title: Improvement after lung volume reduction surgery: a role for inspiratory muscle adaptation.
abstract: In severe emphysema, lung volume reduction surgery (LVRS) can improve lung function and exercise tolerance. The maximal changes of forced expiratory volume in 1s (FEV(1)) and lung volume occur early after surgery, whereas maximal improvement of exercise tolerance occurs later. We tested the hypothesis that secondary adaptation of inspiratory muscles could explain this delayed clinical improvement. In that purpose, we evaluated nine consecutive patients before LVRS and up to 9 months post-operatively. Six weeks after LVRS, we observed an increase in FEV(1) and 6 min walk distance (6MWD). The gain in sniff nasal inspiratory pressure (SNIP) was inversely proportional to lung volume loss. Values of FEV(1) and lung volume were maintained throughout follow-up whereas SNIP values significantly increased from 6 weeks to 6 months post-LVRS. In the meantime, we observed an increase in 6MWD correlated with the SNIP increase. This suggests that in patients undergoing LVRS, early improvement of SNIP is proportional to decrease in lung volume whereas the further delayed improvement may be due, at least in part, to adaptation of the inspiratory muscles.
authors.affiliation: Service de Pneumologie, CHU Purpan, TSA 40031, 31059 Toulouse Cedex 9, France. degano.b@chu-toulouse.fr
authors.forename: Bruno
authors.initials: B
authors.lastname: Degano
authors.forename: Laurent
authors.initials: L
authors.lastname: Brouchet
authors.forename: Jacques
authors.initials: J
authors.lastname: Rami
authors.forename: Jean-François
authors.initials: JF
authors.lastname: Arnal
authors.forename: Roger
authors.initials: R
authors.lastname: Escamilla
authors.forename: Christophe
authors.initials: C
authors.lastname: Hermant
authors.forename: Marcel
authors.initials: M
authors.lastname: Dahan
mesh_terms: D000328:Adult; D000368:Aged; D003964:Diaphragm / Q000473:pathology / Q000503:physiopathology; D004417:Dyspnea / Q000503:physiopathology; D004646:Emphysema / Q000601:surgery*; D017079:Exercise Tolerance / Q000502:physiology*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D001239:Inhalation / Q000502:physiology; D008297:Male; D008875:Middle Aged; D011013:Pneumonectomy / Q000379:methods*; D011446:Prospective Studies; D011788:Quality of Life; D012129:Respiratory Function Tests / Q000379:methods; D012132:Respiratory Muscles / Q000503:physiopathology*; D013997:Time Factors; D014109:Total Lung Capacity / Q000502:physiology*