[Serum procalcitonin in patients with pulmonary infection and central nervous system injury]

Objective: To evaluate the influence of serum procalcitonin in the diagnosis and treatment of pulmonary infection in patients with central nervous system injury. Methods: From October 2014 to February 2017, a retrospective study was performed. A total of 1 852 patients were screened in Department of Intensive Care Unite, First Affiliated Hospital of Sun Yat-sen University.Among them, 173 patients were identified with different kinds of infection. Finally, a total of 42 patients with pulmonary infection were enrolled. The clinical data of patients with pulmonary infection and central nervous system (CNS) injury was collected. A univariate and multivariate regression analysis was performed to study the correlation of serum procalcitonin (PCT) with clinical symptoms and signs of the pulmonary infection, body temperature(T), white blood cell count (WBC), percentage of neutrophils (NEU) and the severity of the pulmonary infection (CPIS). The relationship of serum PCT with type of CNS injury, GCS, and exogenous glucocorticoid was further studied. Results: During the period of pulmonary infection, the peak PCT was 0.83 (0.29, 2.79) μg/L and the CPIS was 5.50 (5.00, 7.00). In 9 of 42 patients, the peak PCT was less than 0.25 μg/L. In 7 of 42 patients, the peak PCT was ranged from 0.25 to 0.5 μg/L. In 12 of 42 patients, PCT was ranged from 0.5 to 2 μg/L. Only 10 patients had a PCT 2-10 μg/L and 4 patients had a PCT more than 10 μg/L. There is no correlation between serum PCT and body temperature, white blood cell, percentage of neutrophils and CPIS. There was no significant differences in patients with PCT<0.5 or ≥0.5 μg/L regarding the body temperature, white blood cell, percentage of neutrophils and CPIS. However, serum PCT in patients with pulmonary infection had independent correlation with the post CNS injury day (β=0.17, 95% CI (0.02, 0.32), P<0.05). The serum PCT was 1.26 (0.47, 2.7) μg/L and 29.41% patients with a PCT less than 0.5 μg/L within 3 days post CNS injury. Serum PCT level was 0.23 (0.16, 0.39) μg/L, and 77.78% patients with a PCT less than 0.5 μg/L at day 4 to day 7 post-injury. The PCT level was 0.52 (0.33, 1.12) μg/L, and 44.44% patients with a PCT less than 0.5 μg/L at day 8 to day 14. The PCT was 3.26 (2.07, 12.40) μg/L, and no patient with a PCT less than 0.5 μg/L after day 15 post-injury. There were no significant relationship found between serum PCT level and type of the disease and surgery, GCS, and use of exogenous glucocorticoid. Conclusions: Serum PCT had no significant increase and was not able to be used in guiding the antibiotics use in patients with CNS injury and pulmonary infection.