title: Air Stacking: A Detailed Look Into Physiological Acute Effects on Cough Peak Flow and Chest Wall Volumes of Healthy Subjects.
abstract: BACKGROUND
  Air stacking (AS) is a lung insufflation method that requires the use of a manual insufflator to provide air volumes higher than inspiratory capacity. Neuromuscular patients benefit the most from the maneuver; however, the acute effects of AS in healthy subjects are still unclear.
  
  
  METHODS
  Twenty healthy subjects (8 males) were studied by optoelectronic plethysmography to investigate the immediate effects of AS on cough peak flow, operational volume variations, distribution of these volumes in the chest wall compartments (pulmonary rib cage, abdominal rib cage, and abdominal), breathing pattern, and shortening velocity of the respiratory muscles during a protocol that included vital capacity maneuvers and spontaneous coughs before and after AS.
  
  
  RESULTS
  Statistically significant increases in cough peak flow (P< .03) and inspiratory capacity (P< .001) were found immediately after AS. During its application, the pulmonary rib cage compartment was the largest contributor (P= .002) to chest wall volume displacement. A significant increase in chest wall tidal volume (P< .001), mainly in the pulmonary rib cage (P< .001), was observed. Significant increases (P< .001) in end-inspiratory chest wall volume were observed with main distribution in pulmonary (P< .001) and abdominal rib cage (P= .01). Significant increases in shortening velocity index of inspiratory muscles (P< .001), expiratory muscles (P< .001), and diaphragm (P< .001) were also observed. In addition, significant decreases in expiratory time (P< .001) and increases in duty cycle (P= .02), breathing frequency (P= .02), minute ventilation (P< .001), maximum inspiratory (P< .001), and expiratory flow (P< .001) were observed.
  
  
  CONCLUSIONS
  In healthy subjects, cough peak flow and chest wall volumes can be increased immediately after the application of the AS maneuver.
authors.affiliation: PneumoCardioVascular Lab, Hospital Universitário Onofre Lopes, Empresa Brasileira de Serviços Hospitalares (EBSERH), Universidade Federal do Rio Grande do Norte (UFRN), Natal RN, Brazil and the Laboratório de Desempenho PneumoCardioVascular & Músculos Respiratórios, Departamento de Fisioterapia, Universidade Federal do Rio Grande do Norte, UFRN, Natal RN, Brazil.
authors.forename: Antonio
authors.initials: A
authors.lastname: Sarmento
authors.affiliation: Departamento de Fisioterapia, Universidade Federal de Pernambuco, Recife PE, Brasil.
authors.forename: Armèle F Dornelas
authors.initials: AF
authors.lastname: de Andrade
authors.affiliation: PneumoCardioVascular Lab, Hospital Universitário Onofre Lopes, Empresa Brasileira de Serviços Hospitalares (EBSERH), Universidade Federal do Rio Grande do Norte (UFRN), Natal RN, Brazil and the Laboratório de Desempenho PneumoCardioVascular & Músculos Respiratórios, Departamento de Fisioterapia, Universidade Federal do Rio Grande do Norte, UFRN, Natal RN, Brazil.
authors.forename: Íllia Nadinne Df
authors.initials: ÍN
authors.lastname: Lima
authors.affiliation: Dipartimento di Elettronica, Informazione e Bioingegneria Politecnico di Milano, Milan, Italy.
authors.forename: Andrea
authors.initials: A
authors.lastname: Aliverti
authors.affiliation: PneumoCardioVascular Lab, Hospital Universitário Onofre Lopes, Empresa Brasileira de Serviços Hospitalares (EBSERH), Universidade Federal do Rio Grande do Norte (UFRN), Natal RN, Brazil and the Laboratório de Desempenho PneumoCardioVascular & Músculos Respiratórios, Departamento de Fisioterapia, Universidade Federal do Rio Grande do Norte, UFRN, Natal RN, Brazil.
authors.forename: Guilherme Augusto
authors.initials: GA
authors.lastname: de Freitas Fregonezi
authors.affiliation: PneumoCardioVascular Lab, Hospital Universitário Onofre Lopes, Empresa Brasileira de Serviços Hospitalares (EBSERH), Universidade Federal do Rio Grande do Norte (UFRN), Natal RN, Brazil and the Laboratório de Desempenho PneumoCardioVascular & Músculos Respiratórios, Departamento de Fisioterapia, Universidade Federal do Rio Grande do Norte, UFRN, Natal RN, Brazil. vanessaresqueti@hotmail.com.
authors.forename: Vanessa R
authors.initials: VR
authors.lastname: Resqueti
mesh_terms: D000328:Adult; D003371:Cough / Q000209:etiology / Q000503:physiopathology*; D005260:Female; D064368:Healthy Volunteers; D006801:Humans; D007320:Inspiratory Capacity; D008176:Lung Volume Measurements / Q000379:methods; D008297:Male; D010366:Peak Expiratory Flow Rate; D010991:Plethysmography / Q000379:methods; D012121:Respiration, Artificial / Q000009:adverse effects* / Q000379:methods; D012132:Respiratory Muscles / Q000503:physiopathology; D035441:Thoracic Wall / Q000503:physiopathology*; D055815:Young Adult
keywords: air stacking; chest wall volumes; cough peak flow; pulmonary expansion and optoelectronic plethysmography