title: Effect of bronchoscopic lung volume reduction on dynamic hyperinflation and exercise in emphysema.
abstract: Endobronchial valve placement improves pulmonary function in some patients with chronic obstructive pulmonary disease, but its effects on exercise physiology have not been investigated. In 19 patients with a mean (SD) FEV(1) of 28.4 (11.9)% predicted, studied before and 4 weeks after unilateral valve insertion, functional residual capacity decreased from 7.1 (1.5) to 6.6 (1.7) L (p = 0.03) and diffusing capacity rose from 3.3 (1.1) to 3.7 (1.2) mmol . minute(-1) . kPa(-1) (p = 0.03). Cycle endurance time at 80% of peak workload increased from 227 (129) to 315 (195) seconds (p = 0.03). This was associated with a reduction in end-expiratory lung volume at peak exercise from 7.6 (1.6) to 7.2 (1.7) L (p = 0.03). Using stepwise logistic regression analysis, a model containing changes in transfer factor and resting inspiratory capacity explained 81% of the variation in change in exercise time (p < 0.0001). The same variables were retained if the five patients with radiologic atelectasis were excluded from analysis. In a subgroup of patients in whom invasive measurements were performed, improvement in exercise capacity was associated with a reduction in lung compliance (r(2) = 0.43; p = 0.03) and isotime esophageal pressure-time product (r(2) = 0.47; p = 0.03). Endobronchial valve placement can improve lung volumes and gas transfer in patients with chronic obstructive pulmonary disease and prolong exercise time by reducing dynamic hyperinflation.
authors.affiliation: Respiratory Muscle Laboratory, Department of Respiratory Medicine, Royal Brompton Hospital, Fulham Road, London SW3 6NP, UK. n.hopkinson@ic.ac.uk
authors.forename: Nicholas S
authors.initials: NS
authors.lastname: Hopkinson
authors.forename: Tudor P
authors.initials: TP
authors.lastname: Toma
authors.forename: David M
authors.initials: DM
authors.lastname: Hansell
authors.forename: Peter
authors.initials: P
authors.lastname: Goldstraw
authors.forename: John
authors.initials: J
authors.lastname: Moxham
authors.forename: Duncan M
authors.initials: DM
authors.lastname: Geddes
authors.forename: Michael I
authors.initials: MI
authors.lastname: Polkey
mesh_terms: D001999:Bronchoscopy / Q000379:methods*; D004646:Emphysema / Q000150:complications / Q000503:physiopathology* / Q000601:surgery*; D017079:Exercise Tolerance; D005260:Female; D006801:Humans; D008170:Lung Compliance; D008176:Lung Volume Measurements; D008297:Male; D008875:Middle Aged; D011013:Pneumonectomy / Q000379:methods*; D001261:Pulmonary Atelectasis / Q000209:etiology / Q000503:physiopathology / Q000601:surgery; D012132:Respiratory Muscles / Q000503:physiopathology; D016896:Treatment Outcome