title: Prolonged recruitment manoeuvre improves lung function with less ultrastructural damage in experimental mild acute lung injury.
abstract: The effects of prolonged recruitment manoeuvre (PRM) were compared with sustained inflation (SI) in paraquat-induced mild acute lung injury (ALI) in rats. Twenty-four hours after ALI induction, rats were anesthetized and mechanically ventilated with VT=6 ml/kg and positive end-expiratory pressure (PEEP)=5 cmH(2)O for 1h. SI was performed with an instantaneous pressure increase of 40 cmH(2)O that was sustained for 40s, while PRM was done by a step-wise increase in positive inspiratory pressure (PIP) of 15-20-25 cmH(2)O above a PEEP of 15 cm H(2)O (maximal PIP=40 cmH(2)O), with interposed periods of PIP=10 cmH(2)O above a PEEP=15 cmH(2)O. Lung static elastance and the amount of alveolar collapse were more reduced with PRM than SI, yielding improved oxygenation. Additionally, tumour necrosis factor-alpha, interleukin-6, interferon-gamma, and type III procollagen mRNA expressions in lung tissue and lung epithelial cell apoptosis decreased more in PRM. In conclusion, PRM improved lung function, with less damage to alveolar epithelium, resulting in reduced pulmonary injury.
authors.affiliation: Laboratory of Pulmonary Investigation, Carlos Chagas Filho Institute of Biophysics, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil.
authors.forename: Andréia F
authors.initials: AF
authors.lastname: Rzezinski
authors.forename: Gisele P
authors.initials: GP
authors.lastname: Oliveira
authors.forename: Viviane R
authors.initials: VR
authors.lastname: Santiago
authors.forename: Raquel S
authors.initials: RS
authors.lastname: Santos
authors.forename: Debora S
authors.initials: DS
authors.lastname: Ornellas
authors.forename: Marcelo M
authors.initials: MM
authors.lastname: Morales
authors.forename: Vera L
authors.initials: VL
authors.lastname: Capelozzi
authors.forename: Marcelo B P
authors.initials: MB
authors.lastname: Amato
authors.forename: Marcus B
authors.initials: MB
authors.lastname: Conde
authors.forename: Paolo
authors.initials: P
authors.lastname: Pelosi
authors.forename: Patricia R M
authors.initials: PR
authors.lastname: Rocco
mesh_terms: D055371:Acute Lung Injury / Q000473:pathology / Q000503:physiopathology* / Q000628:therapy*; D000818:Animals; D017209:Apoptosis / Q000502:physiology; D024061:Collagen Type III / Q000235:genetics / Q000378:metabolism; D016207:Cytokines / Q000235:genetics / Q000378:metabolism; D004195:Disease Models, Animal; D005786:Gene Expression Regulation / Q000502:physiology; D020287:In Situ Nick-End Labeling / Q000379:methods; D008168:Lung / Q000378:metabolism / Q000473:pathology* / Q000648:ultrastructure*; D008176:Lung Volume Measurements; D046529:Microscopy, Electron, Transmission / Q000379:methods; D011175:Positive-Pressure Respiration / Q000379:methods*; D012333:RNA, Messenger / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D012129:Respiratory Function Tests / Q000379:methods; D015656:Respiratory Mechanics / Q000502:physiology*; D018709:Statistics, Nonparametric
chemical_list: D024061:Collagen Type III; D016207:Cytokines; D012333:RNA, Messenger