First Step Toward Pneumonia Phenotyping by Breath Analysis with Constant and Temperature-Modulated SMOX Sensors

Pneumonia is one of the most diagnosed lung diseases worldwide. Yet, identifying its causes remains challenging. We developed an electronic nose (E-Nose) system that combines semiconducting metal-oxide (SMOX) gas sensors, operated at fixed and modulated temperatures, to diagnose the causes of pneumonia based on exhaled breath. A standardized breath collection protocol was implemented to enhance measurement reproducibility. The application of classification algorithms enabled preliminary discrimination between patients with pneumonia and healthy control subjects based on E-Nose responses. In the preliminary dataset, the temperature-modulated sensor achieved the highest accuracy (81%), slightly outperforming the fixed-temperature sensors. These results suggest that the E-Nose may enable rapid, non-invasive diagnosis of pneumonia, although further validation in a larger cohort is needed.