| Objective:1.To establish an ALI/ARDS animal model in rats caused by severe pneumonia infected by Escherichia coli (E. coli) to mimic clinical conditions caused by G- bacilli. Morphological observation would see bilateral lungs inflammatory changes being widespread, affecting most of the parenchyma in the majority of the rats. The ALI/ARDS model criterion: PaO2/FiO2<300mmHg is considered as ALI , PaO2/FiO2<200mmHg is considered as ARDS. Observe the developments of ALI/ARDS rats from the onset of making model and show the changing tendence of blood gas in many time points in order to offer alternated material for further experiment.2. To investigate the beneficial effects of exogenous surfactant supplementation in treating the ALI/ARDS rat model.3. To investigate the beneficial effects of exogenous surfactant supplementation on the survival of ALI/ARDS model rats at the early time of ALI.Methods: The procedure was done with three steps.1. Establish an ALI/ARDS animal model: It was done by two steps. The first step was to observe the infected rats for 72 hours. The second steps was to divide the following 100 observing hours into ten time segments.1.1 Methods of infected rats: Tracheostomy was performed through cervical median incision after rats were anesthetized. They were received transtracheal application of 3ml/kg alive E. coli suspended fluid [ (4.4-5.6 ) × 109CFU/ml ] . The incision was closed after the operation. Then the rats were set free with a free drinking and eating.1.2 72 hours observation of the infected rats. 40 rats were randomly allocated to groups: Alive E. coli group (n=24), normal saline group(n=8), dead E. coli group... |
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