Application Of Continuous Renal Replacement Therapy In Patients With Acute Respiratory Distress Syndrome

Objective:Acute respiratory distress syndrome(ARDS),mostly triggered by underlying multi-causes such as sepsis,severe trauma,shock and others,is the manifestations of systemic inflammatory response syndrome(SIRS)in the lungs,and the terminal phase of serious acute lung injure(ALl).Despite ongoing and intensive scientific research in this area,especially the application of the lung-protective ventilation with small tidal volumes,and until recently,the mortality from acute lung injury(ALl)and ARDS(ALI/ARDS)has decreased as laboratory and clinical studies have provided new evidence to improve therapeutic strategies,but still stayed at a high level,most reported mortality rates were about 50%,and even exceeded 90%when followed by multiple organ dysfunction syndrome(MODS);However,the underlying mechanisms of ALI/ARDS are still not completely understood,and up to now there are not specific therapies for ALI/ARDS.Therefor,to study the pathogenesis mechanism of ALI/ARDS and its specific therapies are one of the most chanllenging entity we are facing now.In our research,we investigate the changes of IL-6 serum level in patients with acute respiratory distress syndrome,and the effects of continuous renal replacement therapy(CRRT)on serum IL-6 and its clinical significance, then in order to do something for the further resesrch.Methods:40 ARDS patients were randomly divided into two growps:20 patients treated conventionally(group A)and 20 patients who received conventional treatment plus CRRT(group B)at onset of ARDS. Serum IL-6 level in patients with ARDS was measured by enzyme linked immunosorbent assay(ELISA)at onset(0h)and during the progression of ARDS(12h,24h,48h,72h).Dynamic APACHEⅡscore was also evaluated(0h,24h,48h,72h).The incidence of ventilator-associated pneumonia(VAP),the intensive care unit(ICU)mortality rate,duration of total mechanical ventilation and ICU stay were assessed.Results:In comparison with normal control group,the serum level of IL-6 in patients with ARDS was all over-high(P＜0.01),which also differed significantly between the survival group and nonsurvival group(P＜0.01).IL-6 serum level correlated well with APACHEⅡscore either in survival group or in nonsurvival group(the former r=0.560 P=0.008,the latter r=0.518 P=0.023).The group B,contrary to group A, had persistently decreased serum IL-6 level and APACHEⅡscore at onset and during the progression of ARDS(all P＜0.05).The incidence of VAP(45%)in group B patients was significantly lower than that(80%) in group A patients(P=0.022)while the ICU mortality rate didn't differ between the two groups(40%Vs 55%,P=0.342).In group B patients, those with early CRRT had the duration of total mechanical ventilation of 12.15±4.79 days and ICU stay of 15.50±5.17 days which were shorter than those of group A patients(15.65±4.82 days,P=0.027 and 19.05±4.77 days,P=0.03).Conclusion:The elevated serum IL-6 level in patients with ARDS seems to be correlated well with the severity of lung injury,and appears to be a good marker to judge the prognosis of the disease combined with APACHEⅡscore.In the early phase of ARDS,CRRT can decrease the high serum level of IL-6,shorten duration of total mechanical ventilation and ICU stay,decrease the incidence of VAP,improve prognosis in patients with ARDS,so removal of the circulating proinflammatory cytokines by CRRT may be one of the most vital mechanisms to treat ARDS patients.