Exhaled Breath Temperature in COPD

Chronic obstructive pulmonary disease (COPD) is one of the leading causes of morbidity and mortality worldwide. Finding patients with early COPD is already difficult, but even those have already an advanced disease in the biological point of view with irreversible lung damage. A lot of effort is done to find the parameters for detection of patients with early pathophysiological changes before they develop airflow limitation. The importance of this stage is recently recognized and has different labels as “pre-COPD” and “early COPD”. Exhaled breath temperature (EBT) is a non-invasive method to detect and monitor inflammation in the respiratory system. Most studies on EBT have been performed in asthma and showed the utility of this approach to assess changes in airway inflammation. In the COPD patients, the number of airways and their vasculature is reduced and EBT decreases proportionally to the level of destruction, but is still increased during the COPD exacerbation. In recent studies, change in EBT after smoking a cigarette in patients without a diagnosis of COPD was significantly predictive for disease progression after 2 years. Early interventions based on these results should be tested for efficacy in prevention of the development of overt COPD.