[1] During hemofiltration, a patient's blood is passed through a set of tubing (a filtration circuit) via a machine to a semipermeable membrane (the filter) where waste products and water (collectively called ultrafiltrate) are removed by convection.

Solutes, both small and large, get dragged through the membrane at a similar rate by the flow of water that has been engendered by the hydrostatic pressure.

Thus convection overcomes the reduced removal rate of larger solutes (due to their slow speed of diffusion) seen in hemodialysis.

[citation needed] Continuous hemofiltration (CHF) was first described in a 1977 paper by Kramer et al. as a treatment for fluid overload.

[8] However, a comprehensive analysis of audit data from intensive care units in the UK revealed that, compared with heparin, citrate-based drugs were not associated with fewer deaths among patients with acute kidney injury after 90 days of treatment.

These seminal papers represented the basis for the development of chronic hemodiafiltration by Leber and continuous arteriovenous hemofiltration (CAVH) by Peter Kramer.

[17] He used a hollow fiber “haemofilter” that originally designed as an alternative to HD for chronic renal failure and produced 300-600 ml/hour of ultrafiltrate by convection.

[19] He used a hollow fiber “haemofilter” that originally designed as an alternative to HD for chronic renal failure and produced 300-600 ml/hour of ultrafiltrate by convection.

Using an isotonic salt solution for fluid replacement, continuous arteriovenous hemofiltration (CAVH) was soon extended to the management of ARF.

In 1982, Kramer presented his experience with its use in more than 150 intensive care patients at a meeting of the American Society for Artificial Internal Organs(ASAIO).

[20] Before that, Henderson et al and Knopp, had studied hemofiltration in animals and as an alternative to dialysis in chronic renal failure, but it was really Peter Kramer’s report in ASAIO meeting in 1982 that stimulated many of nephrologists and intensivists to undertake the serious evaluation of CAVH in ARF in the ICU.

The low depurative efficiency was overcome by applying filters with two ports in the dialysate/filtrate compartment and through the use of counter-current dialysate flow, allowing the addition of diffusion and the birth of continuous arteriovenous hemodiafiltration or hemodialysis (CAVHDF or CAVHD).

[30] Information technology and precision medicine have recently furthered the evolution of CRRT, providing the possibility of collecting data in large databases and evaluating policies and practice patterns.

The opportunity to evaluate the endophenotype of the patient makes it possible to adjust treatments and techniques by implementing the concept of precision CRRT.

This allows clinicians to normalize outcomes and results among different populations or individuals and establish optimal and personalized care [31]