The aim of this study is to evaluate the effect of regional citrate anti-coagulation on different pathways of the coagulation system in critically ill patients with acute kidney injury. This will form the basis for future studies where the investigators plan to focus on patients with premature circuit clotting despite optimal post-filtrate ionised calcium parameters.

Purpose of clinical trial:

To evaluate the effect of regional citrate anti-coagulation on different pathways of the coagulation system in critically ill patients with acute kidney injury.

Patient population:

critically ill patients with acute kidney injury requiring citrate-based continuous renal replacement therapy (CRRT)

Primary objective:

Changes from baseline in a number of measures of coagulability (platelet count; Prothrombin Time; Activated Partial Thromboplastin Time ratio; fibrinogen; d-dimers; Thrombin generation assay; Clot lysis; platelet function analysis 100) in both the blood within the patient's systemic circulation and the CRRT circuit over the course of 72 hours of regional anticoagulation with citrate.

Number of Subjects/Patients:

12 patients with complete data.

Trial Design:

Prospective non-interventional study.

Endpoints:

Change from baseline in a number of measures of coagulability.

Main Inclusion Criteria:

Adult intensive care patients undergoing CRRT with citrate regional anti-coagulation for AKI.

Inclusion criteria:

• acute kidney injury treated with citrate based continuous renal replacement therapy (CRRT)
• age >18 years.
• expected to require >72 hours of CRRT.

Exclusion criteria:

• Known preexisting clotting tendency
• Known preexisting bleeding tendency
• Disseminated Intravascular Coagulation (DIC)
• Prior transfusion of any blood product in the 24 hours before enrolment
• Active bleeding (ie. needing blood transfusion) at time of enrolment
• Haemoglobin at time of enrolment <75g/L
• Haematocrit at time of enrolment >0.55
• Patient would refuse Red Blood Cell transfusion (for example Jehova's Witness).
• Platelet count at time of enrolment <100x103/µL
• Treatment with any anticoagulant or antiplatelet agent at time of enrolment or within 7 days of enrolment with the exception of heparin or low molecular weight heparin for DVT prophylaxis.
• Intravenous heparin exposure within 4 hours of commencing citrate anticoagulation.
• Malnourished: BMI <18.5kg/m2 or unplanned weight loss >10% actual body weight (ABW) in preceding 6 months or BMI <20kg/m2 and unplanned weight loss >5% ABW in preceding 6 months.
• CRRT prescribed for an indication other than AKI (for example poisoning).

adults with acute kidney injury requiring citrate based continuous renal replacement therapy