Squishing the belly increases AHI

[Muffy]

I just got back home from attending our nation's major sporting grand final. The good thing with this game, is players smash into each other without any... helmets...

Thanks very much for sharing that.

It explains a lot.

Muffy

Yeah, it shows how tough us Aussies are. No prancing around acting all tough yet wearing full body protection.

OK, we'll go with that.

So you increased hypopneas by 50%. How about their length and corresponding desats (or did you use the 4b "arousal" criteria)? Why isn't there a greater shift towards apneas (or do you have a relative measure of flow pre/post that shows increased restriction)?

My understanding of "arousal threshold" is "screwing up their sleep with a giant cuff".

What's the chance of posting an *.edf of the pre- post- EEG?

With all that "playing football without a helmet", keep alert for any change in neuro signs.

Muffy

Muffy

[Muffy]

Some of you would be aware of my work in this thread viewtopic.php?f=1&t=19370&st=0&sk=t&sd= ... beer+belly In this study, I showed that compressing the abdomen, made the airway more collapsible.

Did Steier ever write back?

Yeah he did. I thought you were going to follow it up with him though?

No. I specifically said I wasn't.

And his answer....

Yes, I agree - cardiac contraction is clearly responsible for a few cmH2O pressure change - we have manually selected the analysed bits outside any artefactual pressure deflections, taking the baseline from endexpiratory pressures.

Well in his published data (the graphic that's supposed to support his whole concept)(which should have been "cherry-picked" to demonstrate a "no-question-this is-what-happens-here"), the supine Pes clearly does not "analyse... outside any artefactual pressure deflections".

There's also breath-to-breath variability that shows that's really the only breath that has iPEEP.

Arguably, I would have put start of inspiration a little to the left (at the beginning of EMGdi/Pdi) rather than where he has it (flow = 0) and dismissed than little downward deflection as the air-trapping component. That would make iPEEP = 0.

OTTO, in the big scheme of things, I don't imagine that it makes a BFD.

Chiliaphobes, unite!

Muffy

[split_city]

So you increased hypopneas by 50%. How about their length and corresponding desats (or did you use the 4b "arousal" criteria)? Why isn't there a greater shift towards apneas (or do you have a relative measure of flow pre/post that shows increased restriction)?

I have only completed analyzing 10/14 patients. However, it looks like event length (all types of events) is not different between conditions (~21.3, ~21.5 and ~22.8 secs for deflated, mid and inflated). If, as you pointed out earlier, abdominal compression pushed patients closer to their arousal threshold, then one might hypothesize that event length may decrease with abdominal loading.

The average desat for each condition (deflated, mid and max) so far is ~3.2, ~2.7 and ~2.7%

Our lab's definition of a hypopnea is a ≥10 sec event defined by either a) >50% decrease in flow compared to the previous 2 mins of breathing or b) a discernable decrease in effort followed by an arousal or a ≥3% desaturation.

I'm not sure why there wasn't a greater shift from hypopneas to apneas. We certainly did have several patients who were diagnosed with mild OSA, so their hypopneas weren't "severe" to begin with. It might also be good to look at whether the hypopnea "severity" (average breath x breath minute ventilaion or PIF) changed with abdominal loading (as discussed by you).

[NotMuffy]

The average desat for each condition (deflated, mid and max) so far is ~3.2, ~2.7 and ~2.7%

Our lab's definition of a hypopnea is a ≥10 sec event defined by either a) >50% decrease in flow compared to the previous 2 mins of breathing or b) a discernable decrease in effort followed by an arousal or a ≥3% desaturation.

Thank God for 4b.

It might also be good to look at whether the hypopnea "severity" (average breath x breath minute ventilaion or PIF)...

If you're talking minute ventialotion, are you scoring your hypopneas off a pneumotach?

Can you put your flow/effort channels in the *.edf?

[NotMuffy]

And his answer....

Yes, I agree - cardiac contraction is clearly responsible for a few cmH2O pressure change - we have manually selected the analysed bits outside any artefactual pressure deflections, taking the baseline from endexpiratory pressures.

