Profound hypocalcaemia in a patient being anticoagulated with citrate for continuous renal replacement therapy

Abstract

SummaryCitrate, as an anticoagulant for continuous renal replacement therapy in critically ill patients, has some potential advantages over heparin, including a prolonged dialysis filter life and reduced risk of bleeding. The key parameter involved in monitoring the adequacy and safety of citrate anticoagulation during continuous renal replacement therapy pertains to the ionised and total plasma calcium levels. We report a case of severe systemic hypocalcaemia during continuous renal replacement therapy with citrate anticoagulation resulting from relentless sequestration of calcium due to undiagnosed evolving rhabdomyolysis. Although excessive systemic citrate accumulation can also cause hypocalcaemia, this complication was not observed in our patient. While an acceptable lower limit of ionised calcium remains unknown, severe rhabdomyolysis needs to be considered when a patient's ionised calcium levels are not responsive to standard calcium replacement therapy during continuous renal replacement therapy using citrate anticoagulation in critically ill patients.

Regional Citrate Anticoagulation for RRTs in Critically Ill Patients with AKI

“…Specific clinical situations, such as severe rhabdomyolysis, can potentially complicate the management of serum ionized calcium concentrations during RCA (22,37). Although hypocalcemia is a common complication in the early phase of rhabdomyolysis, full correction of calcium levels is not recommended because of potentially harmful effects of excessive calcium supplementation (e.g., tissue calcium deposition and episodes of late hypercalcemia) (38).…”

“…Although hypocalcemia is a common complication in the early phase of rhabdomyolysis, full correction of calcium levels is not recommended because of potentially harmful effects of excessive calcium supplementation (e.g., tissue calcium deposition and episodes of late hypercalcemia) (38). Thus, a lower than usual systemic ionized calcium level (0.9-1 mmol/L) should be considered a reasonable target while performing RCA CRRT in this clinical scenario (22,37).…”

Patient Factors Associated with Frequent Clotting of Dialysers during Haemodiafiltration in Critically Ill Patients: A Post Hoc Analysis of a Randomised Controlled Study

“…Clotting of dialysers during CVVHDF increases patient blood loss, workload of intensive care unit nurses and cost of dialysis, as well as reducing efficiency of dialysis 3,5 . Although regional citrate dialysis appears to be effective in reducing frequency of clotting of dialysers during CVVHDF 12 , the circuit is relatively more complicated to initiate than the traditional CVVHDF circuit, and vigilant monitoring of electrolyte concentrations, in particular plasma calcium concentration, is essential to avoid major complications 13,14 . Full systemic anticoagulation is also more effective than low-dose anticoagulation during CVVHDF to reduce clotting of dialysers, but it is associated with an increased risk of bleeding.…”