Impact of post-filter ionized calcium target range on circuit survival and citrate-related complications in pediatric...

Regional citrate anticoagulation (RCA) is the preferred strategy for continuous kidney replacement therapy in children; however, the optimal post-filter ionized calcium target remains uncertain. Lower targets may increase anticoagulation but raise citrate exposure and metabolic complications. We aimed to compare anticoagulation efficacy and metabolic safety between a low-target (0.25-0.35 mmol/L) and a high-target (0.30-0.40 mmol/L) post-filter ionized calcium protocol in critically ill children.

This retrospective cohort study included critically ill children receiving continuous veno-venous hemodiafiltration with citrate as the pre-filter anticoagulation solution at a tertiary pediatric intensive care unit over a 4-year period. A total of 87 patients (42 low-target, 45 high-target) and 154 circuits (71 versus 83) were analyzed. The primary outcome was circuit survival (CS). Secondary outcomes included citrate dose, citrate load, and RCA-related complications. Continuous variables were analyzed using the Mann-Whitney U test, and CS was assessed with Cox regression. Linear mixed models evaluated citrate changes, and generalized estimating equations analyzed metabolic outcomes.

Median CS was comparable between groups (49 versus 48 h, p = 0.76) as was the survival of clotted circuits (41 versus 40 h, p = 0.70) and circuit clotting rates were similar (21.1% versus 24.1%, p = 0.70). The low-target group had higher median citrate dose (2.9 versus 2.6 mmol/L, p < 0.001), citrate load (0.76 versus 0.72 mmol/kg/h, p = 0.03), and more frequent hypocalcemia (17.5% versus 12.9%, p = 0.01), metabolic alkalosis (31.9% versus 22.8%, p < 0.001), and citrate accumulation (24.5% versus 15.4%, p < 0.001). Linear mixed models showed a persistently higher citrate dose and citrate load in the low-target group (all p < 0.001). Generalized estimating equations demonstrated increased odds of hypocalcemia (odds ratio 1.47, p = 0.01) and citrate accumulation (odds ratio 1.93, p < 0.001) in the low-target group.

Raising the target of post-filter ionized calcium from 0.25-0.35 to 0.30-0.40 mmol/L reduced citrate exposure and metabolic complications without compromising CS.

Retrospectively registered.