Figure 1
An example of the raw data that was analyzed from exhaled breath measurements. The third panel represents the partial pressure of expired oxygen. The long exhalation represents a voluntary deep exhalation, done on command as part of the data collection protocol. The superimposed dotted line hypothetically represents the regression equation where the zero slope portion, denoted by the arrow, represents the steady-state estimate of the partial pressure of oxygen in mixed venous blood. Inspiratory, expiratory and deep exhale cycles are annotated on the figure. CO2 – carbon dioxide; Vol – volume; O2 – oxygen.