BIPAP AUTO-SV SETTINGS HELP

CROWPAT wrote:with rise at 5

Try using AUTO BPM while you experimenting with changes in pressure settings. Don't forget you are also going to want to try a night on 11/15 and 12/16 so you might want your spread sheet.

Crowpat

One thing you may need to take into account when looking at the reported AHI numbers is that the Bipap AutoSV appears to report these numbers incorrectly when the actual scores are very low.

i.e. If my machine scores 2 AI events for the entire night and 1 HI event for the entire night it will show up as an AHI score of 2.0 when in fact it was only 3 events for the entire night which in reality is a score of 3/8 = AHI 0.37 (three events divided by hrs of sleep).

So there is the possibility you are chasing rainbows to get your score below 2.0 if you are barely scoring any events at all.

DSM

Banned, have you found this happening with your machine ? - also how does the AVAPS machine score (does it exhibit the same problem ?)

#2 Just to clarify, Assuming 8 hrs sleep
- if 1 AI event gets recorded the AI score will show as 1.0. If 8 AI events get recorded it still shows as 1.0
- if 1 HI event gets recorded the HI score will show as 1.0. If 8 HI events get recorded it still shows as 1.0
- From the above If 1 AI & 1 HI event were detected for the entire night then the AHI would show as 2.0

Thanks for the additional input. I saw that anomaly early on with Encore Viewer. I still use the numbers it creaes, but know that the "real" numbers are normally much lower than those reported. Have the machine set for 11/15, auto, and rise 3 for tonight. I will report back with results tomorrow.

CROWPAT wrote:Thanks for the additional input. I saw that anomaly early on with Encore Viewer. I still use the numbers it creaes, but know that the "real" numbers are normally much lower than those reported. Have the machine set for 11/15, auto, and rise 3 for tonight. I will report back with results tomorrow.

Crowpat

Good luck & I hope you can get this machine tuned well.

DSM

dsm,

I have taken the numbers for AVAPS and the SV at face-value, but you maybe right.
In any event, I always got 0 AHi out of both machines.

Banned

Here is the same link, but with just last night on it.
Slept OK, but not great. Numbers back to near normal, but felt I was getting too much air and tidal volume wasn't up like I expected it to be.
http://www.afsashoot.com/PAT1.html

Thanks for posting your charts. I've been following this thread. I was diagnosed with Cheyne-Stokes respirations 6 months ago.

My charts often look very similar to this one. My questions for the gurus are in regards to Periodic Breathing events:

1) Why does a PB event happen and the pressures stay toward the low end of the IPAP settings? Why doesn't the IPAP move closer to IPAP max in order to combat the PB event?
2) When I see that pressure made it to IPAP max for a time and no events were recorded, does this mean that the machine bumped IPAP and succesfully prevented an event, whether apnea or PB?

Many thanks,
Tony

CROWPAT wrote:I never tried setting Ipap min to Ipap avg as that would have yielded a pressure far above what I have found workable for me, nor did I try the other. There is no question that I have centrals when Ipap or Epap is above 14 or so.

CROWPAT, a detailed comment from me later in this thread about your above observation---but in relation to how/why the BiPAP autoSV endeavors to fix it with more pressure of all things...


______________________________________________________________________________________________________________________________________

tonycog wrote: Why does a PB event happen and the pressures stay toward the low end of the IPAP settings? Why doesn't the IPAP move closer to IPAP max in order to combat the PB event?

PB is unregulated or poorly controlled oscillation in human breathing. In other words, PB is a sequence of both biological overshoot and biological undershoot regarding too-deep breaths paired with too-shallow breaths. It's a failure in biology to get a good fix or lock on an appropriate volume of air to breathe in---breath after breath.

Once in a state of PB, the algorithm can do nothing to counteract any one breath that happens to entail biological overshoot (inhale breaths that are too big). But you'll notice from the bottom graph below, that IPAP peak actually does move toward IPAP max on those human breaths that are too small (biological undershoot).


Thus the PB episode is shortened by the algorithm being able to at least correct all breaths entailing biological undershoot. The resolution or granularity of your graphs are not fine enough to clearly reflect those few-second-long IPAP peak upswings in the midst of shorter PB episodes. However, that coarse graphical resolution can reflect what you describe in your next question below:

tonycog wrote: When I see that pressure made it to IPAP max for a time and no events were recorded, does this mean that the machine bumped IPAP and succesfully prevented an event, whether apnea or PB?

That's the hope. When you see IPAP max for an extended period of time, you see very many breaths in which your inhalations got out of the starting gate "slow or with initially low-flow" so to speak. The algorithm thus took corrective action on each of those slow-developing breaths---because the algorithm projected that each breath would not meet target flow without correction by a higher IPAP peak.

SWS wrote: That's, in part, why the Respironics and even Resmed SV titration protocols have the clinicians attempt to address the complete obstructive component first---in the Respironics case, preferably with either CPAP (EPAP = IPAP_min) or with a minimally disruptive pair of BiLevel pressures (EPAP < IPAP_min).

I've got to learn to read these protocols.

CROWPAT wrote: My original CPAP setting was 13.

That would appear to be the minimum (EPAP) setting to address your obstructive component.

CrowPat,

Back to basics. SWS is correct. My illogical dial-wingin is getting us nowhere.
For tonight you will need to configure your SV in CPAP mode (EPAP = IPAP_min). The SV function will still work to address any centrals.

Here are your settings for tonight:

EPAP: 13cmH2O
IPAP Min: 13cmH2O
IPAP Max: Unchanged
BPM: Auto
RT: 3

Give us the report in the morning.

Banned

Muffy

Muffy wrote: Muffy

Hey,

This sleep medicine is science! LOL!!

Banned

Muffy

It is easy to poke fun etc: at the less medically trained among us here. My challenge to you is to show you are mature enough to participate the way SWS does. SWS has established an almost unblemished reputation for seeking to explain complex information even when pushed hard by some of us.

Banned my be a modern 'quick draw McGraw' but he has a heart of gold. His intentions are repeatedly good and well meaning. He is also open to reason and persuasion.

I believe you are a very competent clinician and have so much good information to share but it isn't easy to do so without some humility. SWS has proven that repeatedly. If any of us choose to swat those (who otherwise mean well) because they aren't as expert. We all lose out.

Banned has some very useful information based on his observations of what happens when he uses his various machines. You IIRC Muffy, have never used a cpap machine. So I would suggest that whilst to be a good clinician you don't exactly have to use cpaps, you can be humble enough to learn something from those that do.

Optimistically

DSM

dsm wrote:My challenge to you is to show you are mature enough...

How's this for mature?

Go



yourself.

Muffy

dsm wrote: Optimistically
DSM

Hi dsm,

I think all this is Muffy's way to say she approves of CROWPAT's new settings for tonight.
Sometimes she just has a hard time expressing herself. Or relieving herself?

Banned

That phrase Muffy used---"Go silverplate yourself"----is an invitation for friendship!


That idiomatic expression about silverplating originates in these lyrics:


Make new friends,
but keep the old.
One is silver,
and the other is gold...

Precious... those new and old friendships are!