To evaluate the effect of extravascular lung water index (EVLWI) and procalcitonin (PCT) on the severity of burn sepsis caused by Gram-negative bacilli.

From March 2015 to March 2019, 20 patients with burn sepsis of Gram-negative bacilli (Gram-negative bacilli burn sepsis group) and 18 patients with burn sepsis of non Gram-negative bacilli (non Gram-negative bacilli burn sepsis group) who were hospitalized in the Department of Burns, Tongren Hospital of Wuhan University & Wuhan Third Hospital were selected in this study. The patients in both groups were monitored with pulse indicating continuous cardiac output (PiCCO), and the changes of values of EVLWI when diagnosed sepsis and septic shock were recorded. The values were averaged for 3 times, and the mean values were taken. When the patients were diagnosed with sepsis or septic shock, venous bloods of patients were collected immediately, 3 mL of non-anticoagulant blood was collected, and serum was retained after centrifugation and detected for PCT, and the PCT values of patients were recorded in both groups. The differences of EVLWI and PCT between the two groups were compared, and data were processed with t test, Bonferroni correction. The receiver operating characteristic (ROC) curves of EVLWI and serum PCT in predicting burn sepsis and septic shock patients with Gram-negative bacilli were drawn, and 95% confidence interval, Youden index, best critical value, sensitivity and specificity for the diagnosis of burn sepsis or septic shock patients caused by Gram-negative bacilli were calculated.

When the patients were diagnosed for sepsis, the values of EVLWI and PCT of patients in Gram-negative bacilli burn sepsis group were (10.6 ± 1.6) mL/kg and (6.64 ± 1.63) ng/mL respectively, which were higher than those in non Gram-negative bacilli burn sepsis group [(7.9±1.7) mL/kg and (4.60±1.31) ng/mL respectively], and the differences between the two groups were statistically significant (t=5.043, 4.206; with P values below 0.05). When the patients were diagnosed for sepsis shock, the values of EVLWI and PCT of patients in Gram-negative bacilli burn sepsis group were (15.0±1.3) mL/kg and (12.87±2.65) ng/mL respectively, which were higher than those in non Gram-negative bacilli burn sepsis group [(10.7±1.5) mL/kg and (6.29±1.79) ng/mL], and the differences between the two groups were statistically significant (t=9.608, 8.867; with P values below 0.05). By drawing ROC curve, the values of EVLWI and PCT which were used to determine the best critical values of burn sepsis patients caused by Gram-negative bacilli and burn sepsis patients caused by non Gram-negative bacilli were 10.5 mL/kg and 5.9 ng/mL respectively, with Youden index of 50% and 59%, sensitivity of 50% and 70%, and specificity of 100% and 89% respectively. The best critical values of EVLWI and PCT in the diagnosis of burn septic shock of gram negative bacilli and burn septic shock of non gram negative bacilli were 13.5 mL/kg and 9.2 ng/mL respectively, with Youden index of 90% and 95%, sensitivity of 90% and 95%, and specificity of 100% and 100% respectively.

EVLWI and PCT can be used as effective indexes to evaluate the severity of burn sepsis caused by Gram-negative bacilli, and can further improve the accuracy of risk prediction of burn sepsis caused by Gram-negative bacilli.