Intensive monitoring of post filter ionized calcium concentrations during CVVHD with regional citrate anticoagulation: A retrospective study

The aim of the present study was to assess the predictive value of post-filter ionized calcium (pfCa) levels for filter-clotting during continuous veno-venous hemodialysis (CVVHD) with regional citrate anticoagulation (RCA). Retrospective analysis of a database derived from 6 intensive care units (ICU) at a university hospital. During the 3-year period 1070 patients were treated with RCA-CVVHD with a citrate starting dose of 4 mmol/L blood and a target-range for pfCa of 0.25–0.35 mmol/L. The pfCa concentrations at RCA-CVVHD initiation were within the target range in 69.7% of patients. Within 12 h the fraction of patients with pfCa above target-range decreased significantly from 13.1% to 7.8% (p < .001). There was no significant difference in filter survival between patients with a pfCa initially below, within, or above the target-range (83.7%, 89.5% and 90.4%; p = .228) and no significant correlation between the last pfCa and the incidence of filter clotting (rho 0.018, p = .572 and −0.054, p = .104; respectively). CVVHD with a citrate starting dose of 4 mmol/L blood resulted in a pfCa within target in the majority of patients. The observation that pfCa was not associated with the incidence of circuit clotting suggests that less frequent measurements of pfCA might be safe.