Need to suck for air in new BiPAP

[Benign]

I had been using a DreamStation Auto CPAP since November and recently was moved to an BiPAP.  The CPAP was able to bring my AHI down to the 6-10 level after my Dr moved me to a fixed CPAP setting of 14 cm, but that caused an uncomfortable number of Central Apneas.  A second PSG Titration study indicated I needed an Auto BiPAP with settings of IPAP 20 EPAP 9 and PS 4-8.  My DME sent me a DreamStation Auto BiPAP already configured with those settings, which I was able to confirm.  

I never felt air starvation or need to "suck" for air with my fixed CPAP at 13-14, but did with these settings on the Auto BiPAP.  OSCAR showed the pressure to be a consistent 13 with a few periodic jumps to 15 for a few minutes.  However CA's were still high at 23-25.   I discussed the issue with my DME and Dr who authorized me to change from BiPAP to fixed BiPAP with IPAP 17, EPAP 12 and a Rise of 1, which I am still at.  CA's are still running high at 36-51.  I have sent my DME and Dr copies of my OSCAR reports, but have yet to hear back.

Besides the high CA's on the BiPAP being much higher than on my CPAP, I have a real problem of having to "suck" for air and can even feel my ResMed AirTouch F20 mask contract when I breathe in.  The mask is not leaking (even though OSCAR's Leak graph is very odd in comparison to what I was seeing with my CPAP - an issue for another time).  I would hear or feel it if it was.  

I can't believe this is how BiPAP's are supposed to function.  I understand the machine needs to know when to change from exhale mode and pressure to the inhale mode and pressure, but it shouldn't require a draw for the entire inhale.  The DME is clueless.  (I think I know more about the machine than they do.)  

Breathing during my PSG Titration study was no problem at all; actually a pleasure compared to the problem I am having.  I realize the machines in the Sleep Lab are far more sophisticated and probably more like a BiPAP ST or ASV, but is this normal?  Do I need to obtain and attach a manometer to prove the issue?

   
   

[Sleeprider]

The problem is your doctor prescribed a BiPAP instead of an ASV. Your problem is central apnea caused by the constant pressure support of 5 cm, and no backup rate to correct the centrals. You are clearly getting plenty of air and pressure, so the sensation of not getting enough air is how you sense centrals. Do you have any results of sleep studies or titration studies that you could post? (please redact any personally identifying information). I think in the end you should ask for titration on ASV, in the meanwhile, try setting your BiPAP to lower pressure support levels. Moving to your previous minimum PS of 4.0 may help, but explore lower PS at 3.0 as well and observe which direction your results go, and how you feel. Lower PS should help to reduce the CA events. In BiPAP S mode, reducing PS means reducing IPAP, keeping EPAP at the same pressure.