| Objective:To explore a new treatment method of moderate and severe acute respiratory distress syndrome(ARDS),the most suitable dose of oleic acid (OA) for the model was firstly ascertained in according to the appearance time of typical symptom and the changes of pathological characteristics, x-ray of chest and cytokine level in plasma, then the model with ARDS induced by oleic acid in beagle dogs was successfully established. Methods:29 beagle dogs(16 male,13 female)with 9-14kg,mean(11.4±3)kg,were given an intubatton after anesthetized with 0.3ml/kg sumingxi via muscle injection. The arterial blood gas, acid-base status,electrolytes, concentration of TNF-α,IL-8,IL-10 in plasma, and renal functions were respectively determined before OA injection. It was injected with 0.10mg/kg oleic acid via vena cervicis, The arterial blood gas was detected every one hour till the value of PaO2/FiO2 was smaller than 200mmHg.the dosage were mechanically ventilated with CMV mode with a tide air volume of 6-8ml/kg,a positive expiratory end-pressure(PEEP)of 5cmH2O,a fractional oxygen concentration of 0.4.respiratory rates of between 18-20breaths/min.after mechanical ventilation one hour ,if value of PaO2 /FiO2 was larger than 200mmHg, it was injected with 0.025mg/kg oleic acid again until value of PaO2 /F iO2 was smaller than 150mmHg.X-ray of chest,electrolytes(K+,Na+2,Cl-)in serum,and levels of TNF-α,IL-8,IL-10 in plasma were measured again.At the end of experiment, experimental dogs were sacrificed with an overdose diazepam ,the lung were excised,weighed,explored features of pathology,aid-dried after which they were weighed again to determine the wet-to-dry ratio. Results:1.ARDS beagle dogs produced in 4 to 8 hour period after OA administration;Dosage of OA was mean 0.175±0.015 ml/kg.2.Respiratory rate of ARDS beagle dogs was mean 64.1±21.1 breaths/min.The lung compliance was decreased(P<0.05)3.Pathology of moderate and severe ARDS in our experiment was characterized by heave lung edema included large serum protein,it showed marked alveolar epithelial cells swelling and inflammation cells,marked venous thrombosis,and hyaline membranes 4.Wet -to-dry lung tissue ratio was 8.5±0.6.5.The chest radiograph revealed diffuse bilateral infiltrates consistent with pulmonary edema in middle and low lung lobes.6.PaO2 /F iO2 was smaller than 150mmHg;Metabolicacidosis occurred in some dogs.7.The concentrations of TNF-α,IL-8,IL-10 in plasma were higher than that before OA injection (P<0.05). Conclusions:To establish successfully moderate and severe acute ARDS beagle dog model by OA.the dosage of OA was mean 0.175±0.015 ml/kg;wet -to-dry lung tissue ratio was 8.5±0.6;The characteristics of pathology showed heave lung edema included large serum protein and marked venous thrombosis,there were hyaline membranes.The concentrations of TNF-α,IL-8,IL-10 in plasma were higher than the baseline.The lung compliance was decreased.Objective:To study the effects of compressing lung drain fluid(CLDF)technique and sustained inflation(SI)technique on oxygenation,lung mechanics,plasma cytokines,X-ray of chest and survival time in beagle dogs with moderate and severe acute respiratory distress syndrome. Methods:1.To establish the model beagle dogs induced by oleic acid with moderate and severe ARDS .Twenty nine beagle dogs were divided into three groups,15 dogs in A group,6 dogs in B group,and 8 dogs in C group.2.Compressing lung drain fluid(CLDF)was performed on A group at pressure of 15cmH2O～20 cmH2O for 15 s,and lung fluid was absorbed immediately,then mechnical ventilation followed;sustained inflation was performed on B group at 35cmH2O～40 cmH2O airway pressure for 20s, then mechnical ventilation followed;TMV on C group with CMV or BIPAP mode(Drager or Taema HARUS),with a tide air volume of 6～8ml/kg,a positive expiratory ene-pressure of 5 cmH2O,a fractional oxygen concentration of 0.35 ～ 0.50.respiratory rates of between 18 ～ 20breaths/min.3.Blood gas,lung mechanics,CVP,electrolytes were investigated.Levels of plasma TNF- α...
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