Abstract: Objective  To explore the application of respiratory variability of inferior vena cava diameter for early volume management of continuous renal replacement therapy (CRRT) in sepsis shock patients.   Methods The sepsis patients hospitalized in the Intensive Care Unit (ICU) of the Second Hospital of Jiaxing City and planned to be treated with CRRT were selected as the research objects. They were randomly divided into control group and ultrasound group. In the ultrasound group, the respiratory variation rate of inferior vena cava diameter was monitored by ultrasound to guide fluid management during CRRT. General data of the patients were collected, and the hemodynamics and blood gas indexes of the two groups were compared before CRRT and 24, 48 and 72 hours after CRRT. Clinical prognosis indexes of the two groups were analyzed.   Result   A total of 60 patients were enrolled in this study, including 30 in the control group and 30 in the ultrasound group. There were no significant differences in the general clinical data between the two groups (P＞0.05). Compared with the control group, the dose of vasoactive drugs and the central venous pressure were lower (F=1.255 and 18.618, P＜0.001) in the early stage of CRRT of the ultrasound group. In addition in the ultrasound group, the prognostic indicators showed that the durations of CRRT and vasoactive drug treatment were shorter (t=3.103 and 4.775, P=0.004 and ＜0.001),  and the rate of withdrawal from CRRT at the 28th day was higher (χ2=4.593, P=0.032).  Conclusion  The use of ultrasound to monitor the respiratory variation rate of inferior vena cava diameter can guide the early volume management of CRRT in septic patients, so that the early hemodynamic indexes and the clinical prognosis are improved in these patients

Key words: Ultrasonic, Inferior vena cava, Sepsis, Continuous renal replacement therapy, Capacity