Well in his published data (the graphic that's supposed to support his whole concept)(which should have been "cherry-picked" to demonstrate a "no-question-this is-what-happens-here"), the supine Pes clearly does not "analyse... outside any artefactual pressure deflections".

There's also breath-to-breath variability that shows that's really the only breath that has iPEEP.

Arguably, I would have put start of inspiration a little to the left (at the beginning of EMGdi/Pdi) rather than where he has it (flow = 0) and dismissed than little downward deflection as the air-trapping component. That would make iPEEP = 0.

You mean like this (although as noted, it seems like each breath needs to be analyzed separately for determination of "baseline"):



Perhaps the worldly calist can give us his thoughts on ballistocardiographic contamination of pressure signals.

[split_city]

It might also be good to look at whether the hypopnea "severity" (average breath x breath minute ventilaion or PIF)...

If you're talking minute ventialotion, are you scoring your hypopneas off a pneumotach?

Yes I did use a pneumotach.

Can you put your flow/effort channels in the *.edf?

Do you want flow/effort data in addition to EEG? Not sure if possible given that I have recorded EEG on a separate computer. What sort of time scale you after?

[NotMuffy]

Do you want flow/effort data in addition to EEG? Not sure if possible given that I have recorded EEG on a separate computer. What sort of time scale you after?

If you can convert them to *.edf, I can put them together with a generic EDF Reader.

[split_city]

Do you want flow/effort data in addition to EEG? Not sure if possible given that I have recorded EEG on a separate computer. What sort of time scale you after?

If you can convert them to *.edf, I can put them together with a generic EDF Reader.

Any advice on how to convert them? All ventilatory and pressure data were acquired using Windaq while EEG stuff was acquired using NetBeacon/PSG Online 2 but can be viewed using ProFusion.

[NotMuffy]

Any advice on how to convert them? All ventilatory and pressure data were acquired using Windaq while EEG stuff was acquired using NetBeacon/PSG Online 2 but can be viewed using ProFusion.

Profusion converts to *.edf in Tools. I got Windaq. What acquisition box are you using?

[split_city]

Any advice on how to convert them? All ventilatory and pressure data were acquired using Windaq while EEG stuff was acquired using NetBeacon/PSG Online 2 but can be viewed using ProFusion.

Profusion converts to *.edf in Tools. I got Windaq. What acquisition box are you using?

I'll have a go at converting a file to *.edf tomorrow (now is sleep time after nightshift).

Well, we had been using a DI-720 but our lab had a direct hit from a lightning bolt a few weeks back, knocking out few bits of equipment. Our unit is getting repaired at the moment so we are using our older backup model.

[NotMuffy]

...now is sleep time after nightshift...

Let's Go!!

I'll have a go at converting a file to *.edf tomorrow

OK cool, maybe in the meanwhile you can throw up some paired *.wdqs.

You weren't by any chance measuring CO2s (ET or Tc), were you?

[split_city]

I'll have a go at converting a file to *.edf tomorrow

Looks like this will have to wait until my next nightshift as I didn't realise my home laptop only had the lite version of ProFusion, meaning I can't export an EDF file.

OK cool, maybe in the meanwhile you can throw up some paired *.wdqs.

Sure. What do you want me to show? What sort of time scale do you want? I just realised that I did split EEG data into our Windaq box as well.

You weren't by any chance measuring CO2s (ET or Tc), were you?

Yes I also measured ETCO2.

[NotMuffy]

OK cool, maybe in the meanwhile you can throw up some paired *.wdqs.

Sure. What do you want me to show?

I need the entire file. Any file sharing service will do.

I have to "feel" the patient.

[split_city]

OK cool, maybe in the meanwhile you can throw up some paired *.wdqs.

Sure. What do you want me to show?

I need the entire file. Any file sharing service will do.

I have to "feel" the patient.

Windaq files are 200-300MB. Are you ok with this? I might be able to compress them down a bit.

[NotMuffy]

Windaq files are 200-300MB. Are you ok with this?

Sure.

I'm a lot stronger than I look.