PURPOSE: Exhaled hydrogen peroxide level in breath condensate (eEHP) and exhaled nitric oxide (eNO) are considered as markers of airways inflammation in patients with chronic obstructive pulmonary disease (COPD)and asthma. Current study investigated the relationship between these markers and changes in large and small airways function in patients with COPD.
METHODS: Thirty four patients with COPD were evaluated by a pulmonologist in a university setting with full history, physical examination, and pulmonary function tests. The difference of FRCs measured by two methods of body-plethysmography and helium dilution was calculated. eNO was measured using Sievers280 eNO Analyzer (Sievers Bolder, CO) and EHP was measured in breath condensate taken by Cryocond (provided by Bohringer, Germany) using horseradish peroxidase method. The relationship between the EHP and various parameters of airflow and lung volumes was analyzed.
RESULTS: EPH had a significant and strong positive correlation with the difference of FRC measured by two methods of body-plethysmography and helium dilution ( r = 0.83; p = 009), RV/TLC (r= 0.69; p<.01), and with TLC % predicted (r= 0.58; p= 0.03) but not with FEV1%predicted or PEF% predicted. ENO had a significant positive correlation with RV % predicted and RV/TLC (r = 0.48; p=003) but not with FEV1% predicted or FRC difference in two techniques.
CONCLUSION: These results reveal a strong positive correlation between EHP and hyperinflation and air-trapping which is affected more dominantly by changes in small airways than large airways in patients with COPD and this relationship is more remarkable than that seen between eNO and these lung function parameters.
CLINICAL IMPLICATIONS: These findings are in line with the previous reports of more dominant inflammatory changes in small airways compared to large airways in COPD.
DISCLOSURE: Khalil Ansarin, No Financial Disclosure Information; No Product/Research Disclosure Information