title: Volume rather than flow incentive spirometry is effective in improving chest wall expansion and abdominal displacement using optoelectronic plethysmography.
abstract: BACKGROUND
  Incentive spirometers are widely used in clinical practice and classified as flow-oriented (FIS) and volume-oriented (VIS). Until recently the respiratory inductive plethysmography used to evaluate the effects of incentive spirometry on chest wall mechanics presented limitations, which may explain why the impact of VIS and FIS remains poorly known.
  
  
  OBJECTIVE
  To compare the effects of VIS and FIS on thoracoabdominal mechanics and respiratory muscle activity in healthy volunteers.
  
  
  METHODS
  This cross-sectional trial assessed 20 subjects (12 female, ages 20-40 years, body mass index 20-30 kg/m(2)). All subjects performed 8 quiet breaths and 8 deep breaths with FIS and VIS, in a randomized order. We measured thoracoabdominal chest wall, upper and lower rib-cage, and abdominal volumes with optoelectronic plethysmography, and the muscle activity of the sternocleidomastoid and superior and inferior intercostal muscles with electromyography.
  
  
  RESULTS
  VIS increased chest wall volume more than did FIS (P = .007) and induced a larger increase in the upper and lower rib-cages and abdomen (156%, 91%, and 151%, respectively, P < .001). By contrast, FIS induced more activity in the accessory muscles of respiration than did VIS (P < .001).
  
  
  CONCLUSIONS
  VIS promotes a greater increase in chest wall volume, with a larger abdominal contribution and lower respiratory muscle activity, than does FIS in healthy adults.
authors.affiliation: Department of Physical Therapy, School of Medicine, University of São Paulo, São Paulo, Brazil.
authors.forename: Denise de Moraes
authors.initials: Dde M
authors.lastname: Paisani
authors.forename: Adriana Claudia
authors.initials: AC
authors.lastname: Lunardi
authors.forename: Cibele Cristine Berto Marques
authors.initials: CC
authors.lastname: da Silva
authors.forename: Desiderio Cano
authors.initials: DC
authors.lastname: Porras
authors.forename: Clarice
authors.initials: C
authors.lastname: Tanaka
authors.forename: Celso Ricardo Fernandes
authors.initials: CR
authors.lastname: Carvalho
mesh_terms: D000009:Abdominal Muscles / Q000502:physiology; D000328:Adult; D003430:Cross-Sectional Studies; D004576:Electromyography; D005260:Female; D006801:Humans; D008297:Male; D010991:Plethysmography; D015656:Respiratory Mechanics / Q000502:physiology*; D012132:Respiratory Muscles / Q000502:physiology*; D013147:Spirometry / Q000379:methods*; D035441:Thoracic Wall / Q000502:physiology*; D055815:Young Adult