title: Early mechanical ventilation is deleterious after aspiration-induced lung injury in rabbits.
abstract: We investigated whether mechanical ventilation after aspiration is deleterious when started before surfactant therapy. Gas exchange and lung mechanics were measured in rabbits after aspiration either mechanically ventilated before or after lavage with diluted surfactant or Ringer's solution. Lung injury was induced by intratracheal instillation of 2 mL/kg of a betain/HCl pepsin mixture. After 30 min of spontaneous breathing, ventilation was started in 12 rabbits, which were then treated by lavage with diluted surfactant (15 mL/kg body weight; 5.3 mg/mL, group MVpre S) or with Ringer's solution (1 mL/kg; group MVpre R). Another 12 rabbits were treated by lavage while spontaneously breathing and were then connected to the ventilator (MVpost S and MVpost R). Sham control rabbits were mechanically ventilated for 4 h. At the end of experiment, PaO2/FiO2 ratio in MVpost S was five times higher than in MVpre S (P=0.0043). Lung mechanics measurements showed significant difference between MVpre S and MVpost S (P=0.0072). There was histopathologic evidence of decreased lung injury in MVpost S. Immediate initiation of ventilation is harmful when lung injury is induced by aspiration. Further investigations are needed to clarify whether the timing of lavage with diluted surfactant has an impact on the treatment of patients with aspiration or comparable types of direct lung injury.
authors.affiliation: Division of Neonatology and Pediatric Intensive Care, University Children's Hospital, Medical University of Vienna, Austria. michael.hermon@meduniwien.ac.at
authors.forename: Michael M
authors.initials: MM
authors.lastname: Hermon
authors.forename: Esther
authors.initials: E
authors.lastname: Wassermann
authors.forename: Claudia
authors.initials: C
authors.lastname: Pfeiler
authors.forename: Arnold
authors.initials: A
authors.lastname: Pollak
authors.forename: Heinz
authors.initials: H
authors.lastname: Redl
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Strohmaier
mesh_terms: D000818:Animals; D018893:Bronchoalveolar Lavage; D006439:Hemodynamics; D008168:Lung / Q000473:pathology*; D008171:Lung Diseases / Q000473:pathology; D055370:Lung Injury; D010100:Oxygen / Q000378:metabolism; D011659:Pulmonary Gas Exchange; D011663:Pulmonary Surfactants; D011817:Rabbits; D012121:Respiration, Artificial; D012140:Respiratory Tract Diseases; D013997:Time Factors
chemical_list: D011663:Pulmonary Surfactants; D010100:Oxygen