Sleep doc only wants CPAP, not APAP

[tedburnsIII]

For those interested in how sleep technologists recommend an optimal or other fixed pressure, click on this link:

http://www.aasmnet.org/Resources/clinica...040210.pdf

[PaytonA]

Payton, the pressure reduction in EPAP allows more air to be exhaled by some people than exhalation against pressure. The tidal volume can be influenced by setting the pressure support. In fact, if set too high it can induce centrals by purging too much CO2. This link explains how tidal volume can be targeted by pressure support: http://www.healthcare.philips.com/main/h.../setup.wpd Bilevel therapy is commonly used in COPD, chronic obstructive, asthma, and other patients to improve volume and ease breathing, but the same principles apply to pretty much anyone. In my own case, my tidal volume on APAP at 11-14 averages in the mid to upper 540 to 610 mL range. With BiPAP Min EPAP 8.0 Max IPAP 18.0 PS 5.0-8.0 (cmH2O), the tidal volume average 630 to 680.

Maybe this is just my misunderstanding but this link points to setup for a BiPAP AVAPS not a simple BiPAP or BiPAP auto. Different animal entirely.

Your comparison of tidal volume with more pressure relief on exhalation has more potentially changed than just the pressure support.

You can pretty accurately target tidal volume with BiPAP settings and have much more influence on overall blood oxygen levels than with CPAP. Keep in mind, the use of EPR and Flex, there is a low level of pressure support in many CPAP and APAP machines, but if ventilation (oxygenation) is a concern, most doctors will turn to Bilevel.

Tidal volume is not the only driving force for oxygenation.

It seems to be common (at least I have noticed it with the Resmed folk) to call their ASV or ST or AVAPS machines bilevel machines. They are all bilevel but they are somewhat more than a simple VPAP S or VPAP Auto machine. I am afraid that it can be confusing to some including me. I think that, if we are talking about a bilevel machine with a backup rate, we should make that clear.

Best Regards,

PaytonA