The CVVHDF circuit has been asked about in Question 30 from the second paper of 2014 and Question 2d from the second paper of 2001, but the HF (haemofiltration) circuit had been left out of the question papers until Question 26 from the first paper of 2018. Given that most modern machines perform CVVHDF, it seemed unlikely that this would ever come up, but come up it did. Moreover, the college presented us with a decent quality diagram of the circuit, which will forevermore be the definitive diagram. This is presented below, together with the low-budget local version.
This alternative diagram was adopted from the Gambro Prismaflex brochure. It varies from the official college diagram by the way the anticoagulant syringe drivers and pressure gauges are positioned in the circuit.
For the dialysis enthusiast, in vivo anatomy of the CRRT circuit is explored in greater detail in a chapter elsewhere.
If one were to reproduce such a diagram in the college SAQs, one's diagram would be expected to " be appropriately labelled and depict access and return lines, filter, dialysate, effluent and replacement fluid and include sites of pressure measurement and pumps".