title: Volume-controlled Ventilation Does Not Prevent Injurious Inflation during Spontaneous Effort.
abstract: Spontaneous breathing during mechanical ventilation increases transpulmonary pressure and Vt, and worsens lung injury. Intuitively, controlling Vt and transpulmonary pressure might limit injury caused by added spontaneous effort.
  
  
  
  To test the hypothesis that, during spontaneous effort in injured lungs, limitation of Vt and transpulmonary pressure by volume-controlled ventilation results in less injurious patterns of inflation.
  
  
  
  Dynamic computed tomography was used to determine patterns of regional inflation in rabbits with injured lungs during volume-controlled or pressure-controlled ventilation. Transpulmonary pressure was estimated by using esophageal balloon manometry [Pl(es)] with and without spontaneous effort. Local dependent lung stress was estimated as the swing (inspiratory change) in transpulmonary pressure measured by intrapleural manometry in dependent lung and was compared with the swing in Pl(es). Electrical impedance tomography was performed to evaluate the inflation pattern in a larger animal (pig) and in a patient with acute respiratory distress syndrome.
  
  
  
  Spontaneous breathing in injured lungs increased Pl(es) during pressure-controlled (but not volume-controlled) ventilation, but the pattern of dependent lung inflation was the same in both modes. In volume-controlled ventilation, spontaneous effort caused greater inflation and tidal recruitment of dorsal regions (greater than twofold) compared with during muscle paralysis, despite the same Vt and Pl(es). This was caused by higher local dependent lung stress (measured by intrapleural manometry). In injured lungs, esophageal manometry underestimated local dependent pleural pressure changes during spontaneous effort.
  
  
  
  Limitation of Vt and Pl(es) by volume-controlled ventilation could not eliminate harm caused by spontaneous breathing unless the level of spontaneous effort was lowered and local dependent lung stress was reduced.
authors.affiliation: 1 Intensive Care Unit, Osaka University Hospital, Suita, Japan.|2 Translational Medicine, Department of Critical Care Medicine and Department of Anesthesia, Hospital for Sick Children, University of Toronto, Toronto, Ontario, Canada.
authors.forename: Takeshi
authors.initials: T
authors.lastname: Yoshida
authors.affiliation: 1 Intensive Care Unit, Osaka University Hospital, Suita, Japan.|3 Emergency and Critical Care Center, Mie University Hospital, Tsu, Japan.
authors.forename: Susumu
authors.initials: S
authors.lastname: Nakahashi
authors.affiliation: 4 Laboratório de Pneumologia LIM-09, Disciplina de Pneumologia, Instituto do Coração (Incor), Hospital das Clínicas da Faculdade de Medicina da Universidade de São Paulo, São Paulo, Brazil; and.
authors.forename: Maria Aparecida Miyuki
authors.initials: MAM
authors.lastname: Nakamura
authors.affiliation: 1 Intensive Care Unit, Osaka University Hospital, Suita, Japan.
authors.forename: Yukiko
authors.initials: Y
authors.lastname: Koyama
authors.affiliation: 4 Laboratório de Pneumologia LIM-09, Disciplina de Pneumologia, Instituto do Coração (Incor), Hospital das Clínicas da Faculdade de Medicina da Universidade de São Paulo, São Paulo, Brazil; and.|5 Unidad de Cuidados Intensivos, Hospital Rebagliati, Lima, Peru.
authors.forename: Rollin
authors.initials: R
authors.lastname: Roldan
authors.affiliation: 4 Laboratório de Pneumologia LIM-09, Disciplina de Pneumologia, Instituto do Coração (Incor), Hospital das Clínicas da Faculdade de Medicina da Universidade de São Paulo, São Paulo, Brazil; and.
authors.forename: Vinicius
authors.initials: V
authors.lastname: Torsani
authors.affiliation: 4 Laboratório de Pneumologia LIM-09, Disciplina de Pneumologia, Instituto do Coração (Incor), Hospital das Clínicas da Faculdade de Medicina da Universidade de São Paulo, São Paulo, Brazil; and.
authors.forename: Roberta R
authors.initials: RR
authors.lastname: De Santis
authors.affiliation: 4 Laboratório de Pneumologia LIM-09, Disciplina de Pneumologia, Instituto do Coração (Incor), Hospital das Clínicas da Faculdade de Medicina da Universidade de São Paulo, São Paulo, Brazil; and.
authors.forename: Susimeire
authors.initials: S
authors.lastname: Gomes
authors.affiliation: 1 Intensive Care Unit, Osaka University Hospital, Suita, Japan.
authors.forename: Akinori
authors.initials: A
authors.lastname: Uchiyama
authors.affiliation: 4 Laboratório de Pneumologia LIM-09, Disciplina de Pneumologia, Instituto do Coração (Incor), Hospital das Clínicas da Faculdade de Medicina da Universidade de São Paulo, São Paulo, Brazil; and.
authors.forename: Marcelo B P
authors.initials: MBP
authors.lastname: Amato
authors.affiliation: 2 Translational Medicine, Department of Critical Care Medicine and Department of Anesthesia, Hospital for Sick Children, University of Toronto, Toronto, Ontario, Canada.
authors.forename: Brian P
authors.initials: BP
authors.lastname: Kavanagh
authors.affiliation: 1 Intensive Care Unit, Osaka University Hospital, Suita, Japan.
authors.forename: Yuji
authors.initials: Y
authors.lastname: Fujino
mesh_terms: D000818:Animals; D004195:Disease Models, Animal; D006801:Humans; D055370:Lung Injury / Q000000981:diagnostic imaging / Q000209:etiology / Q000503:physiopathology*; D008297:Male; D011817:Rabbits; D012121:Respiration, Artificial / Q000009:adverse effects / Q000379:methods*; D015656:Respiratory Mechanics / Q000502:physiology*; D014057:Tomography, X-Ray Computed; D055397:Ventilator-Induced Lung Injury / Q000503:physiopathology*
keywords: acute respiratory distress syndrome; mechanical ventilation; spontaneous breathing