title: Functional imaging using computer methods to compare the effect of salbutamol and ipratropium bromide in patient-specific airway models of COPD.
abstract: BACKGROUND
  Salbutamol and ipratropium bromide improve lung function in patients with chronic obstructive pulmonary disease (COPD). However, their bronchodilating effect has not yet been compared in the central and distal airways. Functional imaging using computational fluid dynamics offers the possibility of making such a comparison. The objective of this study was to assess the effects of salbutamol and ipratropium bromide on the geometry and computational fluid dynamics-based resistance of the central and distal airways.
  
  
  METHODS
  Five patients with Global Initiative for Chronic Obstructive Lung Disease Stage III COPD were randomized to a single dose of salbutamol or ipratropium bromide in a crossover manner with a 1-week interval between treatments. Patients underwent lung function testing and a multislice computed tomography scan of the thorax that was used for functional imaging. Two hours after dosing, the patients again underwent lung function tests and repeat computed tomography.
  
  
  RESULTS
  Lung function parameters, including forced expiratory volume in 1 second, vital capacity, overall airway resistance, and specific airway resistance, changed significantly after administration of each product. On functional imaging, the bronchodilating effect was greater in the distal airways, with a corresponding drop in airway resistance, compared with the central airways. Salbutamol and ipratropium bromide were equally effective at first glance when looking at lung function tests, but when viewed in more detail with functional imaging, hyporesponsiveness could be shown for salbutamol in one patient. Salbutamol was more effective in the other patients.
  
  
  CONCLUSIONS
  This pilot study gives an innovative insight into the modes of action of salbutamol and ipratropium bromide in patients with COPD, using the new techniques of functional imaging and computational fluid dynamics.
authors.affiliation: Department of Respiratory Medicine, Antwerp University Hospital, Antwerp, Belgium. Lieve.debacker@ua.ac.be
authors.forename: L A
authors.initials: LA
authors.lastname: De Backer
authors.forename: W G
authors.initials: WG
authors.lastname: Vos
authors.forename: R
authors.initials: R
authors.lastname: Salgado
authors.forename: J W
authors.initials: JW
authors.lastname: De Backer
authors.forename: A
authors.initials: A
authors.lastname: Devolder
authors.forename: S L
authors.initials: SL
authors.lastname: Verhulst
authors.forename: R
authors.initials: R
authors.lastname: Claes
authors.forename: P R
authors.initials: PR
authors.lastname: Germonpré
authors.forename: W A
authors.initials: WA
authors.lastname: De Backer
mesh_terms: D000368:Aged; D000420:Albuterol / Q000627:therapeutic use; D001993:Bronchodilator Agents / Q000627:therapeutic use; D018592:Cross-Over Studies; D005260:Female; D006801:Humans; D057446:Hydrodynamics; D009241:Ipratropium / Q000627:therapeutic use; D008297:Male; D008875:Middle Aged; D010865:Pilot Projects; D029424:Pulmonary Disease, Chronic Obstructive / Q000000981:diagnostic imaging* / Q000188:drug therapy* / Q000503:physiopathology; D012129:Respiratory Function Tests; D014057:Tomography, X-Ray Computed; D016896:Treatment Outcome
chemical_list: D001993:Bronchodilator Agents; D009241:Ipratropium; D000420:Albuterol