO2 during the treatment, has a sustaining effect of reducing CO2 during the day as well. The physiology is very complicated, but suffice to say that the body's threshold for CO2 is reset to a lower level. Therefore, the body is no longer targeting the higher CO2 level it had before treatment. The fact that the patient gets a better night's sleep likely helps them maintain more consistent ventilation during the day. The increased breath volume may also help to improve ventilation in areas of the lungs that tend to collapse and improve lung secretion mobilization. Oftentimes, the result is increased quality of life and increased activities of daily living due to higher energy levels.

I added the bold for emphasis.

[Slinky]

Thanks yet again, jnk. You will notice that it keeps referring to close monitoring. Snort! If six month is close monitoring BEFORE we've established satisfactory .... hell's bells not one person ON STAFF at this sleep lab is the LEAST BIT INTERESTED in the leak rate!

As of the last ABG and PFT I'm still not considered a CO2 retainer. I don't think that means tho that I don't retain more CO2 than the "average bear". And yeah, this sleep doc I've been seeing is a pulmonologist. Well, a SLEEP pulmo.

[Banned]

OR IPAP 13, EPAP 7 and Pressure Support 5.

Hi Slinky,

I don't have COPD, but I use 6cmH2O between EEP and MinPS (IPAP) and I get a great nights sleep. It's the maximum spread provided on the Adapt SV. It makes the Adapt SV feel like a respirator. Once you get used to it, it is delightful! I recently got ResScan v3.5 thanks to your lead. Most nights I'm at 0 AHI. On very rare occasions I may spike between .2 to 1.0. Not bad for a guy who self-diagnosed, ordered his own machine, and self-titrated. Thanks for your help with the SW!

Banned

[Slinky]

Congratulations, Banned! Hey, YOU are the one who read thru the advice here and picked up the tips that worked for you!!

I've had my share of 0.0 AIs and plenty of AHIs 5.0 or less. BUT not near what I should have. And yup, I feel one h*ll of a whole lot better since starting CPAP and even a noticeable improvement w/the bi-level. But the fact of the matter is, there are still too many high leaks, too many high AHIs and even on more occasions than shoud be the case too many high AIs. I'm still a case study in .....d*mn, my vocabulary is SHOT! I can't think of the term I want ...... grrrrrrr.

[Snoredog]

With IPAP set at 13, EPAP at 8 and Pressure Support at 4 the Maximum pressure reported is 11 cms.

With IPAP at 12 and EPAP at 7, Pressure Support at 4 the maximum pressure reported is 10 cms

With IPAP at 13 and EPAP at 7, Pressure Support at 4 the maximum pressure reported is 11

With IPAP at 12 and EPAP at 8, Pressure Support at 4 the maximumm pressure reported is 10

Does this make any sense to you?

yep, it appears that must be IPAP "Maximum" and Pressure Support sets the starting IPAP based upon the EPAP "Minimum" setting.

So when you turn on the machine, EPAP will go to what you set the EPAP pressure for, then IPAP will be that pressure plus the Pressure Support value.

This differs from the Respironics version as it doesn't appear to have a built-in "Minimum" Pressure Support (Remstars is hard-coded at 2 cm).

or does it have a built-in "minimum" Pressure Support?

Where does it go with pressure when you turn on the machine? are both pressures the same or is IPAP higher than EPAP? If so how much?

[AdvansCPAP.com]

Hello,

I can see what you're trying to do and couldn't say much about it since it would be just guessing.

But I do have this to say. Honestly, I do not know any knowledgeable accredited sleep Dr. who will use Auto BIPAPs with Data logging to try and correct your sleep apnea. It's just a shot in the dark. The approach can be better handled in a accredited sleep lab with a experienced RPSGT tech doing your sleep study in a controlled environment.

With a good tech, they will watch exactly what is happening during the night with your sleep and how your body responds to different pressures via CPAP, BIPAP, or CFLEX..etc during a proper titration.The tech can see mouth leaks, lip leaks, mask leaks, spontaneous arousals, PLMS (periodic leg movements), EEG arousals..etc. The data your machine is collecting is not detailed enough to tell anyone professional what is really going on with your apnea if you're not still sleeping well. The machine can only operate at certain parameter programmed into it. There is no way one setting on a machine can correct all apnea because everyone’s apnea is different and it a case by case analysis.

Good Dr's and Techs never trust Auto's and especially the data that comes off of them. I've seen many patients who think they’re sleeping well on their unit to then later find out in the lab..its really terrible.

