title: Bronchodilator response of advanced lung function parameters depending on COPD severity.
abstract: BACKGROUND
  COPD is defined as partly irreversible airflow obstruction. The response pattern of bronchodilators has not been followed in advanced lung function parameters.
  
  
  OBJECTIVE
  The aim of this study was to investigate bronchodilator response pattern in advanced lung function parameters in a continuous fashion along forced expiratory volume in 1 second (FEV1) percent predicted (%p) in COPD patients and controls.
  
  
  METHODS
  Eighty-one smokers/ex-smokers (41 controls and 40 COPD) performed spirometry, body plethysmography, impulse oscillometry and single-breath helium dilution carbon monoxide diffusion at baseline, after salbutamol inhalation and then after an additional inhalation of ipratropium.
  
  
  RESULTS
  Most pulmonary function parameters showed a linear increase in response to decreased FEV1%p. The subjects were divided into groups of FEV1%p <65 and >65, and the findings from continuous analysis were verified. The exceptions to this linear response were inspiratory capacity (IC), forced vital capacity (FVC), FEV1/FVC and expiratory resistance (Rex), which showed a segmented response relationship to FEV1%p. IC and FVC, with break points (BP) of 57 and 58 FEV1%p respectively, showed no response above, but an incresed slope below the BP. In addition, in patients with FEV1%p <65 and >65, response of FEV1%p did not correlate to response of volume parameters.
  
  
  CONCLUSIONS
  Response of several advanced lung function parameters differs depending on patients' baseline FEV1%p, and specifically response of volume parameters is most pronounced in COPD patients with FEV1%p <65. Volume and resistance responses do not follow the flow response measured with FEV1and may thus be used as a complement to FEV1reversibility to identify flow, volume and resistance responders.
authors.affiliation: Respiratory Medicine and Allergology, Department of Clinical Sciences Lund, Lund University.
authors.forename: Linnea
authors.initials: L
authors.lastname: Jarenbäck
authors.affiliation: Respiratory Medicine and Allergology, Department of Clinical Sciences Lund, Lund University.
authors.forename: Göran
authors.initials: G
authors.lastname: Eriksson
authors.affiliation: Regional Cancer Center South, Skåne University Hospital, Lund, Sweden.
authors.forename: Stefan
authors.initials: S
authors.lastname: Peterson
authors.affiliation: Respiratory Medicine and Allergology, Department of Clinical Sciences Lund, Lund University.
authors.forename: Jaro
authors.initials: J
authors.lastname: Ankerst
authors.affiliation: Respiratory Medicine and Allergology, Department of Clinical Sciences Lund, Lund University.
authors.forename: Leif
authors.initials: L
authors.lastname: Bjermer
authors.affiliation: Respiratory Medicine and Allergology, Department of Clinical Sciences Lund, Lund University.
authors.forename: Ellen
authors.initials: E
authors.lastname: Tufvesson
mesh_terms: D000280:Administration, Inhalation; D058666:Adrenergic beta-2 Receptor Agonists / Q000008:administration & dosage*; D000368:Aged; D000403:Airway Resistance; D000420:Albuterol / Q000008:administration & dosage*; D001993:Bronchodilator Agents / Q000008:administration & dosage*; D016022:Case-Control Studies; D018680:Cholinergic Antagonists / Q000008:administration & dosage*; D005260:Female; D005541:Forced Expiratory Volume; D006801:Humans; D009241:Ipratropium / Q000008:administration & dosage*; D016014:Linear Models; D008168:Lung / Q000187:drug effects* / Q000503:physiopathology; D008297:Male; D008875:Middle Aged; D009991:Oscillometry; D010993:Plethysmography, Whole Body; D011237:Predictive Value of Tests; D011653:Pulmonary Diffusing Capacity; D029424:Pulmonary Disease, Chronic Obstructive / Q000175:diagnosis / Q000188:drug therapy* / Q000503:physiopathology; D012720:Severity of Illness Index; D013147:Spirometry; D016896:Treatment Outcome; D014797:Vital Capacity
chemical_list: D058666:Adrenergic beta-2 Receptor Agonists; D001993:Bronchodilator Agents; D018680:Cholinergic Antagonists; D009241:Ipratropium; D000420:Albuterol
keywords: COPD; IOS; body plethysmography; bronchodilation; lung function; reversibility