To investigate the correlation between human high mobility group protein B1 (HMGB-1), receptor of advanced glycation endproducts (RAGE), C-reactive protein (CRP) and the severity of pulmonary infection after brain trauma surgery and to evaluate the prognosis of the disease.

Total of 182 patients with pulmonary infection after operation of brain trauma who were treated in Affiliated Peace Hospital, Changzhi Medical College from May 2016 to May 2018, prospectively. According to the CURB-65 scoring system for lung infection (CURB-65), patients were divided into mild group (74 cases), moderate group (60 cases) and severe group (48 cases). According to the clinical outcome of 30 days after operation, the patients were divided into survival group (151 cases) and death group (31 cases). The serum levels of HMGB-1, RAGE and CRP in patients with different infection degrees were compared and their correlation between the severity of pulmonary infection were analyzed, respectively. The risk factors of death were determined by Logistic regression analysis and the predictive value of HMGB-1, RAGE and CRP to the death of patients with pulmonary infection after traumatic brain injury were evaluated by receiver operating characteristic curve (ROC).

The level of HMGB-1 of patients in severe group was (10.22 ± 2.35) μg/L, significantly higher than those of moderate group [(3.89 ± 1.01) μg/L] and mild group [(2.00 ± 0.40) μg/L], with significant differences (t = 18.821, 29.502; both P < 0.001). The level of RAGE of patients in severe group was (9.01 ± 2.05) ng/L, significantly higher than those of in moderate group [(5.89 ± 1.20) ng/L] and mild group [(2.12 ± 0.22) ng/L], with significant differences (t = 9.870, 28.722; both P < 0.001). The level of CRP of patients in severe group was (50.33 ± 10.32) mg/L, significantly higher than those of the moderate group [(32.33 ± 8.52) mg/L] and mild group [(15.20 ± 3.52) mg/L], with significant differences (t = 9.930, 27.010; both P < 0.001). The serum levels of HMGB-1, RAGE and CRP of patients in moderate group were all higher than those of mild group, with significant differences (t = 14.744, 26.504, 15.729; all P < 0.001). The serum levels of HMGB-1, RAGE and CRP were positively correlated with the CURB-65 score of pulmonary infection (r = 0.696, 0.763, 0.851; all P < 0.001). The fatality rate of 182 patients was 17.03% (31/182). The proportion of ventilator application, tracheotomy and hypoproteinemia of death patients were higher than those of survival cases, and the age, levels of HMGB-1, RAGE, CRP and procalcitonin (PCT) were higher than those of survival group, with significant differences (all P < 0.05). Logistic regression analysis showed that age, proportion of ventilator application, tracheotomy, hypoproteinemia, HMGB-1, RAGE, CRP and PCT were all risk factors to death (OR = 2.016, 2.423, 2.252, 1.853, 2.606, 2.199, 1.919, 1.904, all P < 0.05). ROC analysis showed that the sensitivity of serum HMGB-1, RAGE and CRP in predicting the death of patients with pulmonary infection after brain trauma surgery were 78.02%, 82.42% and 85.16%, respectively, the specificities were 56.04%, 69.78% and 71.98%, respectively, while the area under AUC were 0.756, 0.801 and 0.882, respectively.

Serum HMGB-1, RAGE and CRP were positively correlated with the severity of lung infection after traumatic brain surgery, and were risk factors for death, which had a high clinical value for predicting death.