Does EPR reduce therapy effectiveness?

Really · Post by **Really** » Thu Aug 05, 2010 4:36 pm

billbolton wrote:
Slinky wrote:Most of us end up turning it off, and turning Ramp off too eventually as we get acclimated to and comfortable w/our PAP therapy.
That would be some, not most.

Cheers,

Bill

Thanks for the contribution Bill.

Still not sleeping well? Really

Physician · Post by **Physician** » Thu Aug 05, 2010 6:07 pm

Wulfman wrote:Yes......potentially.
As has been discussed many times before, EPR drops the pressure on exhale in the number of centimeters according to which setting you select......1 drops 1 cm......2 drops 2 cm......3 drops 3 cm.......for the full exhale period. If the user is prone to having apneas at the point of "end-of-exhale"/"beginning-of-inhale", then you either need to reduce the EPR number or compensate for that with a higher set pressure if you're using CPAP mode or higher minimum pressures if you're using APAP mode.

Den

This makes no sense. How does one have apnea with passive expiration ? Partial obstruction, maybe, but not apnea.

dsm · Post by **dsm** » Thu Aug 05, 2010 6:15 pm

Physician wrote:
Wulfman wrote:Yes......potentially.
As has been discussed many times before, EPR drops the pressure on exhale in the number of centimeters according to which setting you select......1 drops 1 cm......2 drops 2 cm......3 drops 3 cm.......for the full exhale period. If the user is prone to having apneas at the point of "end-of-exhale"/"beginning-of-inhale", then you either need to reduce the EPR number or compensate for that with a higher set pressure if you're using CPAP mode or higher minimum pressures if you're using APAP mode.

Den

This makes no sense. How does one have apnea with passive expiration ? Partial obstruction, maybe, but not apnea.

Physician,

The way I have heard this described (RestedGal & SWS I think), is that on exhale for some people (esp when on their back) as they finish the exhale the soft palate 'flops' closed & also, due to the pressure having been lowered 'just enough' (EPR=3), some people then have an apnea at the crossover point of breathing out & then trying to breathe in.

Also, it seems that people who are on a cpap pressure around the 9-11 range, who have EPR set to 3, may also be more prone to 'end expiration apneas'.

I think that covers the explanation

Cheers DSM

Wulfman · Post by **Wulfman** » Thu Aug 05, 2010 6:17 pm

Physician wrote:
Wulfman wrote:Yes......potentially.
As has been discussed many times before, EPR drops the pressure on exhale in the number of centimeters according to which setting you select......1 drops 1 cm......2 drops 2 cm......3 drops 3 cm.......for the full exhale period. If the user is prone to having apneas at the point of "end-of-exhale"/"beginning-of-inhale", then you either need to reduce the EPR number or compensate for that with a higher set pressure if you're using CPAP mode or higher minimum pressures if you're using APAP mode.

Den

This makes no sense. How does one have apnea with passive expiration ? Partial obstruction, maybe, but not apnea.

The problem CAN occur at the END of the expiration cycle when the exhaled air is no longer keeping the airway open and IF the airway should collapse as the person tries to inhale.......IF the person is susceptible to events at that time.

If that makes "no sense", then Bi-level therapy has no validity.

Den

-SWS · Post by **-SWS** » Thu Aug 05, 2010 8:01 pm

Physician wrote: This makes no sense. How does one have apnea with passive expiration ? Partial obstruction, maybe, but not apnea.

Passive expiration refers to elastic recoil. But as Den mentioned upper airway pressure itself begins to wane as that elastic recoil comes to an end AND expiratory volume has been largely expelled. That's when upper airway closure commonly sets in. So inhalation doesn't even have a chance to get started in some of those cases.

But my understanding is THAT'S why standard BiLevel titration protocol dictates that expiratory BiLevel pressure (called EPAP) be used to address obstructive apneas. However, that same BiLevel protocol calls for inspiratory BiLevel pressure (called IPAP) to be used for hypopneas. In that latter case expiration always manages to complete, and inspiration always manages to commence----albeit with undershoot thanks to partial occlusion or even lacking central drive (obstructive versus central hypopneas).

Partial obstruction can also be an apnea rather than hypopnea. Here's an obstructive apnea with 80% flow reduction:

jnk · Post by **jnk** » Thu Aug 05, 2010 8:29 pm

In support of -SWS' point on bilevel titration protocol:

"4.3.2.2 IPAP and EPAP should be increased (according to the criterion in Recommendation 4.3.2.1) if at least 1 obstructive apnea is observed for patients <12 years or if at least 2 obstructive apneas are observed for patients ≥12 years (Consensus).
This recommendation is based on consensus agreement by the PAP Titration Task Force. As in the case of CPAP, a lower pressure is required to treat apneas compared to the pressure required to treat other respiratory events (see Recommendation 4.2.2.2); however, there is 1 level II study and 1 level V study that used increases in both IPAP and EPAP to eliminate apneas.
"4.3.2.3 IPAP should be increased (according to the criterion in Recommendation 4.3.2.1) if at least 1 hypopnea is observed for patients <12 years or if at least 3 hypopneas are observed for patients ≥12 years (Consensus).
This recommendation is based on consensus agreement by the PAP Titration Task Force." -- http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2335396/

"Treatment of obstructive sleep apnea with nasal continuous positive airway pressure mandates simultaneous increases of both inspiratory and expiratory positive airway pressures to eliminate apneas as well as nonapneic oxyhemoglobin desaturation events. We hypothesized that the forces acting to collapse the upper airway during inspiration and expiration are of different magnitudes and that obstructive sleep-disordered breathing events (including apneas, hypopneas and nonapneic desaturation events) could be eliminated at lower levels of EPAP than IPAP. To test these hypotheses, a device was built that allows the independent adjustment of EPAP and IPAP (nasal BiPAP). Our data support the hypotheses that expiratory phase events are important in the pathogenesis of OSA and that there are differences in the magnitudes of the forces destabilizing the upper airway during inspiration and expiration. Finally, applying these concepts, we have shown that by using a device that permits independent adjustment of EPAP and IPAP, obstructive sleep-disordered breathing can be eliminated at lower levels of expiratory airway pressure compared with conventional nasal CPAP therapy. This may reduce the adverse effects associated with nasal CPAP therapy and improve long-term therapeutic compliance." -- http://www.ncbi.nlm.nih.gov/pubmed/2198134

-SWS · Post by **-SWS** » Thu Aug 05, 2010 9:13 pm

Great to see you, jnk.

Also, see page 27 of 36 in this PDF document for a very high-level BiLevel titration protocol description: http://www.n2sleep.com/Portals/408/Skin ... ations.pdf

And an admittedly old article discussing apneas as an 80% to 100% reduction in flow: http://www.sleepreviewmag.com/issues/ar ... -04_07.asp

jmelby · Post by **jmelby** » Fri Aug 06, 2010 7:09 am

The RT in my doctor's office told me that the doctor does not ever prescribe that EPR be turned on or patient-settable because it CAN affect therapy. They only enable it when a patient complains of exhalation problems. I went ahead and tried it myself anyway... and sure enough, I found that my AHI went up significantly for that week. I had even followed Rested Gal's advice of raising my minimum pressure by the same amount (EPR of just 1 was what I tried). So, I don't use EPR... I must be one of those people who are susceptible to apneas on exhalation.

Does EPR reduce therapy effectiveness?

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Makes no sense

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