Impact of increasing post-filter ionized calcium target on filter lifespan in renal replacement therapy with regional citrate anticoagulation: A before-and-after study

Introduction: Regional citrate anticoagulation (RCA) is the recommended method for anticoagulation in contin-uous renal replacement therapy (CRRT). However, the optimal post-filter ionized calcium (iCa) target level re-mains unclear. This study aims to assess the effect of increasing the post-filter iCa target level from 0.25-0.35 mmol/L to 0.30-0.40 mmol/L on filter lifespan until clotting during RCA-CRRT.Methods: This before-and-after single-center study included patients who underwent RCA-CRRT sessions without systemic anticoagulation during two periods. The first period included patients with a post-filter iCa target between 0.25 and 0.35 mmol/L, while the second period included those with a target between 0.30 and 0.40 mmol/L. The primary outcome was filter lifespan until clotting.Results: A total of 1037 CRRT sessions were analyzed, with 610 sessions in the first period and 427 sessions in the second period. After adjusting for confounding factors, there was no significant difference in filter lifespan until clotting between the two groups (hazard ratio, 1.020 [0.703; 1.481]; p = 0.92).Conclusion: Increasing the post-filter iCa target level from 0.25-0.35 mmol/L to 0.30-0.40 mmol/L during RCA-CRRT does not reduce filter lifespan until clotting and may decrease unnecessary citrate exposure. However, the optimal post-filter iCa target should be individualized according to the patient's clinical and biological status.