title: Lung mechanics and dyspnea during exacerbations of chronic obstructive pulmonary disease.
abstract: BACKGROUND
  Exacerbation of chronic obstructive pulmonary disease commonly causes hospitalization. The change in lung mechanics during exacerbation and its relationship to symptoms in spontaneously breathing individuals has not been described.
  
  
  OBJECTIVE
  We hypothesized that changes in both airflow and lung volumes would occur during an exacerbation, but that only volume change would relate to symptomatic improvement.
  
  
  METHODS
  Lung mechanics and resting dyspnea were recorded in 22 hospitalized patients during recovery from exacerbation.
  
  
  METHODS
  Spirometry, inspiratory capacity, respiratory system resistance and reactance, tidal breathing patterns, and expiratory flow limitation were recorded after nebulized bronchodilator therapy on the first 3 d after admission, at discharge, and 6 wk postadmission (Day 42). Prebronchodilator measurements were taken on Day 2, at discharge, and on Day 42.
  
  
  RESULTS
  Postbronchodilator inspiratory capacity increased 0.23 +/- 0.07 L by discharge and 0.42 +/- 0.1 L by Day 42, FEV1 rose 0.09 +/- 0.04 and 0.2 +/- 0.05 L at discharge and Day 42, respectively, and FVC increased 0.21 +/- 0.08 and 0.47 +/- 0.09 L at discharge and Day 42 (all p < 0.05). Consistent reduction in dyspnea was seen as the exacerbation resolved. Respiratory system resistance, FEV1/FVC, and expiratory flow limitation were unchanged throughout, indicating that changes in lung volume rather than airflow resistance predominated.
  
  
  CONCLUSIONS
  Improvement in operating lung volumes is the principal change seen as a chronic obstructive pulmonary disease exacerbation resolves and increase in inspiratory capacity is a useful guide to a reduction in dyspnea.
authors.affiliation: Department of Medicine, Clinical Sciences Centre, University Hospital Aintree, Longmoor Lane, Liverpool L9 7AL, UK.
authors.forename: Nicola J
authors.initials: NJ
authors.lastname: Stevenson
authors.forename: Paul P
authors.initials: PP
authors.lastname: Walker
authors.forename: Richard W
authors.initials: RW
authors.lastname: Costello
authors.forename: Peter M A
authors.initials: PM
authors.lastname: Calverley
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000403:Airway Resistance; D001993:Bronchodilator Agents / Q000627:therapeutic use; D004417:Dyspnea / Q000188:drug therapy / Q000209:etiology / Q000503:physiopathology*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008176:Lung Volume Measurements; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D029424:Pulmonary Disease, Chronic Obstructive / Q000150:complications / Q000188:drug therapy / Q000503:physiopathology*; D015656:Respiratory Mechanics / Q000502:physiology*; D013147:Spirometry; D016896:Treatment Outcome
chemical_list: D001993:Bronchodilator Agents