title: Unilateral extrapulmonary airway bypass in advanced emphysema.
abstract: BACKGROUND
  Gas trapping in emphysema results in resting and dynamic hyperinflation. We tested the hypothesis that a direct connection between the lung parenchyma and the atmosphere could increase expiratory flow and thereby potentially improve dyspnea through the relief of gas trapping.
  
  
  METHODS
  Ex vivo we studied 7 emphysematous lungs and 3 fibrotic lungs (as controls) and measured expiratory flow before and after airway bypass insertion during a forced maneuver in an artificial thorax. Pilot studies were conducted in vivo in 6 patients with advanced emphysema using a size 9 endotracheal tube as a bypass surgically placed through the chest wall into the upper lobe.
  
  
  RESULTS
  In the ex vivo emphysematous lungs the volume expelled during a forced expiratory maneuver increased from 169 to 235 mL (p < 0.05). In the in vivo group 4 patients retained the bypass tube for 3 months or more; total lung capacity was reduced, and the forced expiratory volume in 1 second increased by 23% (mean percent predicted at baseline versus 3 months, 24.4% versus 29.5%).
  
  
  CONCLUSIONS
  An extrapulmonary airway bypass increases expiratory flow in emphysema. This may be a useful approach in hyperinflated patients with homogeneous emphysema.
authors.affiliation: Department of Respiratory Medicine, Royal Brompton and Harefield NHS Trust, London, United Kingdom.
authors.forename: Alastair J
authors.initials: AJ
authors.lastname: Moore
authors.forename: Edward
authors.initials: E
authors.lastname: Cetti
authors.forename: Saleem
authors.initials: S
authors.lastname: Haj-Yahia
authors.forename: Martin
authors.initials: M
authors.lastname: Carby
authors.forename: Gunilla
authors.initials: G
authors.lastname: Björling
authors.forename: Sigbritt
authors.initials: S
authors.lastname: Karlsson
authors.forename: Pallav
authors.initials: P
authors.lastname: Shah
authors.forename: Peter
authors.initials: P
authors.lastname: Goldstraw
authors.forename: John
authors.initials: J
authors.lastname: Moxham
authors.forename: Simon
authors.initials: S
authors.lastname: Jordan
authors.forename: Michael I
authors.initials: MI
authors.lastname: Polkey
mesh_terms: D000368:Aged; D015505:Chest Tubes; D004417:Dyspnea / Q000209:etiology / Q000503:physiopathology; D005260:Female; D005541:Forced Expiratory Volume; D006801:Humans; D066298:In Vitro Techniques; D008297:Male; D008875:Middle Aged; D019736:Prostheses and Implants; D011656:Pulmonary Emphysema / Q000503:physiopathology / Q000601:surgery*; D011658:Pulmonary Fibrosis / Q000503:physiopathology / Q000601:surgery; D012123:Pulmonary Ventilation; D012115:Residual Volume; D014109:Total Lung Capacity; D014797:Vital Capacity