Chronic bronchitis leads to accelerated hyperinflation in COPD patients during exercise. Issue 4 (19th March 2015)

• Record Type: Journal Article
• Authors: Zhang, Wen; Lu, Haitao; Peng, Liyue; Ren, Xiaoxia; Lu, Yong; An, Li; Zhang, Hong; Tan, Xiaoyue; Sun, Xingguo; Huang, Kewu
• Is Part Of: Respirology. Volume 20:Issue 4(2015)
• Page Start: 618
• Page End: 625
• Publication Date: 2015-03-19
• Subjects: Respiratory organs -- Diseases -- Periodicals; Respiratory organs -- Periodicals; 612.2
• DOI: 10.1111/resp.12504
• Languages: English
• ISSNs: 1323-7799

Abstract

<abstract abstract-type="main"> <title>Abstract</title> <sec id="resp12504-sec-0001" sec-type="section"> <title>Background and objective</title> <p>It is not known whether patients with chronic obstructive pulmonary disease (COPD) have a different exercise capacity with (CB<sup>+</sup>) or without accompanying chronic bronchitis (CB<sup>−</sup>).</p> </sec> <sec id="resp12504-sec-0002" sec-type="section"> <title>Methods</title> <p>We conducted spirometry, a 6‐min walk distance test and cardiopulmonary exercise test in 50 age‐matched healthy control subjects, 45 COPD patients without CB (CB<sup>−</sup>) and 37 COPD patients with CB (CB<sup>+</sup>). A multiple regression model was established to identify factors independently associated with peak oxygen consumption (<inline-formula><alternatives><inline-graphic mimetype="image" xlink:href="ark:/27927/pgjj8w5bm9" xlink:type="simple" xmlns:xlink="http://www.w3.org/1999/xlink" /><mml:math altimg="urn:x-wiley:13237799:media:resp12504:resp12504-math-5005" display="inline" overflow="scroll" xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:msub><mml:mover accent="true"><mml:mi mathvariant="bold">V</mml:mi><mml:mo mathvariant="bold">˙</mml:mo></mml:mover><mml:mrow><mml:msub><mml:mi mathvariant="bold">O</mml:mi><mml:mn mathvariant="bold">2</mml:mn></mml:msub></mml:mrow></mml:msub></mml:mrow></mml:math></alternatives></inline-formula>).</p> </sec> <sec id="resp12504-sec-0003" sec-type="section"> <title>Results</title> <p>Patients with and without CB had similar forced expiratory volume in 1 s (FEV<sub>1</sub>). CB<sup>+</sup> patients had a lower <inline-formula><alternatives><inline-graphic mimetype="image" xlink:href="ark:/27927/pgjj8w5bks" xlink:type="simple" xmlns:xlink="http://www.w3.org/1999/xlink" /><mml:math altimg="urn:x-wiley:13237799:media:resp12504:resp12504-math-5006" display="inline" overflow="scroll" xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:msub><mml:mover accent="true"><mml:mi mathvariant="bold">V</mml:mi><mml:mo mathvariant="bold">˙</mml:mo></mml:mover><mml:mrow><mml:msub><mml:mi mathvariant="bold">O</mml:mi><mml:mn mathvariant="bold">2</mml:mn></mml:msub></mml:mrow></mml:msub></mml:mrow></mml:math></alternatives></inline-formula>. CB<sup>+</sup> and CB<sup>−</sup> participants had similar increases in tidal volume at peak exercise; however, CB<sup>+</sup> patients had an increased respiratory rate (RR). These patients reached the peak value for ratio of end‐expiratory lung volume to total lung capacity (TLC) at a lower work load. A stepwise multiple linear regression analysis identified chronic bronchitis, FEV<sub>1</sub>, diffusing capacity for carbon monoxide, the ratio of residual volume to TLC and serum tumour necrosis factor‐α as independent predictors of peak <inline-formula><alternatives><inline-graphic mimetype="image" xlink:href="ark:/27927/pgjj8w5bnt" xlink:type="simple" xmlns:xlink="http://www.w3.org/1999/xlink" /><mml:math altimg="urn:x-wiley:13237799:media:resp12504:resp12504-math-5007" display="inline" overflow="scroll" xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:msub><mml:mover accent="true"><mml:mi mathvariant="bold">V</mml:mi><mml:mo mathvariant="bold">˙</mml:mo></mml:mover><mml:mrow><mml:msub><mml:mi mathvariant="bold">O</mml:mi><mml:mn mathvariant="bold">2</mml:mn></mml:msub></mml:mrow></mml:msub></mml:mrow></mml:math></alternatives></inline-formula>.</p> </sec> <sec id="resp12504-sec-0004" sec-type="section"> <title>Conclusions</title> <p>CB significantly lowers exercise capacity in COPD patients because of dynamic hyperinflation during exercise. The accelerated dynamic hyperinflation may contribute to increased airway and systemic inflammation in COPD patients.</p> </sec> </abstract>