No luck with auto settings-what went wrong?

[old dude]

In an effort to reduce large leaks, I talked my doc into changing my BiPAP pressures to automatic from a straight BiLevel 17/13.

I didn't have much luck and this was with the DME applying the settings per my doc's Rx. They changed the auto Rx to Min EPAP 5, Max IPAP 25 with PS from 2-8. Problem is, the pressures would never get high enough to work effectively. The EPAP stayed pegged at 5 no matter what and the IPAP would never get over about 12. After two nights my AHI had jumped up to 8.4 (even with zero large leaks) so I changed the machine myself back to Bi-Level. My doc did authorize a reduction in pressures down to 15/11 and last night my AHI was 0.4. But to control leaks I'm having to screw down my Quattro FF mask to the point where I get the hamburger nose syndrome every morning.

I'm theorizing that something they did in the PS settings would not allow the machine to truly free-float between 5-25 cm but the doc's RRT swore it was set right. Here's the Encore Basic chart for that night.

Any thoughts would be appreciated. Theoretically anyway I would think that an automatic setting from 5-25 would be ideal in trying to control leaks, but it doesn't seem to work for me. I just can't figure why the pressures didn't get any higher than they did, obviously causing a rise in AHI.

[jgjones1972]

Sure looks to me like they only set IPAP to Auto and didn't set EPAP to Auto, but left it at a constant pressure of 5. I'm not all that familiar with your machine, but I'd be willing to bet that's the problem. Having exhale set so low probably kept the machine from raising inhale properly. I'm sure someone who uses an Auto Bi-level machine can shed some light on this.

Many RTs can't figure out how to set a regular APAP properly, but that doesn't keep them from trying (and then swearing they did it right) so I can only imagine the comedy of errors that can occur when one of them gets hold of an Auto Bi-level machine.

[RonWessels]

I agree. With EPAP fixed at 5, your PS (pressure support, or IPAP-EPAP) range of 2-8 means that, at most your IPAP is allowed to get to 5+8=13.

I also agree that an auto-bi-level-CPAP device is one of the most flexible systems, and therefore one of the most complicated to configure correctly.

[old dude]

Sure looks to me like they only set IPAP to Auto and didn't set EPAP to Auto, but left it at a constant pressure of 5. I'm not all that familiar with your machine, but I'd be willing to bet that's the problem. Having exhale set so low probably kept the machine from raising inhale properly. I'm sure someone who uses an Auto Bi-level machine can shed some light on this.

Many RTs can't figure out how to set a regular APAP properly, but that doesn't keep them from trying (and then swearing they did it right) so I can only imagine the comedy of errors that can occur when one of them gets hold of an Auto Bi-level machine.

I agree. With EPAP fixed at 5, your PS (pressure support, or IPAP-EPAP) range of 2-8 means that, at most your IPAP is allowed to get to 5+8=13.

I also agree that an auto-bi-level-CPAP device is one of the most flexible systems, and therefore one of the most complicated to configure correctly.

My machine is a PRS1 760P, and when put in automatic mode the only choices to set actual pressures are Minimum EPAP and Maximum IPAP. They were indeed set to 5cm and 25cm respectively. Beyond that the only other variable to set is Pressure Support. Max PS can be set from 0 to the minimum value of either 8cm or the difference between Max IPAP and Min EPAP. Min PS can be set from 0 up to the Max PS you just set. They set mine at Min=2cm and Max=8cm.

I should say that I overheard some "discussion" between my doc's RRT (who faxed the Rx over to my DME) and my DME who was making the changes to my machine. Evidently whoever won the argument was incorrect.