Objective: To establish the trends and prognostic value of plasma levels of the free apoptotic (aDNA) and geno- mic DNA (gDNA) in patients with failure of vital functions. Type of study: Prospective observational study. Setting: University Dept. of Anaesthesiology/CCM and Dept. of Surgery, Charles University, 3rd School of Medici- ne, Prague. Material and Methods : 94 critically ill patientts were evaluated. The blood samples for DNA analysis were taken on the day of admission, the third and fifth day of hospital stay. The following data were collected: ICU admission diagnosis, age and gender, APACHE II, SOFA, ICU stay in days, ICU survival, CRP and WBC count. The analy- sis was done on a sequencer (ABI PRISM 377) using of the original phenol extraction method. The results were correlated to the plasma free DNA levels of 86 healthy volunteers (normal value = 100%). Results:The contribution of aDNA to the total plasma DNA in the critically ill was ~16fold greater than the contri- bution of gDNA. Apoptotic DNA levels were highest on the day of admission and declined thereafter (P < 0.001), whilst the opposite was true for gDNA (P < 0.001) The difference in trends and the aDNA and gDNA levels in cor- relation to normal levels was found statistically significant (P < 0.001). Apoptotic DNA on the day of admission sig- nificantly differs in survivors and non-survivors (P < 0.05). Conclusion:The free apoptotic DNA plasma level on admission could be a predictor of mortality in critical illness.

        Key words: plasma free DNA – apoptotic DNA – genomic DNA – critical care – predictors of mortality