[Influence of post-filter ionic calcium gradients on the longevity of CRRT local citrate anticoagulation in extracorporeal circulation].

Objective: To investigate the influence of different post-filter ionic calcium (Ca2+) gradients (0.25-0.35 mmol/L vs>0.35-0.50 mmol/L) on the extracorporeal lifetime of local citrate anticoagulation (RCA) for continuous renal replacement therapy (CRRT). Methods: Patients who underwent CRRT with RCA at West China Hospital of Sichuan University from March 2021 to June 2022 were retrospectively selected. The basic information and the values of post-filter Ca2+at 0, 2, and 6 hours after the start of treatment and every 6 hours thereafter were collected. The patients were divided into low concentration group (0.25-0.35 mmol/L mmol/L) and high concentration group (>0.35-0.50 mmol/L) according to the mean value of Ca2+concentration per treatment, and propensity score matching was performed in a 1∶1 ratio to evaluate the effect of post-filter [iCa2+] on the duration of extracorporeal circulation in different groups. Results: A total of 232 patients (147 males and 85 females) aged (58.2±16.9) years were enrolled. There were 431 cases treated with CRRT for 12 592 h, including 317 cases (73.5%) in the low concentration group and 114 cases (26.5%) in the high concentration group. The baseline data of the two groups were matched and analyzed. Coagulation events occurred in 54.9% (62/113) and 54.0% (61/113) in the low and high concentration groups, respectively (P=0.894). The median survival on extracorporeal circulation was 65.0 (29.0, 72.0) h and 68.0 (31.5, 72.0) h in the two groups, respectively (P=0.805). Multivariate Cox regression analyses showed that post-filter [iCa2+] had no effect on extracorporeal life expectancy (HR=0.99, 95%CI:0.55-1.79). Conclusion: During CRRT treatment with RCA, the desired anticoagulant effect can still be achieved when the post-filter [iCa2+] target was set to 0.25-0.50 mmol/L.