title: Bronchodilation in COPD: beyond FEV1-the effect of albuterol on resistive and reactive properties of the respiratory system.
abstract: OBJECTIVE
  Current debates on the bronchodilator response in COPD patients and whether the variation in FEV1 can be considered as an indicator of complete reversibility in such patients motivated us to conduct this study. The objective of the study was to determine the effect of albuterol on the resistive and reactive properties of the respiratory system in COPD patients.
  
  
  METHODS
  We evaluated 70 patients with COPD, divided into two groups based on spirometry findings: bronchodilator (BD)-negative (n = 39); and BD-positive (n = 31). We used the forced oscillation technique (FOT) to evaluate the following parameters: resistance at the intercept (R0), associated with the total resistance of the respiratory system; mean resistance (Rm), associated with central airway resistance; dynamic compliance (Cdyn); and the slope of resistance (S) and mean reactance (Xm), both of which are associated with the homogeneity of the respiratory system.
  
  
  RESULTS
  The use of albuterol resulted in significant reductions in (p < 0.00002) and Rm (p < 0.0002). There were also significant increases in S (p < 0.0001), Cdyn (p < 0.0001) R0 and Xm (p < 0.00004).These modifications occurred in both groups, the changes in FOT parameters being greater than those observed for spirometric parameters.
  
  
  CONCLUSIONS
  The use of albuterol improved the resistive and reactive properties of the respiratory system of the COPD patients under study. These changes occurred regardless of the FEV1-based classification, thereby indicating that the use of this parameter in isolation might not suffice to identify the physiological effects involved.
authors.affiliation: Rio de Janeiro State University, Rio de Janeiro, Brazil.
authors.forename: Gerusa Marítimo da
authors.initials: GM
authors.lastname: Costa
authors.forename: Alvaro Camilo Dias
authors.initials: AC
authors.lastname: Faria
authors.forename: Ana Maria Gonçalves Tavares
authors.initials: AM
authors.lastname: Di Mango
authors.forename: Agnaldo José
authors.initials: AJ
authors.lastname: Lopes
authors.forename: José Manoel
authors.initials: JM
authors.lastname: Jansen
authors.forename: Pedro Lopes de
authors.initials: PL
authors.lastname: Melo
mesh_terms: D000368:Aged; D000403:Airway Resistance / Q000187:drug effects*; D000420:Albuterol / Q000627:therapeutic use*; D001993:Bronchodilator Agents / Q000627:therapeutic use*; D005260:Female; D005541:Forced Expiratory Volume / Q000187:drug effects*; D006801:Humans; D008297:Male; D029424:Pulmonary Disease, Chronic Obstructive / Q000188:drug therapy*; D013147:Spirometry; D018709:Statistics, Nonparametric
chemical_list: D001993:Bronchodilator Agents; D000420:Albuterol