title: How much esophageal pressure-guided end-expiratory transpulmonary pressure is sufficient to maintain lung recruitment in lavage-induced lung injury?
abstract: BACKGROUND
  Because of limitations of the esophageal balloon technique, the value of using esophageal pressure (Pes)-guided end-expiratory transpulmonary pressure (PL-exp) to maintain lung recruitment in adult respiratory distress syndrome is controversial. This study aimed to investigate whether tailoring PL-exp to greater than 0 was enough to maintain lung recruitment.
  
  
  METHODS
  Ten pigs with severe lavage-induced lung injury were mechanically ventilated in a decremental positive end-expiratory pressure (PEEP) trial that was reduced from 20 to 6 cm H2O after full-lung recruitment. Respiratory mechanics, blood gases, hemodynamic data, and whole-lung computed tomography scans were recorded at each PEEP level. Open-lung PEEP (OL-PEEP) was determined by computed tomography, while Pes-guided PEEP (Pes-PEEP) was to maintain PL-exp greater than 0.
  
  
  RESULTS
  OL-PEEP was higher than Pes-PEEP, which induced a higher PL-exp at OL-PEEP than at Pes-PEEP (4.6 [1.6] cm H2O vs. 1.2 [0.6] cm H2O, p < 0.001). Compared with OL-PEEP, the nonaerated lung region was significantly increased at Pes-PEEP. Superimposed pressure (SP) of the lung tissue between the esophageal plane and the dorsal level was higher at Pes-PEEP than at OL-PEEP, whereas PL-exp at the dorsal level was lower at Pes-PEEP than at OL-PEEP (-1.5 [0.7] cm H2O vs. 2.5 [1.5] cm H2O, p < 0.001). The SP correlated with PL-exp at the dorsal level and the nonaerated lung region.
  
  
  CONCLUSIONS
  In this surfactant-depleted model, maintaining PL-exp just greater than 0 using Pes was unable to maintain lung recruitment; this was partly caused by a lack of compensation for the increased SP between the esophageal plane and the dorsal level.
authors.affiliation: From the Department of Critical Care Medicine (Y.H., R.T., Q.C., C.P., S.L., X.H., Y.L., Y.Y., H.Q.), Zhong-Da Hospital, School of Medicine, Southeast University, Nanjing; and Department of Critical Care Medicine (R.T.), The First Affiliated Hospital of Anhui Medical University, Hefei, China; and Dipartimento di Anestesiologia e Rianimazione (M.R.), Universita` di Torino, Ospedale S. Giovanni Battista-Molinette, Turin, Italy.
authors.forename: Yingzi
authors.initials: Y
authors.lastname: Huang
authors.forename: Rui
authors.initials: R
authors.lastname: Tang
authors.forename: Qiuhua
authors.initials: Q
authors.lastname: Chen
authors.forename: Chun
authors.initials: C
authors.lastname: Pan
authors.forename: Songqiao
authors.initials: S
authors.lastname: Liu
authors.forename: Xia
authors.initials: X
authors.lastname: Hui
authors.forename: Yang
authors.initials: Y
authors.lastname: Li
authors.forename: Yi
authors.initials: Y
authors.lastname: Yang
authors.forename: V Marco
authors.initials: VM
authors.lastname: Ranieri
authors.forename: Haibo
authors.initials: H
authors.lastname: Qiu
mesh_terms: D000818:Animals; D018893:Bronchoalveolar Lavage; D004195:Disease Models, Animal; D004947:Esophagus / Q000502:physiology*; D005260:Female; D055370:Lung Injury / Q000209:etiology / Q000503:physiopathology / Q000628:therapy*; D008297:Male; D011175:Positive-Pressure Respiration / Q000379:methods*; D011312:Pressure; D015656:Respiratory Mechanics / Q000502:physiology; D013552:Swine; D013990:Tidal Volume / Q000502:physiology