title: Effects of pulmonary acid aspiration on the lungs and extra-pulmonary organs: a randomized study in pigs.
abstract: BACKGROUND
  There is mounting evidence that injury to one organ causes indirect damage to other organ systems with increased morbidity and mortality. The aim of this study was to determine the effects of acid aspiration pneumonitis (AAP) on extrapulmonary organs and to test the hypothesis that these could be due to circulatory depression or hypoxemia.
  
  
  METHODS
  Mechanically ventilated anesthetized pigs were randomized to receive intrabronchial instillation of hydrochloric acid (n = 7) or no treatment (n = 7). Hydrochloric acid (0.1 N, pH 1.1, 2.5 ml/kg BW) was instilled into the lungs during the inspiratory phase of ventilation. Hemodynamics, respiratory function and computer tomography (CT) scans of lung and brain were followed over a four-hour period. Tissue samples of lung, heart, liver, kidney and hippocampus were collected at the end of the experiment.
  
  
  RESULTS
  Acid instillation caused pulmonary edema, measured as increased extravascular lung water index (ELWI), impaired gas exchange and increased mean pulmonary artery pressure. Gas exchange tended to improve during the course of the study, despite increasing ELWI. In AAP animals compared to controls we found: a) cardiac leukocyte infiltration and necrosis in the conduction system and myocardium; b) lymphocyte infiltration in the liver, spreading from the periportal zone with prominent areas of necrosis; c) renal inflammation with lymphocyte infiltration, edema and necrosis in the proximal and distal tubules; and d) a tendency towards more severe hippocampal damage (P > 0.05).
  
  
  CONCLUSIONS
  Acid aspiration pneumonitis induces extrapulmonary organ injury. Circulatory depression and hypoxemia are unlikely causative factors. ELWI is a sensitive bedside parameter of early lung damage.
authors.affiliation: Department of Anaesthesiology, Emergency and Intensive Care Medicine, University of Göttingen Medical Center, Robert-Koch-Straße 40, 37075 Göttingen, Germany. jheuer@med.uni-goettingen.de
authors.forename: Jan Florian
authors.initials: JF
authors.lastname: Heuer
authors.forename: Philip
authors.initials: P
authors.lastname: Sauter
authors.forename: Paolo
authors.initials: P
authors.lastname: Pelosi
authors.forename: Peter
authors.initials: P
authors.lastname: Herrmann
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Brück
authors.forename: Christina
authors.initials: C
authors.lastname: Perske
authors.forename: Fritz
authors.initials: F
authors.lastname: Schöndube
authors.forename: Thomas A
authors.initials: TA
authors.lastname: Crozier
authors.forename: Annalen
authors.initials: A
authors.lastname: Bleckmann
authors.forename: Tim
authors.initials: T
authors.lastname: Beißbarth
authors.forename: Michael
authors.initials: M
authors.lastname: Quintel
mesh_terms: D000818:Animals; D015633:Extravascular Lung Water / Q000378:metabolism; D006329:Heart Conduction System / Q000503:physiopathology; D006439:Hemodynamics; D006624:Hippocampus / Q000503:physiopathology; D006851:Hydrochloric Acid; D007249:Inflammation / Q000503:physiopathology; D007668:Kidney / Q000503:physiopathology; D008099:Liver / Q000503:physiopathology; D011015:Pneumonia, Aspiration / Q000000981:diagnostic imaging / Q000503:physiopathology*; D011654:Pulmonary Edema / Q000209:etiology / Q000503:physiopathology; D011659:Pulmonary Gas Exchange; D011897:Random Allocation; D018709:Statistics, Nonparametric; D013552:Swine; D014057:Tomography, X-Ray Computed
chemical_list: D006851:Hydrochloric Acid