Equipment viva — the CRRT circuit and regional citrate anticoagulation

Stimulus

You are shown a schematic of a continuous venovenous haemodiafiltration circuit. Blood is drawn from a dual-lumen central venous catheter by a roller blood pump; a citrate infusion enters the pre-filter line; the blood passes through a hollow-fibre haemofilter where a dialysate runs counter-current and a replacement fluid is added (pre- and post-filter); the effluent (the spent dialysate plus the ultrafiltrate) drains to a bag; a calcium infusion is returned to the patient post-filter; and transmembrane and access pressures are displayed on the machine.^[1]