Background: To explore the value of dynamic monitoring of procalcitonin (PCT) for early identification of pathogens and prognosis of bloodstream infections (BSI) in the intensive care unit (ICU).
Methods: A retrospective analysis was performed on 84 patients with positive blood cultures. Patients were divided into the survival group and death group according to prognosis. Dynamic changes of PCT before and after treatment in the two groups were compared, as well as the relationship between such changes and prognosis.
Results: Among the 84 patients with bloodstream infections, 41 cases of Gram-negative (G-) bacteria, 40 cases of Gram-positive (G+) bacteria, and 3 cases of fungi were detected. PCT value in the G- bacteria group was significantly higher than that in the G+ bacteria group and fungus group, and the difference was statistically significant (P<0.05). PCT values on the first day of the G- bacteria group and the non-G- bacteria group were analyzed by a receiver operating characteristic (ROC) curve. When the threshold value was 3.84 ng/mL, the sensitivity, specificity, and area under the ROC curve for predicting G- bacteria bloodstream infection were 61%, 92.5%, and 0.841, respectively. The Kruskal-Wallis test (K-W test) was performed on PCT levels of each G- bacteria on the first day of bloodstream infection, and the difference was not statistically significant (P>0.05). Logistic binary regression analysis showed that the reduction rate of PCT after 5 days of treatment was an independent protective factor for patient survival. ROC curves showed that the sensitivity and specificity for predicting patient survival were 88% and 68.7%, respectively, when the PCT reduction rate (PCT(D1-D5)/D1) reached 36.02% or more.
Conclusions: PCT can be used as an adjunctive method to quickly diagnose pathogenic microorganisms of bloodstream infections, and the anti-infection treatment scheme has certain guiding value. The dynamic changes in PCT have a certain role in predicting the therapeutic effect and prognosis of anti-infection treatment.
Keywords: Bloodstream infection; blood culture; pathogenic microorganism; procalcitonin (PCT); prognosis.