| ObjectiveTo study the therapeutic effects of vaporized perfluorocarbon(PFC)and exogenous surfactant on saline lavage-induced acute respiratory distressed syndrome(ARDS).MethodsThirty-two New Zealand rabbits,weighing 2.0 to 2.5 kg,were anesthetized and restrained in the supine position.An endotracheal tube was inserted into the trachea and two catheter were inserted into the right carotid artery and vein to sample blood.The experimental animals were randomly assigned into four groups,sham group(n=8),oxygen treatment group(n=8),model group group(n=8),and non oxygen treatment group(n= 8).After 30 min of stabilization of the above experimental condition,Respiratory rate(RR),dynamic compliance(Cdyn)were recorded and arterial blood gases were analyzed as baseline data.In the model group and two treatment groups,ARDS was induced by a saline lavage protocol,with minor modification of the technique described previously by Lachmann et al.The warmed sterile saline(10ml/kg at 37?)was instilled via the endotracheal tube,the rabbits were gently rocked from side to side in order to distribute saline uniformly and fluids were removed after 20 s.The lavage process was repeated three times and each lavage was performed at 5 minute interval.After 30 minutes,blood gas sampling was done.When oxygenation index(OI)was maintained below 300 mm Hg for 30 min,we assumed that a surfactant-depleted ARDS model was completed.The rabbits in sham group underwent tracheotomy and catheterization in the right femoral artery and vein without lavage.After induction of ARDS,oxygen treatment group was treated with preoxygenated PFC and surfactant at the dose of 3 ml/kg,non oxygen treatment group was treated with PFC and surfactant without preoxygenation at the same dose.Respiratory rate,oxygenation index,dynamic compliance were observed at 30 min after induction of ARDS(baseline),the time before treatment and 0 min,30 min,2h,4h after treatment.Lung index(LI),lung permeability index(LPI)were calculated,the concentrations of tumor necrosis factor-alpha(TNF-?)and interleukin-1 beta(IL-1?)were measured in the plasma and lung tissue,the concentration of intercellular adhesion molecule-1(ICAM-1)in lung tissue was determined and the lung pathological changes were observed under macroscopic and light microscope.ResultsCompared to sham group,we observed significantly decreased oxygenation index and dynamic compliance,an increased rate of breathing and lung damage in model group,oxygen treatment group and non oxygen treatment group after the induction of ARDS.Significantly higher OI developed in oxygen treatment group than in model group at 0min,2h and 4h(0min:231.0±16.7 vs 189.5±21.0;2h: 282.4±15.7 vs 244.8±32.4;4h: 347.1±27.1 vs 243.3±36.7,P<0.05),OI was increased in non oxygen treatment group at 2h and 4h(P<0.05).However,OI in the oxygen treatment group was significantly higher than that in the non oxygen treatment group at 0min and 4h(0min 231.0±16.7 vs 190.5±13.3;4h 347.1±27.1 vs 313.3±21.0,P<0.05),proving that both of the treated groups had a significant improvement on the oxygenation index in the ARDS model,but the effect of the oxygen treatment group was better than that of the non oxygen treatment group;Respiratory rate in these two treated groups was increased significantly at 30 min and 2h,compared to model group(P<0.05).Aerosol treatment resulted in statistically significant changes in dynamic compliance,lung index,lung permeability index,the concentrations of TNF-?,IL-1?,ICAM-1 in the plasma and lung tissue and pathologic analysis scores(P<0.05),there was no significant difference between the two treated groups(P>0.05).ConclusionVaporized perfluorocarbon and exogenous surfactant(PFOB/DPPC emulsion)can provide greater oxygen delivery,reduce the pro-inflammatory cytokines,contribute to pulmonary surfactant supplement and influence its distribution on the surface of lung,which might lead to a marked and sustained improvement in oxygenation,pulmonary function and lung pathology in saline lavage-induced ARDS model. |
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