Abstract: Objective  This retrospective study aimed to identify factors contributing to clotting within 48 hours in circuits of continuous renal replacement therapy (CRRT) using regional citrate anticoagulation (RCA). Methods  Data from the intensive care unit of the Second Affiliated Hospital of Guangzhou Medical University between June 2021 and July 2023 were analyzed. Circuits were categorized into clotting and non-clotting groups based on 48-hour clotting occurrence. COX regression analysis was performed to identify clotting risk factors. Results A total of 114 patients with 179 sets of CRRT circuits and corresponding data were included in the study. Among them, clotting within 48 hours of initiation was observed in 105 cases, while 74 cases did not experience clotting within 48 hours. Venous pressure (HR=1.008, 95% CI: 1.0～1.016, P=0.045)and lactate level ≥2 mmol/L (HR=1.517, 95% CI：1.009～2.280, P=0.045) were identified as independent risk factors for circuit clotting within 48 hours of CRRT. On the other hand, citrate dose ≥3.2 mmol/L (HR=0.461, 95% CI：0.312～0.682, P＜0.001) was identified as a protective factor. Conclusion  In continuous renal replacement therapy using regional citrate anticoagulation, high venous pressure, increased platelet count, and elevated lactate levels were associated with increased clotting risk within 48 hours. Pre-filling circuits adequately and optimizing catheter positioning before CRRT initiation are recommended. Managing patients with high lactate levels and impaired tissue perfusion through fluid resuscitation can reduce clotting risk.

Key words: Regional citrate anticoagulation, Continuous renal replacement therapy, Clotting, Lactate