ICU · Renal / RRT

CRRT — Circuit, Prescription, Anticoagulation & Troubleshooting

Also known as Continuous renal replacement therapy · CRRT circuit · CRRT prescription · CRRT anticoagulation · Citrate anticoagulation · Regional citrate · Filtration fraction · Pre-dilution · Post-dilution · CRRT troubleshooting · Circuit clotting · Access pressure · Transmembrane pressure

The CRRT is delivered through a blood circuit — the dual-lumen central access, the blood pump, the pre-dilution (the replacement fluid before the filter), the haemofilter (the hollow-fibre membrane), the post-dilution (the replacement fluid after the filter), the air-trap, and the return. The pressures (the access negative, the return positive, the filter transmembrane) monitor the circuit patency and the clotting. The prescription: the modality (the CVVH, the CVVHDF), the dose (the effluent 20 to 25 mL/kg/h), the blood flow, the fluid balance, the fluid composition, and the anticoagulation. The anticoagulation is the regional citrate (the preferred; the post-filter ionized calcium 0.25 to 0.35 mmol/L; the total-to-ionized ratio under 2.5; the risks the metabolic alkalosis, the acidosis in the liver failure, the hypercalcaemia) or the heparin or none. The troubleshooting: the circuit clotting (the inadequate anticoagulation, the high filtration fraction, the low blood flow), the high access pressure (the catheter kink or the position), the air-in-line, and the electrolyte and the nutrient loss (replace the K, the phosphate, the Mg, the increased nutrition).

Checked against its sources on 2 Sept 2026