Inspiratory capacity, exercise limitation, markers of severity, and prognostic factors in chronic obstructive pulmonary disease.
OBJECTIVE
To correlate the postbronchodilator (post-BD) inspiratory capacity (IC), % of predicted, with other markers of severity and prognostic factors in chronic obstructive pulmonary disease (COPD).


METHODS
Eighty stable patients with COPD performed forced vital capacity and slow vital capacity maneuvers, as well as the 6-min walk test, prior to and after receiving albuterol spray (400 microg). Patients were divided into four groups, based on post-BD forced expiratory volume in one second. Several variables were tested to establish correlations with the post-BD distance walked, using univariate and multivariate analysis. Post-BD IC was found to correlated with Global Initiative for Chronic Obstructive Lung Disease (GOLD) staging and with the Body mass index, airway Obstruction, Dyspnea, and Exercise capacity (BODE) index.


RESULTS
Multivariate regression analysis revealed that the distance walked, % predicted, correlated significantly with the IC post-BD, % predicted (p = 0.001), long-term oxygen use (p = 0.014), and number of medications used in the treatment (p = 0.044). IC < 70% was observed in 56% patients in GOLD stages 3 or 4 vs. 20% in GOLD 1 or 2 (p < 0.001). IC < 70% was observed in (60%) patients with BODE score 3 or 4 vs. (33%) BODE score 1 or 2 (p = 0.02).


CONCLUSIONS
Post-BD IC% predicted is the best functional predictor of distance walked and is significantly associated with GOLD staging and BODE index. Therefore, We propose that the inspiratory capacity should be added to the routine evaluation of the COPD patients.
Freitas
Clarice Guimarães de
CG
Universidade de Brasília, Brasilia, DF, Brasil. claricegfs@terra.com.br
Pereira
Carlos Alberto de Castro
CA
Viegas
Carlos Alberto de Assis
CA
D000368:Aged; D000402:Airway Obstruction / Q000503:physiopathology; D000420:Albuterol / Q000008:administration & dosage*; D015992:Body Mass Index; D001993:Bronchodilator Agents / Q000008:administration & dosage*; D003430:Cross-Sectional Studies; D004417:Dyspnea / Q000503:physiopathology; D005080:Exercise Test / Q000187:drug effects / Q000379:methods; D017079:Exercise Tolerance / Q000187:drug effects / Q000502:physiology; D005260:Female; D005541:Forced Expiratory Volume / Q000187:drug effects / Q000502:physiology; D006801:Humans; D007320:Inspiratory Capacity / Q000187:drug effects / Q000502:physiology; D008297:Male; D011379:Prognosis; D029424:Pulmonary Disease, Chronic Obstructive / Q000175:diagnosis* / Q000503:physiopathology; D012044:Regression Analysis; D012720:Severity of Illness Index; D018709:Statistics, Nonparametric; D013997:Time Factors; D014797:Vital Capacity / Q000187:drug effects / Q000502:physiology; D016138:Walking / Q000502:physiology
D001993:Bronchodilator Agents; D000420:Albuterol