title: Manual vibration increases expiratory flow rate via increased intrapleural pressure in healthy adults: an experimental study.
abstract: OBJECTIVE
  What is the relationship between vibration of the chest wall and the resulting chest wall force, chest wall circumference,intrapleural pressure, and expiratory flow rate? Is the change in intrapleural pressure during vibration the sum of the intrapleural pressure due to recoil of the lung, chest wall compression, and chest wall oscillation?
  
  
  METHODS
  Randomised, within-subject,experimental study.
  
  
  METHODS
  Seven experienced cardiopulmonary physiotherapists and three healthy adults.
  
  
  METHODS
  Vibration (compression + oscillation), compression alone, and oscillation alone were applied manually to the chest walls of healthy participants during passive exertion and compared with passive expiration alone.
  
  
  METHODS
  Chest wall force, chest wall circumference, intrapleural pressure, and expiratory flow rate.
  
  
  RESULTS
  During vibration, coherence was high(r2 > 0.97) between external chest wall force, chest wall circumference, intrapleural pressure, and expiratory flow. The mean change in intrapleural pressure during vibration was 9.55 cmH2O (SD 1.66), during chest compression alone was 8.06 cmH2O(SD 1.65), during oscillation alone was 7.93 cmH2O (SD 1.57), and during passive expiration alone was 6.82 cmH2O (SD 1.51). During vibration, compression contributed 13% of the change in intrapleural pressure, oscillation contributed 12%, and lung recoil contributed the remaining 75%.
  
  
  CONCLUSIONS
  During vibration the chest behaves as a highly linear system. Changes in intrapleural pressure occurring during vibration appear to be the sum of changes in pressure due to lung recoil and the compressive and oscillatory components of the technique, which suggests that all three components are required to optimise expiratory flow.
authors.affiliation: Faculty of Health Sciences, The University of Sydney, Lidcombe, NSW 1825, Australia. B.Mccarren@fhs.usyd.edu.au
authors.forename: Bredge
authors.initials: B
authors.lastname: McCarren
authors.forename: Jennifer A
authors.initials: JA
authors.lastname: Alison
authors.forename: Robert D
authors.initials: RD
authors.lastname: Herbert
mesh_terms: D000328:Adult; D035641:Chest Wall Oscillation / Q000379:methods; D045853:Exhalation / Q000502:physiology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D026201:Musculoskeletal Manipulations / Q000379:methods*; D010366:Peak Expiratory Flow Rate / Q000502:physiology; D026741:Physical Therapy Modalities; D035422:Pleural Cavity / Q000502:physiology*; D015656:Respiratory Mechanics / Q000502:physiology; D012143:Respiratory Physiological Phenomena; D035441:Thoracic Wall / Q000502:physiology*; D014732:Vibration