Table 1 Main disposables and their components with associated color code in a CRRT extracorporeal circuit (modified from [45])

 Blood in-flow line (red; previously known as access or arterial line)

Segment connecting the patient’s vascular access to the filter

Segment for pressure measurement (upstream blood pump): segment of the blood in-flow line connected to the in-flow pressure sensor

Pump segment line: segment inserted between the rotor and the stator of the blood pump

Blood in-flow air removal chamber: allows removal of light air bubbles before the blood enters the filter

Segment for pressure measurement (downstream blood pump): segment of the blood in-flow line connected to the pre-filter pressure sensor

 Blood out-flow line (dark blue; previously known as return or venous line)

Segment connecting the filter to the patient’s vascular access

Segment for pressure measurement: segment of the blood out-flow line connected to the out-flow pressure sensor

Blood out-flow air removal chamber: allows removal of light air bubbles before the blood returns to the patient

 Effluent/ultrafiltrate line (yellow)

Segment that allows the flow of waste fluids from the filter

Pump segment line: segment inserted between the rotor and the stator of the effluent/ultrafiltrate pump

Segment for pressure measurement: segment of the effluent line connected to the effluent/ultrafiltrate pressure sensor

 Dialysate line (green)

Segment that allows the flow of incoming dialysate into the filter

Pump segment line: segment inserted between the rotor and the stator of the dialysate pump

Segment for pressure measurement (if present): segment of the dialysate line connected to the dialysate pressure sensor

Heater line: segment of the dialysate line placed in contact with the heater

 Replacement line (purple or light blue)

Segment that allows the flow of replacement fluid into the blood in-flow and/or blood out-flow lines

Pump segment line: segment inserted between the rotor and the stator of the replacement pump

Segment for pressure measurement (if present): segment of the replacement line connected to the replacement pressure sensor

Heater line: segment of the replacement line placed in contact with the heater

 Pre-blood line (orange)

Segment that allows the flow of specific fluids (mainly regional anticoagulants) into the blood in-flow line before the blood pump

Pump segment line: segment inserted between the rotor and the stator of the pre-blood pump

Segment for pressure measurement (if present): segment of the pre-blood line connected to the pre-blood pressure sensor

 Anticoagulant and specific antagonists line

Segments connecting the anticoagulant/specific antagonist bag or pump to the main blood circuit

Citrate line (orange): segment for citrate infusion (i.e., pre-blood line)

Heparin line (white): segment connecting the heparin syringe pump to the blood in-flow line

Specific antagonist line (black): segment connecting the specific antagonist syringe pump to the blood out-flow line

 Fiber (membranes)

Every fiber, hollow and of cylindrical shape, allows the transport of fluids and solutes through their porous semi-permeable surface

 Bundle

Entire number of fibers inside the housing

 Housing

Plastic casing containing a single membrane fiber bundle

Blood in-flow port: entrance port of blood entering into the filter

Blood out-flow port: exit port of blood leaving the filter

Dialysate in-flow port: entrance port of fresh dialysate

Effluent/ultrafiltrate out-flow port: exit port of waste solution

 Potting

Polyurethane component fixing the bundle within the housing and embedding the bundle at both ends of the filter