[Analysis of evaluation indexes for prognosis of severe burn patients with sepsis].

Objective: To compare changes in indexes and analyze their values in prognosis of severe burn patients with sepsis.
Methods: A retrospective analysis was conducted. The patients with severe burn sepsis admitted to the Third Affiliated Hospital of Soochow University from August 2014 to December 2016 were enrolled. The blood culture was positive in the clinical diagnosis of sepsis. According to the prognosis, the patients were divided into death group and survival group. Their general information, vital signs, blood routine examination, serum sodium (Na ⁺ ), serum glucose (Glu), C-reactive protein (CRP) and arterial partial pressure of carbon dioxide (PaCO ₂ ) at the time of admission and diagnosis of sepsis as well as the level of serum procalcitonin (PCT) at admission, diagnosis of sepsis and 1-8 days of post diagnosis were also compared. Receiver operating characteristic curve (ROC) was used to analyze the prognostic value of each index, and multivariate Cox regression analysis was used to analyze the influence of each index on the survival time, and the survival curve of Kaplan-Meier was analyzed for dead patients.
Results: There were 25 cases of severe burn patients with sepsis, which were admitted to hospital within 12 hours after injury; the time of diagnosis of burn sepsis was (14±6) days; 8 cases of survival; 17 cases died, the mortality rate was 68.0%, the time from diagnosis of sepsis to death was (28±14) days. The age of the death group was significantly higher than that of the survival group (years: 41±12 vs. 29±9, t = 2.598, P = 0.016), but there was no significant difference in the gender, total burn area, III degree area, and the time of diagnosis of sepsis between the two groups. The platelet count (PLT) at the diagnosis of sepsis in death group was significantly lower than that of the survival group (×10 ⁹ /L: 69±43 vs. 180±108, t = -2.773, P = 0.023), and the PCT at 1-8 days of post-diagnosis in the death group was significantly higher than that of survival group [μg/L: 4.4 (2.2, 9.0) vs. 1.6 (0.7, 2.3), Z = -2.521, P = 0.012], but there was no significant difference in body temperature, heart rate, white blood cell count (WBC), percentage of neutrophils (Neu), Na ⁺ , Glu, CRP, PCT, PaCO ₂ at the time of admission and diagnosis of sepsis and PLT at the time of admission between the two groups. ROC curve analysis showed that the area under ROC curve (AUC) of age, PLT at the time of diagnosis and PCT at 1-8 days of post-diagnosis of sepsis was 0.808, 0.779, 0.825, respectively, for predicting the prognosis of patients with severe burn sepsis (all P < 0.05). At the cut-off age of 32, the sensitivity was 73.3% and the specificity was 75.0%. As the cut-off of PLT was 138×10 ⁹ /L at the time of diagnosis, the sensitivity was 92.3% and the specificity was 75.0%. As the cut-off of PCT was 2.39 μg/L at 1-8 days of post-diagnosis of sepsis, the sensitivity was 73.3% and the specificity was 87.5%. Multivariate Cox regression analysis showed that age and PLT at the time of diagnosis were the favorable factors for the survival time of patients with severe burn sepsis (β value were -1.834, -0.029, respectively, both P < 0.05). Kaplan-Meier survival analysis for patients in the death group showed that the median survival time of patients ≥32 years old was longer than that of patients < 32 years old (days: 32 vs. 9); 18-day cumulative survival rate was significantly higher than that of patients < 32 years old [83.3% (10/12) vs. 25.0% (1/4), χ ² = 9.705, P = 0.003].
Conclusions: Age, PLT at diagnosis of sepsis and PCT at 1-8 days after diagnosis of sepsis could be used as prognostic indexes for severe burn patients with sepsis.