Association between acute tobacco exposure and fractional exhaled nitric oxide in patients with chronic obstructive pulmonary disease: National health and Nutrition Examination Survey (NHANES) 2007-2012.

Background: Fractional exhaled nitric oxide (FeNO) is a marker of type 2 airway inflammation. Tobacco exposure can lower FeNO levels. However, the effect of acute tobacco exposure on FeNO in patients with chronic obstructive pulmonary disease (COPD) is unclear.

Indicators for prediction of Mycobacterium tuberculosis positivity detected with bronchoalveolar lavage fluid.

Background: The diagnosis of active pulmonary tuberculosis (TB) remains a challenge in clinic, especially for sputum negative pulmonary TB. Bronchoalveolar lavage fluid (BALF) has higher sensitivity than sputum for detection of Mycobacterium tuberculosis (Mtb). However, bronchoscopy is invasive and costly, and not suitable for all patients.