passages: 2978
passages: document
passages: Assessment of acute bronchodilator effects from specific airway resistance changes in stable COPD patients . BACKGROUND In COPD patients , reversibility is currently evaluated from the changes of forced expiratory volume at 1s ( ΔFEV1 ) and forced vital capacity ( ΔFVC ) . By lowering peripheral airway smooth muscle tone , bronchodilators should decrease dynamic hyperinflation , gas trapping , and possibly dyspnea at rest . Hence , we hypothesize that specific airway resistance changes ( ΔsRAW ) should better characterize the acute response to bronchodilators . METHODS On two days , 60 COPD patients underwent dyspnea evaluation ( VAS score ) and pulmonary function testing at baseline and one hour after placebo or 300μg indacaterol administration . RESULTS Spirographic and ΔsRAW-based criteria identified as responders 24 and 45 patients , respectively . ΔsRAW correlated with changes of intrathoracic gas volume ( ΔITGV ) ( r=0.61 ; p < 0.001 ) , residual volume ( ΔRV ) ( r=0.60 ; p < 0.001 ) , ΔFVC ( r=0.44 ; p=0.001 ) , and ΔVAS ( r=0.73 ; p < 0.001 ) , while ΔFEV1 correlated only with ΔFVC ( r=0.34 ; p=0.008 ) . Significant differences in terms of ΔITGV ( p=0.002 ) , ΔRV ( p=0.023 ) , and ΔVAS ( p < 0.001 ) occurred only if patients were stratified according to ΔsRAW . CONCLUSIONS In assessing the acute functional effect of bronchodilators , ΔsRAW-based criterion is preferable to FEV1-FVC-based criteria , being more closely related to bronchodilator-induced improvements of lung mechanics and dyspnea at rest .
entities: 2979
entities: Intervention_Control
entities: placebo
entities: 2980
entities: Intervention_Pharmacological
entities: indacaterol
entities: 2981
entities: Outcome_Physical
entities: specific airway resistance changes ( ΔsRAW )
entities: 2982
entities: Outcome_Physical
entities: dyspnea evaluation ( VAS score )
entities: 2983
entities: Outcome_Physical
entities: pulmonary function
entities: 2984
entities: Outcome_Physical
entities: Spirographic
entities: 2985
entities: Outcome_Physical
entities: ΔsRAW-based
entities: 2986
entities: Outcome_Physical
entities: ΔsRAW
entities: 2987
entities: Outcome_Physical
entities: intrathoracic gas volume ( ΔITGV )
entities: 2988
entities: Outcome_Physical
entities: residual volume
entities: 2989
entities: Outcome_Physical
entities: ΔsRAW-based
entities: 2990
entities: Outcome_Physical
entities: FEV1-FVC-based
entities: 2991
entities: Participant_Condition
entities: stable COPD patients .
entities: 2992
entities: Participant_Condition
entities: COPD patients
entities: 2993
entities: Participant_Sample-size
entities: 60
entities: 2994
entities: Participant_Condition
entities: COPD