title: Oxygenation and lung morphology in a rabbit pediatric ARDS- model under high peak pressure ventilation plus nitric oxide and surfactant compared with veno-venous ECMO.
abstract: The aim of the study is to investigate which of two treatment options of saline lavage induced ARDS in rabbits is better in terms of oxygenation and prevention of barotrauma: combined high peak pressure ventilation with surfactant administration and inhaled nitric oxide or veno-venous ECMO combined with low peak inspiratory pressure ventilation.
  
  
  METHODS
  After saline lavage (10 cc/kg repeated as long as foamy retrieval was observed) two combined therapeutic strategies were examined: ventilation with high inspiratory pressures (35 cm H2O) with additional exogenous surfactant administration (100 mg/kg) and inhaled nitric oxide (10 PPM) (n=5, group 1) and low inspiratory pressure (20 cm H2O) ventilation under veno-venous ECMO support (n=5, group 2). The FiO2 was maintained at 1.0 in both groups. The paO2/FiO2 ratio was calculated in 30 minute intervals for 4 hours. After that the animals were sacrificed and the lungs examined macro- and microscopically. Aeration was described in a semiquantitative method using the alveolar expansion index. Oxygenation in group 1 was significantly better than in group 2, it increased significantly after surfactant but not after additional nitric oxide administration. However, the lungs in group 1 showed severe signs of baro/ergotrauma (Hyaline membranes, air leaks, infiltration of polymorphonuclear (PMN) granulocytes and macrophages, break down of alveolar capillary membranes) after 4 hrs of combined therapy, whereas the lungs in group 2 appeared normal. Adding surfactant and NO to a high tidal volume ventilation improved oxygenation, but did not prevent baro/ergotrauma. Ventilation with low inspiratory pressures combined with ECMO caused little baro/ergotrauma but adequate oxygenation could not be achieved, probably due to anatomical features of the rabbit which do not allow appropriate blood flow within the ECMO-circuit.
authors.affiliation: Department of Pediatrics, Medical University of Lübeck, Germany. Dmoeller@t-online.de
authors.forename: J C
authors.initials: JC
authors.lastname: Möller
authors.forename: I
authors.initials: I
authors.lastname: Reiss
authors.forename: T F
authors.initials: TF
authors.lastname: Schaible
authors.forename: M
authors.initials: M
authors.lastname: Kohl
authors.forename: W
authors.initials: W
authors.lastname: Göpel
authors.forename: T
authors.initials: T
authors.lastname: Fischer
authors.forename: E M
authors.initials: EM
authors.lastname: Nitsche
authors.forename: S
authors.initials: S
authors.lastname: Krüger
mesh_terms: D000818:Animals; D001469:Barotrauma / Q000517:prevention & control; D004195:Disease Models, Animal; D015199:Extracorporeal Membrane Oxygenation / Q000379:methods*; D006801:Humans; D007231:Infant, Newborn; D008168:Lung / Q000473:pathology*; D009569:Nitric Oxide / Q000008:administration & dosage*; D010100:Oxygen / Q000378:metabolism*; D011663:Pulmonary Surfactants / Q000008:administration & dosage*; D011817:Rabbits; D012121:Respiration, Artificial / Q000379:methods*; D012127:Respiratory Distress Syndrome, Newborn / Q000473:pathology / Q000503:physiopathology / Q000628:therapy*
chemical_list: D011663:Pulmonary Surfactants; D009569:Nitric Oxide; D010100:Oxygen