Respiratory Wave Form correction, Bilevel vs EPR advantages - OSCAR data UK user

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I did do a very brief test with EPR enabled last month.

Actually not. F&P does not have EPR, it has Expiratory Relief. EPR was discovered to share similarities with BiPAP through waveform analysis when it first came out. It was revealed that EPR extends into inspiration which gives it BiPAP quality. IDK if F&P Expiratory Relief behaves in the same manner.

[Egg Yolkeo]

I did do a very brief test with EPR enabled last month.

Actually not. F&P does not have EPR, it has Expiratory Relief. EPR was discovered to share similarities with BiPAP through waveform analysis when it first came out. It was revealed that EPR extends into inspiration which gives it BiPAP quality. IDK if F&P Expiratory Relief behaves in the same manner.

I believe it does, at least when I enable it, OSCAR reports that EPR is enabled and reports level 1, 2 or 3 if I change it.

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I believe it does, at least when I enable it, OSCAR reports that EPR is enabled and reports level 1, 2 or 3 if I change it.

OK but that's not how you determine if F&P Expiratory Relief behaves like ResMed EPR (AAMOF, if it was identical then ResMed would sue for patent infringement).

I can show you some of the process to determine this:

Is EPR Really Bilevel? by sleepydave

When the coming of Expiratory Pressure Relief (EPR) was first announced, I had some questions as to whether this modality would offer relief on active expiration only during the CPAP mode, and perhaps address the issues that other expiratory adjuncts were having, or if the drop in expiratory pressure were carried out all the way to the next inspiration, relying on inspiration as the trigger to terminate EPR, and thus essentially operate in a BiPAP mode.

The following waveform analyses were performed on the EPR mode at 10 cmH2O with an EPR setting of 3 cmH2O. The breath rate is approximately 12.

The first graph shows the breathing waveform on top, inspiration being an upward deflection and expiration downward, while the bottom graph is measuring pressure. The pressure settings are seen as faint numbers at the left of the pressure waveform. You can see that the EPR, reflected as a drop in the therapeutic pressure on the pressure waveform down to about 7 cmH2O, is carried out all the way to the point of inspiration, and the inspiratory effort therefore takes place at a sub-therapeutic pressure. The baseline pressure returns to 10 cmH2O, but not until after inspiration has begun. In other words, inspiration is the trigger to terminate EPR, and instead of a CPAP pressure of 10 cmH2O with an expiratory adjunct, we are effectively left with BiPAP of 10/7:

[Image: epr11.jpg]

This might not make a clinical difference if the patient ends up with the same results on BiPAP 10/7 that he would have on CPAP 10 cmH2O (which could be the case if there were only flow limitations, snores, or hypopneas). But if the new EPR-defined EPAP is below the apnea threshold, then there could be a problem.

In the second graph, the waveforms are superimposed to show more clearly that inspiration is occurring at a sub-therapeutic level:

[Image: epr12.jpg]

There is a time limitation associated with the termination of EPR. In the next graph, you can see how the EPR eventually terminates and returns to baseline. In this instance, the breath rate was approximately 6, so the time to EPR termination was appoximately 5 seconds. The first arrow represents EPR termination, while the second signifies patient breath:

[Image: epr13.jpg]

And here again, the graphs are superimposed to show the return to baseline relative to inspiration:

[Image: epr14.jpg]

This means that eventually, there will be a return to baseline CPAP if in fact, an apnea occurs, and at the most, only one breath would be missed. Is the net result clinically relevant? I'm not sure either way. But if you're generating negative intrathoracic pressure or creating arousals, then there could be an issue.

In re: putting EPR in the AutoSet mode, that could be an effective way to overcome this supposed shortcoming of EPR. If events were to start occurring at, in this case, "10 cmH2O of CPAP". then baseline pressure could be raised, theoretically, to "13 cmH2O of CPAP", or effectively BiPAP 13/10. Course now we're right back where we started. The only outstanding question would be if the 13/10 format was better tolerated than the straight 10.

But how would the algorithm work? If the apnea identification in AutoCPAP is 10 seconds, and the EPR terminates at (in this case) 6 seconds, how would it know to increase the CPAP (really the "EPAP" segment of EPR) to address apneas? I would assume that flow limitations would be properly addressed with CPAP increase (because you're really raising the "IPAP" segment of EPR).

As an aside, therein lies the problem once you start talking about Auto-BiPAP. Do you increase the IPAP, and keep EPAP fixed, or do you vary the EPAP as well, looking to address apneas. You're gonna need two totally separate algorithms, and they can't interfere with each other.

There are a couple of options available with EPR. It can be used during the ramp period only, which would offer significant patient comfort during a time where the perhaps the greatest period of patient difficulty occurs. After the ramp period is over, it returns to the set pressure.

Before you select full-time EPR, though, and carry EPR throughout the night, you should consider how your particular situation might respond to this modality. And I think the key to EPR, AutoCPAP with EPR (should that ever come about) and AutoBiPAP will be how apneas are addressed. You might be OK dealing with hypopneas, snores and RERAs if you're of the belief that BiPAP can properly address these issues. And that's a whole 'nother discussion

as offered by the brilliant poster sleepydave in 2005, but since the image links are broken it's not really clear (and I believe those images are gone forever).

