Fig. 2.

Breathing maneuvers and acquisition volumes used in this study. Solid gray lines indicate an inhalation from a 1-liter bag, solid black lines indicate an exhalation and dashed gray lines indicate an inhalation of room air. Solid boxes represent acquisition volumes and dashed boxes represent intermediate volumes as part of the breathing maneuver. RV, residual volume; RV + 1L, residual volume plus 1 liter of gas mixture; FRC, functional residual capacity; FRC + 1L, functional residual capacity volume plus 1 liter of gas mixture; TLC, total lung capacity.