Troubleshooting Ionized Hypocalcemia in Patients on Continuous KRT with Regional Citrate Anticoagulation

Regional citrate anticoagulation (RCA) is the preferred anticoagulation method in continuous KRT (CKRT), provided its use is feasible without causing excessive systemic citrate accumulation. One significant concern with RCA is ionized hypocalcemia related to the CKRT procedure. This condition can arise from two primary causes: systemic citrate accumulation or net calcium loss from plasma. Systemic citrate accumulation occurs when the citrate load in the CKRT return blood exceeds the body's ability to metabolize it. On the other hand, net calcium loss occurs when calcium lost through the hemofilter and from the extracellular fluid space (due to tissue sequestration) exceeds the administered calcium supplementation. This case-based review outlines RCA-associated hypocalcemia and provides a framework for its evaluation and management at the bedside.