Optimized Calcium Supplementation Approach for Regional Citrate Anticoagulation

Abstract

Background: It has been confirmed that regional citrate anticoagulation (RCA) plays an effective role in extracorporeal anticoagulation. The current trial-and-error calcium supplementation approach, with intensive monitoring of calcium levels, restricts the widespread use of RCA. Therefore, this study aimed to optimize the calcium supplementation approach for RCA. Methods: Patients requiring RCA treatment for various reasons were included. Citrate was infused into the arterial port, and the ionized calcium levels in the extracorporeal circulation tubes and body were monitored to maintain them within the target range. Linear regression equations between the clearance of non-protein bound calcium (n-Ca) and prescribed effluent rate were determined; the ratio of the n-Ca concentration to total calcium concentration (fa) after the infusion of citrate was also calculated. Then, we estimated a simplified calcium supplementation approach. Results: Positive correlations were found between the clearance of n-Ca and effluent rate both during continuous veno-venous hemodialysis (CVVHD) and continuous veno-venous hemofiltration (CVVH; R²: 0.66 and 0.65, respectively, p < 0.01). The fa values at the pre-filter point and after infusion of citrate were constants, but the values differed from CVVHD to CVVH. For CVVHD, fa was 0.93, and for CVVH, fa was 0.80. Using the extracorporeal removal characteristics of n-Ca, the amount of extracorporeally removed calcium per mmol per hour can be quantified with a simplified equation. Conclusion: The optimized calcium supplementation approach could provide a more precise and practical method to estimate the amount of extracorporeal calcium removal with regard to different modalities and dosages of RCA.