Experimental Study Of Sepsis On Blood Vessel Endothelium Injury And Clinical Research Of Central Venous Catheter-related Bloodstream Infection

Sepsis is the systemic inflammatory response to infection and premonition of multiple organ dysfunction syndrome. Nowadays, sepsis and septic shock are still the puzzle of critical care medicine in the world. Among about 750,000 patients with septic shock every year in the United States, the case fatality exceeds for 50 percent. To explore pathologic mechanism of sepsis and seek for approach to treating sepsis will have important value to instruct sepsis treating and decrease the mortality of septic shock. After blood vessel endothelium is injured by lipopolysaccharide(LPS) in sepsis, a great quantity cytokine released from endothelial cell causes the unbalance of inflammatory and anti-inflammatory system and coagulation functional disorder. In the study, sepsis model was established, and the change of blood plasma von Wilebrand factor(vWF) and endothelin(ET) were determined, and expression of vWF on lung was observed. Blood vessel endothelium injury was studied for investigating the mechanism of sepsis and seeking new approach of therapy.Objective To explore blood vessel endothelium injury in sepsis by determining the change of plasma vWF and ET, and investigate pneumonic blood vessel endothelium injury in sepsis by observing expression of vWF on lung tissue.Methods 36 New Zealand white rabbit were randomly divided into three groups(control group, sepsis group and septic shock group). 0.9% sodium chloride, LPS(1mg/kg) and LPS (2mg/kg) were injected into three groups through ear fringe vein respectively. After pressure transducer was connected with common carotid artery cannula,mean arterial pressure(MAP),heart rate(HR) and breathing frequency were monitored. In the time of 15 minutes, 30 minutes, 45 minutes, 60 minutes, 90 minutes and 120 minutes after injecting LPS, plasma vWF and ET were respectively determined by enzyme-linked immunosorbent assay and radio immunoassay. After the rabbit in the septic shock group died, lung preparation were taken and expressions of vWF on lung tissue were detected by immunohistochemical method.Results1 Sepsis and septic shock model were established.After LPS(1mg/kg) was injected into experimental animal through ear fringe vein, MAP had no obvious change, HR and breathing frequency guadually increased over 20 pencent, sepsis model was established. After LPS(2mg/kg) was injected into experimental animal, HR and breathing frequency guadually increased over 20 pencent, and MAP decreased over 20 pencent, septic shock model was established.2 Blood plasma vWF and ET increased in sepsis group and higher in septic shock groupBlood plasma vWF and ET increased remarkably after LPS was injected. Compared with control group, the extent of increasing was not clearly in the early time after injecting LPS. But when experimental animal developed septic shock, Blood plasma vWF and ET increased obviously(P<0.05).3 Expressions of vWF on lung tissue increased in sepsis and more obviously in septic shockImmunohistochemistry result displayed that positive staining of vWF was 18.86±5.32% in sepsis group and 35.58±5.45%in septic shock group, which increased obviously compared with 8.26±2.19% in control group. Conclusions1 Blood vessel endothelium injury happens in the early time of sepsis, and degree of injury aggravated along with the development of sepsis.2 Pneumonic blood vessel endothelium injury is not only the pneumonic manifestation of systemic blood vessel endothelium injury but also aggravates along with the development of sepsis.3 Blood vessel endothelium injury and dysfunction of microcirculation may play an important role in sepsis and multiorgan dysfunction syndrome(MODS).All above mentioned research results may provide the experimental basis for exploring the pathophysiology of sepsis and finding the new methods about treating sepsis and MODS. Central venous catheter is used in hemodynamic monitoring, administering fluid infusion, parenteral nutrition and blood purification. In spite of the improvement of puncturation and catheter materials, central venous catheter-related bloodstream infection(CVC-RBI) is still the severe formidable complication. In the United States of America, the number of nosocomial infection exceeds for 200,000 every year, 90 percent of which is related to central venous catheter. Catheter-related bloodstream infection, whose case fatality reaches up to 25 percent in ICU, ranks the third of nosocomial infection in ICU. CVC-RBI not only raises medical expenses, lengthens the time of hospitalization, but also is harmful to patient's state and quality of life. In the present study, the cases of CVC-RBI in ICU are investigated. Etiology and predisposing factor of CVC-RBI are explored so as to prevent and handle CVC-RBI.Objective To discuss the etiology, predisposing factor and clinic characteristic of CVC-RBI in ICU, for preventing infection and decreasing CVC-RBI, handle CVC-RBI, using CVC better in clinical work exactly.Methods The common pathogens and the risk factors of CVC-RBI were analyzed in 32 cases of CVC-RBI chosen from ICU, which was compared with the control group on patient's age, the time of hospitalization, serum albumin, Glasgow coma scales, APACHEⅡscore, enteral nutrition and incision of trachea.Results Among 32 cases with CVC-RBI, 35 pathogens were isolated,including 14 gram-positive bacterium, 10 gram-negative bacterium and 11 fungi. The incidence of CVC-RBI increased gradually after the seventh day of the insertion of catheter(90.63%). Compared with the control, 32 cases with CVC-RBI were older(P<0.05), had more length of stay in hospital and insertion time of catheter(P<0.05), higher APACHEⅡscore(P<0.001), lower serum albumin level(P<0.05) and Glasgow coma scales (P<0.001), less enteral nutrition(P<0.05) and more incision of trachea(P<0.05).Conclusions CVC-RBI should be paid attention to in older critical patients with hypoalbuminemia, incision of trachea or parenteral nutrition. Antibiotic should be used reasonably and adopt a corresponding measure according to risk factors.All above-mentioned research results may provide the important basis for using CVC in clinic work and finding the new methods about preventing and treating CVC-RBI.