Abstract:

Objective To observe the changes of coagulation function in elderly patients with severe pneumonia infected by different Gram-negative bacteria，and to provide a reference for clinical diagnosis and treatment. Methods A total of 197 elderly patients with severe pneumonia in Dongzhimen Hospital of Beijing University of Chinese Medicine from September 2019 to September 2022 were enrolled. Before the treatment with antibacterial drugs，the sputum samples were taken for pathogen culture. The coagulation function was determined. The differences in coagulation function indicators [activated partial thromboplastin time（APTT），prothrombin time（PT），thrombin time（TT），D-dimer（DD），plasma fibrinogen（Fib）] were compared between patients infected with Gram-negative bacteria and those infected with Gram-positive bacteria. Based on the disease outcome，patients infected with Gram-negative bacteria were classified into poor and good prognosis groups. The differences in coagulation function among patients infected with different Gram-negative bacteria were compared. The differences in coagulation function among patients with severe pneumonia infected by Gram-negative bacteria with different prognoses were evaluated. Results Among the 197 patients，110（55.84%）cases were infected with Gram-negative bacteria. The APTT of patients infected with Gram-positive bacteria was shorter than that with negative sputum culture，and the DD level was higher（P<0.05）. The APTT and PT of patients infected with Gram-negative bacteria were shorter than those with negative sputum culture and Gram-positive bacteria，while the DD and Fib levels were higher than those with negative sputum culture and Gram-positive bacteria（P<0.05）. The APTT and PT of patients infected with Acinetobacter baumannii were shorter than those of patients infected with other types of Gram-negative bacteria，while the levels of DD and Fib were higher than those of patients infected with other types of Gram-negative bacteria（P<0.05）. The APTT and PT in poor prognosis group were shorter than those in good prognosis group，and the levels of DD and Fib were higher than those in good prognosis group（P<0.05）. Conclusions Elderly patients with severe pneumonia infected by Gram-negative bacteria have coagulation dysfunction，and the coagulation dysfunction is more obvious in patients infected with Acinetobacter baumannii. There is a certain relationship between poor coagulation function and poor prognosis of patients.

Key words: Coagulation function, Severe pneumonia, Elderly, Gram-negative bacterium