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.

INTRODUCTION: 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.

METHODS AND ANALYSIS: This multicentre randomised controlled non-inferiority trial will compare a low post-filter iCa target (0.25-0.35 mmol/L) with a higher post-filter iCa target (0.35-0.45 mmol/L) in patients undergoing RCA-CRRT in the intensive care unit. A total of 412 CRRT sessions will be randomised with a 1:1 ratio into these two groups. The primary outcome is the incidence of filter clotting. Secondary outcomes include filter lifespan, post-filter iCa levels, citrate infusion rates, the occurrence of metabolic adverse effects, financial costs and blood loss.

ETHICS AND DISSEMINATION: The study has obtained approval from the ethics committee (Ethics Committee Est III, Nancy, France) and patients will be included after providing informed consent. The results will be disseminated at academic conferences and in peer-reviewed publications. All procedures were developed in order to assure data protection and confidentiality.

TRIAL REGISTRATION NUMBER: NCT05814341.