Evaluation of the Anticoagulant Effect of Effluent Ionized Calcium iCa to Measure Regional Citrate Anticoagulation (RCA) Performance vs. Post-filter Ionized Calcium iCa: A Single-Center Non-inferiority Randomized Controlled Trial (RCT)

Background: This study aimed to evaluate the feasibility of using effluent fluid instead of postfilter ionized calcium (iCa) measurements for assessing anticoagulation in continuous renal replacement therapy (CRRT) with regional citrate anticoagulation in critically ill patients. Using citrate in CRRT is to prevent clotting within the circuit by chelating calcium, which is essential for the coagulation cascade. Methods: A two-arm, parallel, placebo-controlled, single-center RCT was conducted to assess and compare the efficacy and safety of different target ranges of effluent fluid ionized calcium and post-filter ionized calcium in continuous renal replacement therapy (CRRT) with regional citrate anticoagulation Results: In total, 11 critically ill patients with 91 paired samples of CVVHDF with a mean age of 57.7 and a male-to-female ratio of 7:4. The mean post-filter ionized calcium was 0.28 ± 0.12 mmol/L, and the mean ionized calcium level of effluent fluid was 0.33 ± 0.11 mmol/L. r = 0.631, P value = 0.03, which is statistically significant, i.e., P<0.05. Bland-Altman analysis showed that the mean difference of ionized calcium between two sampling sites in continuous renal replacement therapy patients was -0.06 mmol/L with a 95% confidence interval ranging from -0.18 to 0.007 mmol/L. Conclusion: Our results suggested there was a significant correlation between the two sampling points, and we explored the possibility of using effluent fluid for iCa measurements instead of postfilter iCa.Bland-Altman analysisPearson correlation analysis