Clinical Study on Monitoring the Plasma Concentration of Ceftazidime-Avibactam in Critically Ill Patients

Patients with severe sepsis and treatment with CAZ-AVI will be enrolled. Blood samples at 0 hour, 2 hours, 4 hours, 6 hours, and 8 hours after the first time and the steady state concentration(more than 4 times drug administration) of drug administration will be collected to detect plasma drug concentrations of CAZ-AVI