title: Lung mechanical changes following bronchoaspiration in a porcine model: differentiation of direct and indirect mechanisms.
abstract: Bronchoaspiration results in local deterioration of lung function through direct damage and/or indirect systemic effects related to neurohumoral pathways. We distinguished these effects by selectively intubating the two main bronchi in pigs while a PEEP of 4 or 10cm H2O was maintained. Gastric juice was instilled only into the right lung. Lung mechanical and ventilation defects were assessed by measuring unilateral pulmonary input impedance (ZL,s) and the third phase slope of the capnogram (SIII) for each lung side separately before the aspiration and for 120min thereafter. Marked transient elevations in ZL,s parameters and SIII were observed in the affected lung after aspiration. Elevating PEEP did not affect these responses in the ZL,s parameters, whereas it prevented the SIII increases. None of these indices changed in the intact left lung. These findings furnish evidence of the predominance of the local direct damage over the indirect systemic effects in the development of the deterioration of lung function, and demonstrate the benefit of an initially elevated PEEP following aspiration.
authors.affiliation: Department of Medical Physics and Informatics, University of Szeged, Szeged, Hungary.
authors.forename: Gergely H
authors.initials: GH
authors.lastname: Fodor
authors.affiliation: Department of Medical Physics and Informatics, University of Szeged, Szeged, Hungary. Electronic address: petak.ferenc@med.u-szeged.hu.
authors.forename: Ferenc
authors.initials: F
authors.lastname: Peták
authors.affiliation: Institute of Surgical Research, University of Szeged, Szeged, Hungary.
authors.forename: Dániel
authors.initials: D
authors.lastname: Erces
authors.affiliation: Department of Anaesthesiology and Intensive Therapy, University of Szeged, Szeged, Hungary.
authors.forename: Adám L
authors.initials: AL
authors.lastname: Balogh
authors.affiliation: Department of Anaesthesiology and Intensive Therapy, University of Szeged, Szeged, Hungary.
authors.forename: Barna
authors.initials: B
authors.lastname: Babik
mesh_terms: D000403:Airway Resistance; D000818:Animals; D001784:Blood Gas Analysis; D019296:Capnography; D004195:Disease Models, Animal; D005750:Gastric Juice; D006439:Hemodynamics; D007440:Intubation; D008168:Lung / Q000503:physiopathology*; D055370:Lung Injury / Q000209:etiology* / Q000503:physiopathology* / Q000628:therapy; D011175:Positive-Pressure Respiration; D012123:Pulmonary Ventilation; D012119:Respiration; D063466:Respiratory Aspiration of Gastric Contents / Q000503:physiopathology*; D015656:Respiratory Mechanics / Q000502:physiology*; D013552:Swine; D013556:Swine, Miniature
keywords: Acid aspiration; Capnography; Forced oscillations; Gastric content; Lung mechanics; Mechanical ventilation