title: Effects of nasal positive expiratory pressure on dynamic hyperinflation and 6-minute walk test in patients with COPD.
abstract: BACKGROUND
  Dynamic hyperinflation is an important target in the treatment of COPD. There is increasing evidence that positive expiratory pressure (PEP) could reduce dynamic hyperinflation during exercise. PEP application through a nasal mask and a flow resistance device might have the potential to be used during daily physical activities as an auxiliary strategy of ventilatory assistance. The aim of this study was to determine the effects of nasal PEP on lung volumes during physical exercise in patients with COPD.
  
  
  METHODS
  Twenty subjects (mean ± SD age 69.4 ± 6.4 years) with stable mild-to-severe COPD were randomized to undergo physical exercise with nasal PEP breathing, followed by physical exercise with habitual breathing, or vice versa. Physical exercise was induced by a standard 6-min walk test (6 MWT) protocol. PEP was applied by means of a silicone nasal mask loaded with a fixed-orifice flow resistor. Body plethysmography was performed immediately pre-exercise and post-exercise.
  
  
  RESULTS
  Differences in mean pre- to post-exercise changes in total lung capacity (-0.63 ± 0.80 L, P = .002), functional residual capacity (-0.48 ± 0.86 L, P = .021), residual volume (-0.56 ± 0.75 L, P = .004), S(pO2) (-1.7 ± 3.4%, P = .041), and 6 MWT distance (-30.8 ± 30.0 m, P = .001) were statistically significant between the experimental and the control interventions.
  
  
  CONCLUSIONS
  The use of flow-dependent expiratory pressure, applied with a nasal mask and a PEP device, might promote significant reduction of dynamic hyperinflation during walking exercise. Further studies are warranted addressing improvements in endurance performance under regular application of nasal PEP during physical activities.
authors.affiliation: Department of Internal Medicine II, University Hospital of Ulm, Ulm, Germany.
authors.forename: Thomas
authors.initials: T
authors.lastname: Wibmer
authors.forename: Stefan
authors.initials: S
authors.lastname: Rüdiger
authors.forename: Claudia
authors.initials: C
authors.lastname: Heitner
authors.forename: Cornelia
authors.initials: C
authors.lastname: Kropf-Sanchen
authors.forename: Ioanna
authors.initials: I
authors.lastname: Blanta
authors.forename: Kathrin M
authors.initials: KM
authors.lastname: Stoiber
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Rottbauer
authors.forename: Christian
authors.initials: C
authors.lastname: Schumann
mesh_terms: D000368:Aged; D018592:Cross-Over Studies; D005080:Exercise Test; D005260:Female; D006801:Humans; D008297:Male; D008397:Masks; D008875:Middle Aged; D009666:Nose; D010100:Oxygen / Q000097:blood; D010993:Plethysmography, Whole Body; D011175:Positive-Pressure Respiration / Q000295:instrumentation; D029424:Pulmonary Disease, Chronic Obstructive / Q000503:physiopathology* / Q000628:therapy*; D012115:Residual Volume; D016138:Walking / Q000502:physiology*
chemical_list: D010100:Oxygen
keywords: airway resistance; chronic obstructive pulmonary disease; dyspnea; lung capacities; positive-pressure respiration; respiration