Zheng Y, et al. - Researchers sought to identify the determinants of calcium requirements in regional citrate anticoagulation (RCA)-CVVH and to simplify the calcium supplementation approach. They conducted this study in two parts. In the first part, the key factors of calcium supplementation were determined to propose a two-phase calcium supplementation protocol, and develop algorithms for calcium supplementation. The second part of the study was the validation phase. As per findings, the main determinants of the required calcium supplementation comprised the loss of calcium flux in the extracorporeal circuit and the increase in citrate-calcium complexes in vivo. In the CVVH mode, reduction in the rate of calcium infusion was suggested after systemic citrate level reached a steady state. Using mathematical models, systemic calcium levels could be stably maintained in the normal range, and reduction in the frequencies of calcium monitoring is observed.