Figure 1.

$\stackrel{.}{\text{V}}$e by sleep–wakefulness state (left panel) and $\stackrel{.}{\text{V}}$e for the entire night (right panel) are plotted for nights when undergoing laboratory-based polysomnography performed while receiving four different ASV devices: ResMed S7 VPAP Adapt (S7 device), a later version of the S7 device (ResMed S9 VPAP Adapt; S9 device), a Philips ASV device (System One), and an updated version of the Philips ASV device (Dreamstation). Mean and SE bars are plotted. Note that $\stackrel{.}{\text{V}}$e for most devices was greater during wakefulness when compared with sleep. Also, the greatest $\stackrel{.}{\text{V}}$e is during wakefulness while receiving therapy via the S7 device. There was no order effect for randomization sequence with regard to the $\stackrel{.}{\text{V}}$e findings. *P < 0.05 when compared with Dreamstation device; ^#P < 0.05 when compared with S9 device; and ^$P < 0.05 when compared with System One. ASV = adaptive servo ventilation.