Impact of increasing post-filter ionised calcium target on regional citrate anticoagulation efficacy in ICU continuous renal replacement therapy: the non-inferiority randomised controlled Ca-CIBLE protocol

Continuous renal replacement therapy (CRRT) is a critical therapeutic intervention for patients with severe acute kidney injury in intensive care. However, premature filter clotting remains a significant challenge during CRRT, impacting treatment efficacy, costs and patient outcomes. Anticoagulation is essential to maintain circuit patency, with regional citrate anticoagulation (RCA) emerging as a preferred strategy due to its favourable bleeding profile. The standard target for post-filter ionised calcium (iCa) concentration during RCA-CRRT is set between 0.25 and 0.35 mmol/L, although evidence supporting this range is limited. We hypothesise that a higher post-filter iCa target (0.35-0.45 mmol/L) can provide comparable circuit patency while potentially reducing adverse effects associated with citrate administration.