title: Prone position prevents regional alveolar hyperinflation and mechanical stress and strain in mild experimental acute lung injury.
abstract: Prone position may delay the development of ventilator-induced lung injury (VILI), but the mechanisms require better elucidation. In experimental mild acute lung injury (ALI), arterial oxygen partial pressure (Pa O2), lung mechanics and histology, inflammatory markers [interleukin (IL)-6 and IL-1 beta], and type III procollagen (PCIII) mRNA expressions were analysed in supine and prone position. Wistar rats were randomly divided into two groups. In controls, saline was intraperitoneally injected while ALI was induced by paraquat. After 24-h, the animals were mechanically ventilated for 1-h in supine or prone positions. In ALI, prone position led to a better blood flow/tissue ratio both in ventral and dorsal regions and was associated with a more homogeneous distribution of alveolar aeration/tissue ratio reducing lung static elastance and viscoelastic pressure, and increasing end-expiratory lung volume and Pa O2. PCIII expression was higher in the ventral than dorsal region in supine position, with no regional changes in inflammatory markers. In conclusion, prone position may protect the lungs against VILI, thus reducing pulmonary stress and strain.
authors.affiliation: Laboratory of Pulmonary Investigation, Carlos Chagas Filho Biophysics Institute, Federal University of Rio de Janeiro, RJ, Brazil.
authors.forename: Maria Cristina E
authors.initials: MC
authors.lastname: Santana
authors.forename: Cristiane S N B
authors.initials: CS
authors.lastname: Garcia
authors.forename: Débora G
authors.initials: DG
authors.lastname: Xisto
authors.forename: Lilian K S
authors.initials: LK
authors.lastname: Nagato
authors.forename: Roberta M
authors.initials: RM
authors.lastname: Lassance
authors.forename: Luiz Felipe M
authors.initials: LF
authors.lastname: Prota
authors.forename: Felipe M
authors.initials: FM
authors.lastname: Ornellas
authors.forename: Vera L
authors.initials: VL
authors.lastname: Capelozzi
authors.forename: Marcelo M
authors.initials: MM
authors.lastname: Morales
authors.forename: Walter A
authors.initials: WA
authors.lastname: Zin
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 / Q000378:metabolism / Q000473:pathology / Q000503:physiopathology*; D000818:Animals; D005260:Female; D018836:Inflammation Mediators / Q000378:metabolism; D053583:Interleukin-1beta / Q000096:biosynthesis; D015850:Interleukin-6 / Q000096:biosynthesis; D010100:Oxygen; D010313:Partial Pressure; D011347:Procollagen / Q000096:biosynthesis; D016684:Prone Position / Q000502:physiology*; D011650:Pulmonary Alveoli / Q000503:physiopathology*; D012333:RNA, Messenger / Q000032:analysis; D051381:Rats; D017208:Rats, Wistar; D015656:Respiratory Mechanics / Q000502:physiology*; D014797:Vital Capacity / Q000502:physiology
chemical_list: D018836:Inflammation Mediators; D053583:Interleukin-1beta; D015850:Interleukin-6; D011347:Procollagen; D012333:RNA, Messenger; D010100:Oxygen