title: Effects of ultraprotective ventilation, extracorporeal carbon dioxide removal, and spontaneous breathing on lung morphofunction and inflammation in experimental severe acute respiratory distress syndrome.
abstract: BACKGROUND
  To investigate the role of ultraprotective mechanical ventilation (UP-MV) and extracorporeal carbon dioxide removal with and without spontaneous breathing (SB) to improve respiratory function and lung protection in experimental severe acute respiratory distress syndrome.
  
  
  METHODS
  Severe acute respiratory distress syndrome was induced by saline lung lavage and mechanical ventilation (MV) with higher tidal volume (VT) in 28 anesthetized pigs (32.8 to 52.5 kg). Animals (n = 7 per group) were randomly assigned to 6 h of MV (airway pressure release ventilation) with: (1) conventional P-MV with VT ≈6 ml/kg (P-MVcontr); (2) UP-MV with VT ≈3 ml/kg (UP-MVcontr); (3) UP-MV with VT ≈3 ml/kg and SB (UP-MVspont); and (4) UP-MV with VT ≈3 ml/kg and pressure supported SB (UP-MVPS). In UP-MV groups, extracorporeal carbon dioxide removal was used.
  
  
  RESULTS
  The authors found that: (1) UP-MVcontr reduced diffuse alveolar damage score in dorsal lung zones (median[interquartile]) (12.0 [7.0 to 16.8] vs. 22.5 [13.8 to 40.8]), but worsened oxygenation and intrapulmonary shunt, compared to P-MVcontr; (2) UP-MVspont and UP-MVPS improved oxygenation and intrapulmonary shunt, and redistributed ventilation towards dorsal areas, as compared to UP-MVcontr; (3) compared to P-MVcontr, UP-MVcontr and UP-MVspont, UP-MVPS yielded higher levels of tumor necrosis factor-α (6.9 [6.5 to 10.1] vs. 2.8 [2.2 to 3.0], 3.6 [3.0 to 4.7] and 4.0 [2.8 to 4.4] pg/mg, respectively) and interleukin-8 (216.8 [113.5 to 343.5] vs. 59.8 [45.3 to 66.7], 37.6 [18.8 to 52.0], and 59.5 [36.1 to 79.7] pg/mg, respectively) in dorsal lung zones.
  
  
  CONCLUSIONS
  In this model of severe acute respiratory distress syndrome, MV with VT ≈3 ml/kg and extracorporeal carbon dioxide removal without SB slightly reduced lung histologic damage, but not inflammation, as compared to MV with VT = 4 to 6 ml/kg. During UP-MV, pressure supported SB increased lung inflammation.
authors.affiliation: From the Department of Anesthesiology and Intensive Care Medicine, Pulmonary Engineering Group, University Hospital Dresden, Technische Universität Dresden, Dresden, Germany (A.G., T. Kiss, T.B., C.U., A.B., N.C., T.Q., I.R., R.H., P.S., T.R., T. Koch, M.G.d.A.); Laboratory of Pulmonary Investigations, Carlos Chagas Filho Institute of Biophysics, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil (F.S., P.R.M.R.); Department of Anatomy, Medical Faculty Carl Gustav Carus, Technische Universität Dresden, Dresden, Germany (M.K.); and IRCCS San Martino IST Hospital, Department of Surgical Sciences and Integrated Diagnostics, University of Genoa, Genoa, Italy (P.P.).
authors.forename: Andreas
authors.initials: A
authors.lastname: Güldner
authors.forename: Thomas
authors.initials: T
authors.lastname: Kiss
authors.forename: Thomas
authors.initials: T
authors.lastname: Bluth
authors.forename: Christopher
authors.initials: C
authors.lastname: Uhlig
authors.forename: Anja
authors.initials: A
authors.lastname: Braune
authors.forename: Nadja
authors.initials: N
authors.lastname: Carvalho
authors.forename: Theresa
authors.initials: T
authors.lastname: Quast
authors.forename: Ines
authors.initials: I
authors.lastname: Rentzsch
authors.forename: Robert
authors.initials: R
authors.lastname: Huhle
authors.forename: Peter
authors.initials: P
authors.lastname: Spieth
authors.forename: Torsten
authors.initials: T
authors.lastname: Richter
authors.forename: Felipe
authors.initials: F
authors.lastname: Saddy
authors.forename: Patricia R M
authors.initials: PR
authors.lastname: Rocco
authors.forename: Michael
authors.initials: M
authors.lastname: Kasper
authors.forename: Thea
authors.initials: T
authors.lastname: Koch
authors.forename: Paolo
authors.initials: P
authors.lastname: Pelosi
authors.forename: Marcelo Gama
authors.initials: MG
authors.lastname: de Abreu
mesh_terms: D000818:Animals; D002245:Carbon Dioxide / Q000378:metabolism*; D015199:Extracorporeal Membrane Oxygenation / Q000379:methods*; D008168:Lung / Q000473:pathology / Q000502:physiology*; D011446:Prospective Studies; D011897:Random Allocation; D012121:Respiration, Artificial / Q000379:methods*; D012128:Respiratory Distress Syndrome / Q000378:metabolism* / Q000473:pathology / Q000628:therapy*; D015656:Respiratory Mechanics / Q000502:physiology; D013552:Swine; D016896:Treatment Outcome
chemical_list: D002245:Carbon Dioxide