Airflow limitation or static hyperinflation: which is more closely related to dyspnea with activities of daily living in patients with COPDReport as inadecuate

Airflow limitation or static hyperinflation: which is more closely related to dyspnea with activities of daily living in patients with COPD - Download this document for free, or read online. Document in PDF available to download.

Respiratory Research

, 12:135

First Online: 01 December 2011Received: 30 June 2011Accepted: 11 October 2011


BackgroundDyspnea while performing the activities of daily living has been suggested to be a better measurement than peak dyspnea during exercise. Furthermore, the inspiratory capacity IC has been shown to be more closely related to exercise tolerance and dyspnea than the FEV1, because dynamic hyperinflation is the main cause of shortness of breath in patients with COPD. However, breathlessness during exercise is measured in most studies to evaluate this relationship.

PurposeTo evaluate the correlation between breathlessness during daily activities and airflow limitation or static hyperinflation in COPD.

MethodsWe examined 167 consecutive outpatients with stable COPD. The Baseline Dyspnea Index BDI was used to evaluate dyspnea with activities of daily living. The relationship between the BDI score and the clinical measurements of pulmonary function was then investigated.

ResultsThe Spearman rank correlation coefficients Rs between the BDI score and the FEV1L, FEV1%pred and FEV1-FVC were 0.60, 0.56 and 0.56, respectively. On the other hand, the BDI score also correlated with the IC, IC-predicted total lung capacity TLC and IC-TLC Rs = 0.45, 0.46 and 0.47, respectively. Although all of the relationships studied were strongly correlated, the correlation coefficients were better between dyspnea and airflow limitation than between dyspnea and static hyperinflation. In stepwise multiple regression analyses, the BDI score was most significantly explained by the FEV1 R = 26.2% and the diffusion capacity for carbon monoxide R = 14.4% Cumulative R = 40.6%. Static hyperinflation was not a significant factor for clinical dyspnea on the stepwise multiple regression analysis.

ConclusionBoth static hyperinflation and airflow limitation contributed greatly to dyspnea in COPD patients.

KeywordsChronic obstructive pulmonary disease Airflow limitation Hyperinflation Dyspnea Baseline Dyspnea Index AbbreviationsCOPDchronic obstructive pulmonary disease

ICinspiratory capacity

FEV1forced expiratory volume in 1 second

FVCforced vital capacity

TLCtotal lung capacity

BDIBaseline Dyspnea Index

ABGarterial blood gas

RVresidual volume

DLcodiffusion capacity for carbon monoxide

BNPbrain natriuretic peptide

BMIbody mass index

EELVend-expiratory lung volume

TLcotransfer factor for carbon monoxide

Electronic supplementary materialThe online version of this article doi:10.1186-1465-9921-12-135 contains supplementary material, which is available to authorized users.

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Author: Koichi Nishimura - Maya Yasui - Takashi Nishimura - Toru Oga


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