Thanks, jnk. I see from that comparison chart that Resmed now offers an S9 VPAP COPD model:
http://www.resmed.com/us/products/vpap_ ... nc=dealers
That S9 VPAP COPD is probably less expensive than the more versatile S9 VPAP ST-A w/iVAPS machine. Apparently what differentiates the S9 VPAP COPD model from the ordinary S9 VPAP-S is that the settings are all defaulted to COPD-typical values, to be used as INITIAL settings that require follow-up customization (IPAP, EPAP, TiMax, TiMin, Rise Time, Trigger Sensitivity, Cycle Sensitivity, PS). That's also what happens with settings when the S9 VPAP ST-A w/iVAPS is placed in COPD treatment mode: COPD-typical settings are defaulted as a starting point requiring patient-specific customization. Those COPD-typical settings encourage CO2 depletion in COPD patients. Additionally the higher PS value will mechanically offload more COPD-related work of breathing (WOB) than a lower PS setting would.
The possible show-stopper for you, Slinky, is that the S9 VPAP COPD model has no backup rate. And if you and your doctor are going to endeavor adding more oxygen, then it might be a good idea to use a machine with a backup rate to compensate for the iatrogenic respiratory-drive response we discussed
a few posts up. The volume assurance of iVAPS or AVAPS (but not offered on the VPAP COPD model) probably isn't a bad idea either. Slinky, I'd also suggest asking the doctor if it's a good idea to gradually edge up from 2L O2, allowing plenty of time for your respiratory drive to adapt to each smaller increment of supplemental O2. As COPD patients perfuse less O2 and retain more CO2 over time, their respiratory drives essentially re-adapt to those gradually changing chemoreceptor inputs (O2 and CO2). That gradual re-adaptation sometimes makes hypercapnic COPD patients more prone to an acutely reduced respiratory drive in response to supplemental O2.