The Comparison Of Sevoflurane Preconditioning And Postconditioning To Infrarenal Aorta Ischemia-reperfusion Induced Lung Injury

Objective:The purpose of our experiment is to compare the protective effect of sevoflurane preconditioning and postconditioning in infrarenal aorto ischemia-reperfusion induced lung injury.Method:Heathy SD rats grouped in 4 group randomly,each of the group have 10 rats.Groupâ… Sham.Groupâ…¡ischemia-reperfusion; ischemia by clamping of the infrarenal aorta for 2h followed by 3h of reperfusion.Groupâ…¢sevoflurane preconditioning;2.0%sevoflurane administered over 30 min prior to ischemia.Groupâ…£sevoflurane postconditioning;2.0%sevoflurane during reperfusion.The right carotid artery was cannulated to measure blood pressure(BP),to sample arterial blood and to substitute saline(NaCl 0.9%;Braun) to compensate for fluid losses due to instrumentation and evaporation.Arterial blood samples were drawn before ischemia,at the end of ischemia and in hourly intervals during the reperfusion period.At the end of the experiment,the left lung was used to determined the W/D ratio,the right lung was used to observe lung tissue and inferior-cell structure change under the light microscope and electron microscope.Result:1 Baseline values derived from arterial blood sample determinations(PaO₂,PaCO₂)did not differ significantly between the groups.Blood sample values did not differ significantly in the group in different times.2:Compared with I/R and I/R+Post white blood cells were reduced significantly in group I/R+Pre.3:The W/D ratio of lung was significantly higher in group I/R and I/R+Post than in group Sham and I/R+Pre.There was not significantly differences between group I/R and I/R+Post.4:Histological examination showed intralveolar edema and hemorrhage,abundant leukocytes accumulation,capillary hyperemia in group I/R.That showed moderate injury in group I/R+Pre and the histological change in group I/R+Pre was less significantly than those in the group I/R and I/R+Post and lung tissue had normal pulmonary parenchyma in group Sham.5:Electron microscope demonstrated mitochondria of alveolar typeâ…¡cells swelled and their crista disappeared or shorten;mitochondria swelling also was showed in group I/R+Post,but it was less than that in group I/R.Mitochondria only mildly swelled in group I/R+Pre,integrity of the endothelial ceils,mitochondria and the integrity of the contents of the cytoplasm,normal blood barrier(no interstitial edema,vascular endothelial normal)。There isn't significantly difference between I/R and I/R+Post.Conclusion:Sevoflurane preconditioning not postconditioning has the effect of lung protection by reducing white blood cells accumulation and reducing lung injury.