Analysis of prognostic risk factors of bloodstream infection in intensive care unit patients

Abstract

To explore the prognostic risk factors of bloodstream infection (BSI) in intensive care unit (ICU) patients, furthermore, to provide a reliable evidence for early warning and treatment for the critical patients with BSI. A retrospective study was performed. The clinical data of patients with blood culture-positive admitted to ICU of the Affiliated Hospital of Guizhou Medical University from January 1 to September 30, 2019 were analyzed. The data including gender, age, proportion of basic diseases, acute physiology and chronic health evaluation II (APACHE II), the duration of mechanical ventilation after being diagnosed with BSI, length of stay in ICU, aggressive operation and blood product infusion after BSI, proportion of using continuous renal replacement therapy (CRRT) and continuous vasoactive agents for more than 72 hours after being diagnosed with BSI, and site of central venous catheterization were recorded. Meantime, the worst laboratory values within 72 hours after being diagnosed with BSI, information about pathogenic microorganism categories and distributions were collected and analyzed. The patients were divided into survival and death groups based on the the 28-day prognosis, and the differences of clinical data between the two groups were compared. Logistic regression analysis was used to select the independent prognostic risk factors of BSI. One hundred and fifty-four patients with positive results of BSI were enrolled, and the 156 strains of bacteria were detected, including 75 Gram positive (G+) bacteria strains, 70 Gram negative (G-) bacteria strains and 11 fungi strains among those BSI patients. The top five pathogenic microorganisms were Coagulase negative staphylococcus (35.9%), Klebsiella pneumonia (12.8%), Acinetobacter baumannii (9.0%), Enterococci (9.0%), and Escherichia coli (8.3%). There were 45 strains (60.0%) of multidrug-resistant strains in G+ bacteria and 40 strains of multidrug-resistant strains (57.1%) in G- bacterial strains, but in fungi there was only 1 strain (9.1%). There were 81 cases in survival group and 73 cases in death group according to 28-day prognosis. We found that there were no significant differences between the comparators in age, lenth of stay in ICU, duration for mechanical ventilation after being diagnosed with BSI, percentage of BSI with chronic obstructive pulmonary disease (COPD), hypertension, cardiovascular disease or chronic kidney dysfunction (all P > 0.05). In death group, the proportion of male was obviously lower than that of survival group [58.9% (43/73) vs. 75.3% (61/81), P < 0.05] and APACHE II score was significantly higher than that in survival group (27.1±7.0 vs. 19.5±6.7, P < 0.05). The mean arterial pressure (MAP) of death group on first 3 days of BSI was significantly lower than that of survival group [mmHg (1 mmHg = 0.133 kPa): 72.8±13.6 vs. 79.7±12.9, P < 0.05), in the death group, the proportion of patients complicated with diabetes, cancer [28.8% (29/73) vs. 12.3% (10/81), 19.2% (14/73) vs. 7.4% (6/81)], post-BSI CRRT and blood transfusion [39.7% (29/73) vs. 16.0% (13/81), 64.4% (47/73) vs. 46.9% (38/81)], and continuous use of asoactie drugs for ≥ 72 hours [37.0% (27/73) vs. 12.3% (10/81)] were significantly higher than those in the survival group (all P < 0.05). In death group, platelet count (PLT) was significantly decreased than that of survival group [×109/L: 124.93±98.21 vs. 181.15±116.39,P < 0.05], aspartate aminotransferase (AST) level was significantly higher than that of survival group [U/L: 75.40 (38.50, 140.95) vs. 56.20 (29.20, 85.70), P < 0.05], the rest of the laboratory indexes had no statistically significant differences between the two groups (all P > 0.05). The results of Logistic regression analysis showed that the APACHE II score [odds ratio (OR) = 1.279, 95% confidence interval (95%CI) was 1.158 to 1.412, P < 0.001], CRRT after BSI (OR = 3.522, 95%CI was 1.013 to 12.245, P = 0.048) were independent risk factors affecting the prognosis of patients with BSI, and MAP is a protective factor for prognosis (OR = 0.961, 95%CI was 0.927 to 0.996, P = 0.031). In our ICU, G+ bacteria are still dominant in bloodstream infection, G- bacteria take the second place. Besides, APACHE II score and CRRT after being diagnosed with BSI are the independent prognostic risk factors.