title: Small airway dysfunction and flow and volume bronchodilator responsiveness in patients with chronic obstructive pulmonary disease.
abstract: BACKGROUND
  We investigated whether a relationship between small airways dysfunction and bronchodilator responsiveness exists in patients with chronic obstructive pulmonary disease (COPD).
  
  
  METHODS
  We studied 100 (20 female; mean age: 68±10 years) patients with COPD (forced expiratory volume in 1 second [FEV1]: 55% pred ±21%; FEV1/forced vital capacity [FVC]: 53%±10%) by impulse oscillometry system. Resistance at 5 Hz and 20 Hz (R5 and R20, in kPa·s·L(-1)) and the fall in resistance from 5 Hz to 20 Hz (R5 - R20) were used as indices of total, proximal, and peripheral airway resistance; reactance at 5 Hz (X5, in kPa·s·L(-1)) was also measured. Significant response to bronchodilator (salbutamol 400 μg) was expressed as absolute (≥0.2 L) and percentage (≥12%) change relative to the prebronchodilator value of FEV1 (flow responders, FRs) and FVC (volume responders, VRs).
  
  
  RESULTS
  Eighty out of 100 participants had R5 - R20 >0.03 kPa·s·L(-1) (> upper normal limit) and, compared to patients with R5 - R20 ≤0.030 kPa·s·L(-1), showed a poorer health status, lower values of FEV1, FVC, FEV1/FVC, and X5, along with higher values of residual volume/total lung capacity and R5 (P<0.05 for all comparisons). Compared to the 69 nonresponders and the 8 FRs, the 16 VRs had significantly higher R5 and R5 - R20 values (P<0.05), lower X5 values (P<0.05), and greater airflow obstruction and lung hyperinflation.
  
  
  CONCLUSIONS
  This study shows that peripheral airway resistance is increased in the vast majority of patients with COPD, who showed worse respiratory reactance, worse spirometry results, more severe lung hyperinflation, and poorer health status. Small airway dysfunction was also associated with the bronchodilator responsiveness in terms of FVC, but not in terms of FEV1.
authors.affiliation: Department of Clinical and Experimental Medicine, University of Parma, Parma, Italy.
authors.forename: Roberta
authors.initials: R
authors.lastname: Pisi
authors.affiliation: Department of Clinical and Experimental Medicine, University of Parma, Parma, Italy.
authors.forename: Marina
authors.initials: M
authors.lastname: Aiello
authors.affiliation: Division of Pneumology, IRCCS Rehabilitation Institute of Tradate, Salvatore Maugeri Foundation, Tradate, Italy.
authors.forename: Andrea
authors.initials: A
authors.lastname: Zanini
authors.affiliation: Department of Clinical and Experimental Medicine, University of Parma, Parma, Italy.
authors.forename: Panagiota
authors.initials: P
authors.lastname: Tzani
authors.affiliation: Medical Department, Chiesi Farmaceutici SpA, Parma, Italy.
authors.forename: Davide
authors.initials: D
authors.lastname: Paleari
authors.affiliation: Department of Clinical and Experimental Medicine, University of Parma, Parma, Italy.
authors.forename: Emilio
authors.initials: E
authors.lastname: Marangio
authors.affiliation: Division of Pneumology, IRCCS Rehabilitation Institute of Tradate, Salvatore Maugeri Foundation, Tradate, Italy ; Department of Clinical and Experimental Medicine, University of Insubria, Varese, Italy.
authors.forename: Antonio
authors.initials: A
authors.lastname: Spanevello
authors.affiliation: Corporate Clinical Development, Chiesi Farmaceutici SpA, Parma, Italy.
authors.forename: Gabriele
authors.initials: G
authors.lastname: Nicolini
authors.affiliation: Department of Clinical and Experimental Medicine, University of Parma, Parma, Italy.
authors.forename: Alfredo
authors.initials: A
authors.lastname: Chetta
mesh_terms: D058666:Adrenergic beta-2 Receptor Agonists / Q000627:therapeutic use*; D000368:Aged; D000403:Airway Resistance / Q000187:drug effects*; D000420:Albuterol / Q000627:therapeutic use*; D001980:Bronchi / Q000187:drug effects* / Q000503:physiopathology; D001993:Bronchodilator Agents / Q000627:therapeutic use*; D003430:Cross-Sectional Studies; D005260:Female; D005541:Forced Expiratory Volume; D006304:Health Status; D006801:Humans; D008297:Male; D008875:Middle Aged; D009991:Oscillometry; D029424:Pulmonary Disease, Chronic Obstructive / Q000175:diagnosis / Q000188:drug therapy / Q000503:physiopathology; D013147:Spirometry; D016896:Treatment Outcome; D014797:Vital Capacity
chemical_list: D058666:Adrenergic beta-2 Receptor Agonists; D001993:Bronchodilator Agents; D000420:Albuterol
keywords: COPD; bronchodilator responsiveness; small airways