Document Detail


The connection between chronic obstructive pulmonary disease symptoms and hyperinflation and its impact on exercise and function.
MedLine Citation:
PMID:  16996896     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
Forced expiratory volume in 1 second (FEV1) has served as an important diagnostic measurement of chronic obstructive pulmonary disease (COPD) but has not been found to correlate with patient-centered outcomes such as exercise tolerance, dyspnea, or health-related quality of life. It has not helped us understand why some patients with severe FEV1 impairment have better exercise tolerance compared with others with similar FEV1 values. Hyperinflation, or air trapping caused by expiratory flow limitation, causes operational lung volumes to increase and even approach the total lung capacity (TLC) during exercise. Some study findings suggest that a dyspnea limit is reached when the end-inspiratory lung volume encroaches within approximately 500 mL of TLC. The resulting limitation in daily physical activity establishes a cycle of decline that includes physical deconditioning (elevated blood lactic acid levels at lower levels of exercise) and worsening dyspnea. Hyperinflation is reduced by long-acting bronchodilators that reduce airways resistance. The deflation of the lungs, in turn, results in an increased inspiratory capacity. For example, the once-daily anticholinergic bronchodilator tiotropium increases inspiratory capacity, 6-minute walk distance, and cycle exercise endurance time, and it decreases isotime fatigue or dyspnea. Pulmonary rehabilitation and oxygen therapy both reduce ventilatory requirements and improve breathing efficiency, thereby reducing hyperinflation and improving exertional dyspnea. Thus, hyperinflation is directly associated with patient-centered outcomes such as dyspnea and exercise limitation. Furthermore, therapeutic interventions--including pharmacotherapy and lung volume--reduction surgery--that reduce hyperinflation improve these outcomes.
Authors:
Christopher B Cooper
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Publication Detail:
Type:  Journal Article; Review    
Journal Detail:
Title:  The American journal of medicine     Volume:  119     ISSN:  1555-7162     ISO Abbreviation:  Am. J. Med.     Publication Date:  2006 Oct 
Date Detail:
Created Date:  2006-09-25     Completed Date:  2006-09-29     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  0267200     Medline TA:  Am J Med     Country:  United States    
Other Details:
Languages:  eng     Pagination:  21-31     Citation Subset:  AIM; IM    
Affiliation:
Division of Pulmonary and Critical Care Medicine, Department of Medicine, David Geffen School of Medicine at UCLA, University of California-Los Angeles, Los Angeles, California 90095-1690, USA. ccooper@mednet.ucla.edu
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MeSH Terms
Descriptor/Qualifier:
Bronchodilator Agents / administration & dosage,  pharmacology
Dyspnea / drug therapy,  etiology
Exercise
Exercise Tolerance* / drug effects
Health Status
Humans
Inspiratory Capacity* / drug effects
Pulmonary Disease, Chronic Obstructive / complications,  drug therapy,  physiopathology*,  surgery
Quality of Life*
Scopolamine Derivatives / administration & dosage,  pharmacology
Chemical
Reg. No./Substance:
0/Bronchodilator Agents; 0/Scopolamine Derivatives; 136310-93-5/tiotropium

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


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