The Research Of Plasma DNA Levels And Disease Severity And Prognosis In Critically Ill Patients

ObjectiveDetection the concertration of cell-free plasma DNA in Emergency Intensive Care Unit by Polymerase Chain Reaction and explore the quantitative analysis of plasma DNA concentration as a minimally invasive, rapid detection of targets, whether sensitivity and specificity to reflect the severity of disease of critically ill patients; Clarify the plasma DNA and ICU mortality aging, dose-effect relationship; Confirmed that plasma DNA helps improve the ability to predict clinical severity of the disease in critically ill patients.MethodsA prospective study from June2012to June2013period, the First Affiliated Hospital of Anhui Medical University,190cases of critically ill patients admitted to the EICU. We obtained blood samples5ml on the day after admitted into EICU immediately and24,48,72h,1w later. The concertration of cell-free plasma DNA at different time points was measured by real-time quantitative polymerase chain reaction assay for the human β-globin gene. According to the prognosis, the patients were divided into survival group (131cases) and nonsurvival group (59cases). Basic clinical data collected:sex, age, if use mechanical ventilation, if use blood purification therapy, whether primary infection, whether secondary infection, if use of vasoactive drugs at the first day of admission, EICU retention time (days) and so on. Record APACH II score after admitted into EICU24h,48h,1w later. Acquisition laboratory indicators include:peripheral, liver and kidney function, blood gas analysis, plasma lactate, procalcitonin (PCT), lactate, interleukin-6, C-reactive protein.Analysis of the correlation between laboratory parameters between the two groups, clinical outcome measures and plasma DNA concentration. The control group included30healthy adults, from the hospital medical center, age,gender matched with the study group.Results1. Compared with control group, the level of cell-free plasma DNA concentration was significantly higher in EICU patients at each time point (p<0.05).2. There was no significant difference between the survival group and the death groups for the reasons admission EICU.3. The levels of plasma DNA at the highest point when admit EICU, decreased with disease progression, with the lowest point at1week after the admission.4. Cell-free plasma DNA concentrations were significantly higher at24h and48h time points in EICU non-survivors than in survivors (p<0.05), while other basic clinical datas and aboratory indicators had no differents.5. ROC analysis showed that, cell-free plasma DNA was of more significant diagnostic value for predict the severity of illness and mortality than the lactate and APACHE II scores for critical patients, the maximum of AUC was0.847(95%CI0.648-1.000)at the point of48h after admission.Conclusion1. The concentration of cell-free plasma DNA is higher in EICU patients than control group;2. Cell-free plasma DNA concentration is independently associated with the severity of illness and hospital mortality.3. The study suggest that cell-free plasma DNA concentration is potentially useful as a prognostic marker in EICU critical patients.