Figure 3. Overall effect of acetazolamide on the physiological traits.

Median data of resting ventilation and the four physiological traits at baseline (A) and during acetazolamide treatment (B) from all 12 subjects. Administration of acetazolamide significantly increased resting ventilation (P < 0.001) during stable NREM sleep and reduced LG (P < 0.05). However, administration of acetazolamide did not significantly alter the remaining traits. Note that the reduction in LG decreases the distance between the steady-state intersection and the arousal threshold from 3.6 l min⁻¹ to 1.2 l min⁻¹ (i.e. the steady-state intersection is closer to the stable region). However, the intersection has not crossed over into the stable region, which may explain the ability of acetazolamide to reduce, but not eliminate, OSA.