title: Mechanical Power and Development of Ventilator-induced Lung Injury.
abstract: BACKGROUND
  The ventilator works mechanically on the lung parenchyma. The authors set out to obtain the proof of concept that ventilator-induced lung injury (VILI) depends on the mechanical power applied to the lung.
  
  
  METHODS
  Mechanical power was defined as the function of transpulmonary pressure, tidal volume (TV), and respiratory rate. Three piglets were ventilated with a mechanical power known to be lethal (TV, 38 ml/kg; plateau pressure, 27 cm H2O; and respiratory rate, 15 breaths/min). Other groups (three piglets each) were ventilated with the same TV per kilogram and transpulmonary pressure but at the respiratory rates of 12, 9, 6, and 3 breaths/min. The authors identified a mechanical power threshold for VILI and did nine additional experiments at the respiratory rate of 35 breaths/min and mechanical power below (TV 11 ml/kg) and above (TV 22 ml/kg) the threshold.
  
  
  RESULTS
  In the 15 experiments to detect the threshold for VILI, up to a mechanical power of approximately 12 J/min (respiratory rate, 9 breaths/min), the computed tomography scans showed mostly isolated densities, whereas at the mechanical power above approximately 12 J/min, all piglets developed whole-lung edema. In the nine confirmatory experiments, the five piglets ventilated above the power threshold developed VILI, but the four piglets ventilated below did not. By grouping all 24 piglets, the authors found a significant relationship between the mechanical power applied to the lung and the increase in lung weight (r = 0.41, P = 0.001) and lung elastance (r = 0.33, P < 0.01) and decrease in PaO2/FIO2 (r = 0.40, P < 0.001) at the end of the study.
  
  
  CONCLUSIONS
  In piglets, VILI develops if a mechanical power threshold is exceeded.
authors.affiliation: From the Dipartimento di Fisiopatologia Medico-Chirurgica e dei Trapianti, Fondazione IRCCS Ca' Granda-Ospedale Maggiore Policlinico, Università degli Studi di Milano, Milan, Italy (M.C., M.G., C.C., D.M., I.A., M.A., A.C., M.B., C.M., K.N., M.G., G.L.V., P.P., P.C.); Centro di Ricerche Precliniche, Fondazione IRCCS Ca' Granda-Ospedale Maggiore Policlinico, Milan, Italy (D.D., S.G.); Department of Anesthesiology and Intensive Care Medicine, Georg-August-University Goettingen, Goettingen, Germany (L.G.); and Dipartimento di Scienze Biomediche per la Salute, Università degli Studi di Milano, Milan, Italy (V.V., N.G.).
authors.forename: Massimo
authors.initials: M
authors.lastname: Cressoni
authors.forename: Miriam
authors.initials: M
authors.lastname: Gotti
authors.forename: Chiara
authors.initials: C
authors.lastname: Chiurazzi
authors.forename: Dario
authors.initials: D
authors.lastname: Massari
authors.forename: Ilaria
authors.initials: I
authors.lastname: Algieri
authors.forename: Martina
authors.initials: M
authors.lastname: Amini
authors.forename: Antonio
authors.initials: A
authors.lastname: Cammaroto
authors.forename: Matteo
authors.initials: M
authors.lastname: Brioni
authors.forename: Claudia
authors.initials: C
authors.lastname: Montaruli
authors.forename: Klodiana
authors.initials: K
authors.lastname: Nikolla
authors.forename: Mariateresa
authors.initials: M
authors.lastname: Guanziroli
authors.forename: Daniele
authors.initials: D
authors.lastname: Dondossola
authors.forename: Stefano
authors.initials: S
authors.lastname: Gatti
authors.forename: Vincenza
authors.initials: V
authors.lastname: Valerio
authors.forename: Giordano Luca
authors.initials: GL
authors.lastname: Vergani
authors.forename: Paola
authors.initials: P
authors.lastname: Pugni
authors.forename: Paolo
authors.initials: P
authors.lastname: Cadringher
authors.forename: Nicoletta
authors.initials: N
authors.lastname: Gagliano
authors.forename: Luciano
authors.initials: L
authors.lastname: Gattinoni
mesh_terms: D000399:Air Pressure; D000818:Animals; D004548:Elasticity; D004867:Equipment Design; D007320:Inspiratory Capacity; D008168:Lung / Q000000981:diagnostic imaging / Q000473:pathology / Q000503:physiopathology; D055595:Mechanical Phenomena; D009929:Organ Size; D011654:Pulmonary Edema / Q000139:chemically induced / Q000473:pathology; D011859:Radiography; D056152:Respiratory Rate; D034421:Sus scrofa; D055397:Ventilator-Induced Lung Injury / Q000473:pathology / Q000503:physiopathology*; D012122:Ventilators, Mechanical