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I believe F&P Expiratory Relief behaves more like Respironics CFlex, but we'd have to dig a little more.

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Or just DW and see what happens.

[Egg Yolkeo]

There is no AHI problem, it's all about trying to improve the inspiratory waveform.

It appears whatever that is is not particularly pressure-responsive as there is some marginally good stuff at any pressure. And bad stuff at any pressure. Perhaps body position, neck position and/or sleep stage has influence on waveform.

BiPAP, with some fiddlement of Advanced Settings like I:Time, is definitely worth a shot to improve that inspiratory waveform rather than jacking that pressure any higher.

I wanted to post some an update with some additional information

Summary of the ENT report:
Neck shows no lumps or lymphadenopathy, his throat was normal looking. Flexible endoscopic examination of larynx and pharynx demonstrated no lumps or lesions.

He will be seeing a respiratory therapist next week to assess his breathing.

We have a trial Lumis 150 VPAP ST-A. I initially tried using S mode but with very limited success as it was like he was fighting with the machine, so changed to iVAPS mode and used learn Targets and Auto EPAP. I did a couple of short trials on on its default settings and one with lower EPAP and PS just to get a view of what the waveforms looked like vs his CPAP.

The first short session is shown below
I didnt change the EPAP,IPAP or PS settings, they were on the max range.
TiMax It was either 2.0 or 1.5s
TiMin 0.8
Trigger Very High
Cycle Low
Rise time 500ms

First observation was that there was a significant improvement in his respiratory waveforms and the mid inspiration dips below the zero line were reduced drastically.

I also noted the tidal volume fluctuated a lot on the higher pressures. His Med on CPAP is about 360 and 95% is about 600.

iVAPS session 1.png (192.51 KiB) Viewed 3294 times

iVAPS session 1 closeup.png (164.32 KiB) Viewed 3294 times

iVAPS session 1 closeup 2.png (163.08 KiB) Viewed 3294 times

[Egg Yolkeo]

Last screenshot from first short session.

iVAPS session 1 4.png (165.29 KiB) Viewed 3294 times

[Egg Yolkeo]

I then did a second short session with lower pressure settings as follows to see what the waveform would do

iVAPS

Target PT 22
Target VA 7.9L

Auto EPAP Yes
Min EPAP 5
Max EPAP 9
Min PS 4
Max PS 8
TiMax 1.5
TiMin 0.8
Trigger Very High
Cycle Low

As far as I could see at the lower pressures the ridged top of the waveform seems to become more prevalent, but the mid inspiration drops below the zero line were still effectively eliminated compared to his CPAP.

iVAPS session 2.png (187.35 KiB) Viewed 3293 times

iVAPS session 2 pt 2.png (180 KiB) Viewed 3293 times

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Whose idea was it to use iVAPS?

Who decided settings?

Did he sleep at all during this trial?

I think rate, tidal volume and minute ventilation are too high.

Need new endoscopic exam, complete PFT, overnight oximetry and perhaps ABG.

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What's his height, weight and age?

Do you have any oximetry data?

iVAPS is designed to treat respiratory failure. Does he have that?

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He will be seeing a respiratory therapist next week to assess his breathing.

Does he have the authority to order and/or perform the above testing?

[Egg Yolkeo]

Whose idea was it to use iVAPS?

Who decided settings?

Did he sleep at all during this trial?

I think rate, tidal volume and minute ventilation are too high.

Need new endoscopic exam, complete PFT, overnight oximetry and perhaps ABG.

The intention was to use Bilevel S mode not IVAPS. However as his respiratory waveform is both abnormal when he is awake or when he is asleep, I wanted to a do a short day time test and see what the modes would look like in OSCAR and compare them to his CPAP waveform.

I applied the Resmed and NHS settings for restricted breathing/scoliosis. I ran the learn targets and enabled Auto EPAP and then tried to set the unit so to match his CPAP pressure ranges.

He did briefly sleep in the first test on S mode where he had some events and then again later on the first Ivaps test where he had one event.

[Egg Yolkeo]

What's his height, weight and age?

Do you have any oximetry data?

iVAPS is designed to treat respiratory failure. Does he have that?

He will be seeing a respiratory therapist next week to assess his breathing.

Does he have the authority to order and/or perform the above testing?

He is 73, 80kg and 5 Ft 8 Inches/172cm - although he has shrunk and used to be 5 ft 10/177cm

I dont have oximetry data but I will be getting an O2 ring.

As I understood Resmed consider Scoliosis a restrictive lung disease which iVAPS can be used for. WIth that said I wanted to use the machine on Bilevel S Mode and will be trying that mode again and trying to get that working comfortably.

This is the first meeting so I will be finding out what can and cant be done.

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As I understood Resmed consider Scoliosis a restrictive lung disease which iVAPS can be used for.

Scoliosis may cause restrictive lung disease. You can't tell what the degree of restriction and/or obstruction is w/o a PFT (and in some cases, ABG).

Specifically, ResMed states:

iVAPS is suitable for adults with respiratory insufficiency

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ResMed's criteria (although it's based on RAD Criteria from The Colonies):

Either ABG with PaCO2 ≥ 45 mmHg OR SaO2 ≤ 88% for ≥ 5 minutes for at least 2 hours nocturnal recording time OR FVC < 50% of predicted or MIP < 60 cmH2O (NMD only).