The value of sepsis biomarkers and their kinetics in the prognosis of septic shock due to bacterial infection

Background: In this study, we aim to explore the value of procalcitonin (PCT), C-reactive protein (CRP), and serum cholinesterase (SChE) activity kinetics as useful predictors of mortality in patients with septic shock admitted to the intensive care unit (ICU). Methods: We conducted a prospective single-blinded study in the ICU of a university hospital during a period of 1 year. Were included all patients 18 years of age or older, with confirmed septic shock. For all included patients, blood samples of septic biomarkers (PCT, SChE activity, and CRP) were obtained. Serum was collected at the day of ICU admission (day 0), the day of septic shock (day 1), then 3 and 5 days after the septic shock development. Results: During the study period, 60 patients were included. The mean age (+/- SD) was 47.7 +/- 19 years. There were 46 male (74%) and 14 female (26%) patients. Mean SAPSII on ICU admission was 40.7 +/- 16 (median: 37), and mean SOFA score on ICU admission was 16 +/- 4 (median: 7). During their ICU stay, out of the 60 included patients, 37 patients died (61%). The comparison between the 2 groups (deaths and survivors) showed that the factors associated with poor outcome were age, SOFA score on ICU admission, and the need for invasive mechanical ventilation. The day of septic shock, there was no difference in the mean concentrations in those of plasma SChE activity or in the PCT and CRP plasma between survivors and non-survivors. However, the comparison of mean plasma SChE activity, and PCT and CRP plasma concentrations (on day 3 and day 5) between survivors and non-survivors, showed a significant difference between the 2 groups. Conclusions: Our study suggests that, in a group of critically ill patients with severe septic shock, a rise or no change in procalcitonin and/or CRP level, and/or a decrease or no change in SChE activity should warn the clinician about the insufficiency and/or inadequacy of the therapy. However, a fall in procalcitonin and/or CRP levels, and/or a rise in SChE activity were associated with a favourable prognosis. Based on our study and some other data detailed above, we recommend that an estimation of SChE activity, procalcitonin, and CRP on the day of septic shock, followed by estimation within the next 72-120 h, could help the prognostic assessment of critically ill patients with septic shock. Further studies are needed to define the critical values related to mortality.