If you're open to some advice, save yourself more headaches by trying to figure out this yourself and go to a accredited lab with an experienced licensed tech. You will be taken care of in one night and no more headaches.

http://www.AdvansCPAP.com

[Slinky]

Thanks, Advans. This is an accredited sleep lab and the sleep pulmo is an accredited sleep doctor and I did have an in-lab bi-level titration and I even used my own mask. They didn't even ask for any of my data when I went in for my 3 month follow up after starting bi-level but I brought a printout anyway.

How are you doing?
Yes, bi-level is helping.
Good. I'd like to see you again in six months.
Well, because of the high leaks which I KNOW are caused by the lip flutters I'm thinking of changing 8 EPAP to 7 and leaving IPAP at 13 or should I drop it to 12?
Well, there shouldn't be any harm in doing so.
I'm also thinking that if I'm doing good there's no sense in coming back in at 6 months for a well-visit. I'm not bashful about calling for help if I'm not doing good as you have found out so what do you say we leave it at I'll see you in one year UNLESS I run into problems and if I do "I" will call "you.
Okay, that's fine. Just be sure to call if you need help.
You can keep that data prinout if you would like.
What? Oh yes, thank you I'll keep it in your file.

So tell me, Advans, if the data from the autoPAPs are unreliable and an in-lab titration didn't quite hit the mark, how many more in-lab titrations at what intervals until we do get it right?

We have yet to find a full face mask small enough to fit comfortably and leak free. A chin strap is useless for the lip flutters.

My most comfortable, effective mask is the old Respironics Simplicity Petite simple nasal cushion mask followed by the new Resmed Mirage Micro Small nasal cushion.

How much difference in size is there with a Pediatric full face mask from the various small adult full face masks?

[Slinky]

By the way, jnk, I appreciate all the trouble you've gone thru to get the Pressure Support thru my thick skull. I figured Pressure Support of 4 meant what seems obvious - 4 cms difference between IPAP and EPAP and the IPAP/EPAP range of 5 allowed for 1 cm leak compensation. I didn't expect the range to be restricted to 3 instead!

I haven't had any inclination to change the Trigger or Cycle Sensitivity from Med to High or Low - yet.

I think I'm pretty much in the right IPAP/EPAP range at 13-7. So I'll work w/the Pressure Support option a week at a time until I've been thru them all or get the leak rate as low as I can w/the pressure needed. Dropping from the titrated 13/8 to 12/7 or 13/7 are giving the better leak, AHI and AI readings. I'm running outta steam in the early evening and getting my second wind in the mid evening instead of early and late afternoon so there's definitely improvement there too. But I need to fill out the week's data w/another 3 nights to be sure about the 13/7.

When I give up and go to Mayo for the Crohn's surgery I might try to see if any of the Mayo sleep docs are actually willing and able to discuss the situation and maybe they will even have some Pediatric full face masks I can try. Maybe. As much faith as I have in Mayo - I'm not sure that it extends to any sleep doctor anymore, even theirs.

[jnk]

Slinky,

I really respect the way you are thinking and involving yourself in your therapy. I agree that you can't trust any doc more than you trust yourself. And I agree that what you need most is a great tech who understands your exact needs AND that machine.

I think you once said that you were thinking of going to S mode, regular bilevel, using your VPAP Auto. I think if I were in your shoes, I might seriously consider doing just that, for several reasons.

For one thing, EasyBreathe is a nice comfort feature, but it moves less air, since it has such a gradual rise up to ipap pressure. And even if you don't retain CO2 badly, you might still feel better letting the machine move more air, so you don't have to, ya know?

So I think I would put the thing in S mode, set the epap the lowest I was comfortable with, set the ipap 4 above epap for a week, then set ipap 5 above epap for a week, then set ipap 6 above epap for a week, and compare how I felt independant of AHI or AI, just based on the distance between ipap and epap. Once I figured out how much distance I could tolerate and how I felt getting more volume in and out of my lungs, THEN I would start looking at AHI and AI and start raising my epap and ipap, if needed, but always keeping them the same distance apart based on my earlier experiment.

Maybe that would be a silly approach. Maybe some techs could comment on how silly that would be, I don't know. But it would be an approach that would work in my mind for me personally, if I were in what I understand to be your shoes. That's just my looopy opinion.

And as I've said before, my opinion and $5 will barely get you a cup o joe at starbucks.

I still cringe to think of a COPD patient playing with pressures. But I respect it.

jnk