TY - JOUR
T1 - Exercise-Induced Changes in Exhaled NO Differentiates Asthma with or Without Fixed Airway Obstruction from COPD with Dynamic Hyperinflation
AU - Huang, Shu Yi
AU - Chou, Pai Chien
AU - Wang, Tsai Yu
AU - Lo, Yu Lun
AU - Joa, Wen Ching
AU - Chen, Li Fei
AU - Sheng, Te Fang
AU - Chung, Kian Fan
AU - Wang, Chun Hua
AU - Kuo, Han Pin
PY - 2016/4/1
Y1 - 2016/4/1
N2 - Asthmatic patients with fixed airway obstruction (FAO) and patients with chronic obstructive pulmonary disease (COPD) share similarities in terms of irreversible pulmonary function impairment. Exhaled nitric oxide (eNO) has been documented as a marker of airway inflammation in asthma, but not in COPD. To examine whether the basal eNO level and the change after exercise may differentiate asthmatics with FAO from COPD, 27 normal subjects, 60 stable asthmatics, and 62 stable COPD patients were studied. Asthmatics with FAO (n=29) were defined as showing a postbronchodilator FEV 1/forced vital capacity (FVC) ≤70% and FEV 1 less than 80% predicted after inhaled salbutamol (400μg). COPD with dynamic hyperinflation (n=31) was defined as a decrease in inspiratory capacity (ΔIC%) after a 6 minute walk test (6MWT). Basal levels of eNO were significantly higher in asthmatics and COPD patients compared to normal subjects. The changes in eNO after 6MWT were negatively correlated with the percent change in IC (r=-0.380, n=29, P=0.042) in asthmatics with FAO. Their levels of basal eNO correlated with the maximum mid-expiratory flow (MMEF % predicted) before and after 6MWT. In COPD patients with air-trapping, the percent change of eNO was positively correlated to ΔIC% (rs=0.404, n=31, P=0.024). We conclude that asthma with FAO may represent residual inflammation in the airways, while dynamic hyperinflation in COPD may retain NO in the distal airspace. eNO changes after 6MWT may differentiate the subgroups of asthma or COPD patients and will help toward delivery of individualized therapy for airflow obstruction.
AB - Asthmatic patients with fixed airway obstruction (FAO) and patients with chronic obstructive pulmonary disease (COPD) share similarities in terms of irreversible pulmonary function impairment. Exhaled nitric oxide (eNO) has been documented as a marker of airway inflammation in asthma, but not in COPD. To examine whether the basal eNO level and the change after exercise may differentiate asthmatics with FAO from COPD, 27 normal subjects, 60 stable asthmatics, and 62 stable COPD patients were studied. Asthmatics with FAO (n=29) were defined as showing a postbronchodilator FEV 1/forced vital capacity (FVC) ≤70% and FEV 1 less than 80% predicted after inhaled salbutamol (400μg). COPD with dynamic hyperinflation (n=31) was defined as a decrease in inspiratory capacity (ΔIC%) after a 6 minute walk test (6MWT). Basal levels of eNO were significantly higher in asthmatics and COPD patients compared to normal subjects. The changes in eNO after 6MWT were negatively correlated with the percent change in IC (r=-0.380, n=29, P=0.042) in asthmatics with FAO. Their levels of basal eNO correlated with the maximum mid-expiratory flow (MMEF % predicted) before and after 6MWT. In COPD patients with air-trapping, the percent change of eNO was positively correlated to ΔIC% (rs=0.404, n=31, P=0.024). We conclude that asthma with FAO may represent residual inflammation in the airways, while dynamic hyperinflation in COPD may retain NO in the distal airspace. eNO changes after 6MWT may differentiate the subgroups of asthma or COPD patients and will help toward delivery of individualized therapy for airflow obstruction.
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U2 - 10.1097/MD.0000000000003400
DO - 10.1097/MD.0000000000003400
M3 - Article
C2 - 27082615
AN - SCOPUS:84964584125
VL - 95
JO - Medicine; analytical reviews of general medicine, neurology, psychiatry, dermatology, and pediatries
JF - Medicine; analytical reviews of general medicine, neurology, psychiatry, dermatology, and pediatries
SN - 0025-7974
IS - 15
M1 - e3400
ER -