[Epidemiological characteristics and risk factors of sepsis development and death in patients with extremely severe...

Objective: To explore the epidemiological characteristics and risk factors of sepsis development and death in patients with extremely severe burns. Methods: A retrospective case series study was conducted. From January 2017 to December 2021, 135 patients with extremely severe burns who met the inclusion criteria were admitted to the Department of Burn and Wound Repair of the Second Affiliated Hospital of Zhejiang University School of Medicine, including 100 males and 35 females, aged 18-84 years. The incidence and diagnosis time of sepsis, the rate of positive microbial culture of blood samples (hereinafter referred to as positive blood culture), and the mortality rate of all patients, as well as the incidence of sepsis and the pathogen of infection in patients with positive blood culture were recorded (statistically analyzed with chi-square test or Fisher's exact probability test). According to the occurrence of sepsis, all patients were divided into sepsis group (58 cases) and non-sepsis group (77 cases), and the gender, age, body mass index, history of hypertension, history of diabetes, combination of inhalation injury, burn site, burn type, total burn area, and combined injury of patients were compared between the two groups. According to the outcome, all patients were divided into death group (37 cases) and survival group (98 cases), and the aforementioned data grouped according to sepsis as well as the stability of shock period and the combination of sepsis of patients were compared between the two groups. The aforementioned data between two groups were statistically analyzed with univariate analysis of independent sample t test, Wilcoxon rank-sum test, Mann-Whitney U test, chi-square test, or Fisher's exact probability test. Factors with P<0.1 were selected for multivariate logistic regression analysis to screen independent risk factors of sepsis and death in patients with extremely severe burns. Results: Among all patients, the incidence of sepsis was 42.96% (58/135), the diagnosis time of sepsis was 14 (7, 24) d after injury, the positive blood culture rate was 62.22% (84/135), and the mortality rate was 27.41% (37/135). The incidence of sepsis of patients with positive blood culture was 69.05% (58/84). The top 5 pathogenic bacteria in the detection rate of septic patients with positive blood culture were Acinetobacter baumannii, Klebsiella pneumoniae, Pseudomonas aeruginosa, Staphylococcus aureus, and Enterobacter cloacae, ranking from high to low, and the proportion of Acinetobacter baumannii infected was significantly higher than that of non-septic patients with positive blood culture (χ²=7.49, P<0.05). Compared with those in non-sepsis group, the proportion of combination of inhalation injury, the proportion of perineal burns, and the total burn area of patients in sepsis group increased significantly (with χ² values of 11.08 and 17.47, respectively, Z=5.68, P<0.05), while the other indicators did not change significantly (P>0.05). Multivariate logistic regression analysis showed that combination of inhalation injury, total burn area ≥80% total body surface area (TBSA), and perineal burns were independent risk factors for patients with extremely severe burns developing sepsis (with odds ratios of 3.15, 7.24, and 3.24, respectively, with 95% confidence intervals of 1.07 to 9.29, 1.79 to 29.34, and 1.21 to 8.68, respectively, P<0.05). Compared with those in survival group, the proportion of combination of inhalation injury, the proportion of perineal burns, and the proportion of combination of sepsis (with χ² values of 6.55, 11.64, and 22.26, respectively, P values all <0.05), total burn area (Z=4.25, P<0.05), and proportion of instability of shock period (P<0.05) of patients in death group all increased significantly, while the other indicators did not change significantly (P>0.05). Multivariate logistic regression analysis showed that the instability of shock period and combination of sepsis were independent risk factors for death of patients with extremely severe burns (with odds ratios of 4.87 and 3.45, respectively, with 95% confidence intervals of 1.21 to 19.57 and 1.28 to 9.33, respectively, P<0.05). Conclusions: Patients with extremely severe burns have a high incidence of sepsis and a high mortality rate. The peak period of sepsis onset is 2 weeks after injury, with Acinetobacter baumannii as the most prominent infectious pathogen. Combination of inhalation injury, total burn area ≥80% TBSA, and perineal burns are independent risk factors for extremely severe burn patients complicated with sepsis, and combination of sepsis and instability of shock period are independent risk factors for death of patients with extremely severe burns.