Requires only a LFX software option: Capnovolumetry (with ScoutTube) is the analysis of the exhaled CO2 compared to the exhaled volume. The CO2 concentration of exhaled air is plotted against the exhaled volume and thereby the anatomical airway dead space as well as the functional airway dead space can be determined. This method is independent of patient cooperation and therefore especially useful for monitoring respiratory diseases in both pediatric and geriatric patients.

Example graphs of capnovolumetry in patients with COPD of GOLD 2 and 3 severity, and in patients with and without emphysema. With increasing severity as well as the presence of emphysema, phase 3 becomes steeper and the difference in the slope to phase 2 becomes smaller, correspondingly the quotient s3/s2 becomes larger.
Example graph