FIG. 26:  Another study that compared ASV (ASVAuto) with BiPAP ST also showed the superior effect of ASV in reducing total AHI, as well as the CAI.^[22]  Although it is unclear what type of CSA was exhibited by the patients in this study, the results showed that ASV improved total AHI, CAI, and respiratory arousal index (RAI).  ASV normalized respiration in 83% of the patients compared to only 33% in the BIPAP ST group.  There was no difference in the mean or nadir SPO₂, and there was no difference in the 95th percentile pressure for IPAP or EPAP between ASV and BiPAP ST. 

In response to the Morning After Patient Satisfaction Questionnaire, patients who were on ASV reported feeling more awake and alert, and there was no difference between ASV and bilevel PAP in terms of comfort (PAP Comfort Questionnaire).  These effects of ASV on Op-CSA differed from the rather mixed results from early studies, and it is unclear how much the different machines or settings or titration protocols or even the central apnea types might have affected these outcomes.