title: Effects of recruitment maneuvers with PEEP on lung volume distribution in canine models of direct and indirect lung injury.
abstract: Lung recruitment maneuvers can help open collapsed lung units for sufficient oxygenation, and positive end expiratory pressure (PEEP) is used to keep the lung open after recruitment. However, the application of high PEEP levels may play a significant role in causing regional lung hyperinflation during mechanical ventilation. The authors sought to study the effects of PEEP targeting optimal oxygenation on regional lung volume distribution in a direct and an indirect acute respiratory distress syndrome (ARDS) model. ARDS was induced by either surfactant depletion or oleic acid injection in dogs. After lung recruitment, PEEP was decreased from 20 to 10 cmH2O in 2 cmH2O steps every 10 min to examine regional lung aeration by using computed tomography. Lung injury appeared to be localized in the model of surfactant depletion while it widely diffused after oleic acid infusion. At PEEP levels that achieved optimal oxygenation, nonaerated lung units decreased and normally aerated lung units enhanced, but hyperinflated areas increased significantly in both models (P < 0.05). Hyperinflated areas were greater in the surfactant depletion model than in the oleic acid model at PEEP levels applied (P < 0.05). Optimal oxygenation guided PEEP may cause hyperinflated in both focal lung injury and diffused lung injury post lung recruitment. Hyperinflation was more susceptible in focal lung injury than in diffused lung injury post lung recruitment.
authors.affiliation: Department of Critical Care Medicine, Nanjing Zhong-Da Hospital, Southeast University, 87 Dingjiaqiao Rd, Nanjing, 210009, People's Republic of China.
authors.forename: Yi
authors.initials: Y
authors.lastname: Yang
authors.forename: Qiuhua
authors.initials: Q
authors.lastname: Chen
authors.forename: Songqiao
authors.initials: S
authors.lastname: Liu
authors.forename: Yingzi
authors.initials: Y
authors.lastname: Huang
authors.forename: Ling
authors.initials: L
authors.lastname: Liu
authors.forename: Xiaoyan
authors.initials: X
authors.lastname: Wu
authors.forename: Guangjian
authors.initials: G
authors.lastname: Chen
authors.forename: Jiyang
authors.initials: J
authors.lastname: Jin
authors.forename: Gaojun
authors.initials: G
authors.lastname: Teng
authors.forename: Haibo
authors.initials: H
authors.lastname: Qiu
mesh_terms: D000818:Animals; D004285:Dogs; D006801:Humans; D055370:Lung Injury / Q000188:drug therapy / Q000503:physiopathology*; D019301:Oleic Acid / Q000008:administration & dosage; D011175:Positive-Pressure Respiration; D012128:Respiratory Distress Syndrome / Q000503:physiopathology* / Q000628:therapy; D014057:Tomography, X-Ray Computed
chemical_list: D019301:Oleic Acid