Online CHDF system: excellent cost-effectiveness for continuous renal replacement therapy with high efficacy and...

We developed an online continuous hemodiafiltration (CHDF) system with a central reverse osmosis (RO) fluid delivery system in 1996. This was improved to a system composed of a single-patient dialysis machine and RO module in 2003. This comprises a water treatment system, an RO module, a dialysis machine with 3 endotoxin retentive filters, 2 additional roller pump units, and a disposable special circuit. Dialysate is produced online by a dialysis machine using RO water and dialysate concentrate, which passes through endotoxin retentive filters and is supplied via the machine in the usual manner. A disposable special circuit and additional two roller pumps independently regulate dialysate flow and substitute flow from 0 to 12 in steps of 0.1 l/h. Seventy-seven patients with acute kidney injury (AKI) were treated with online CHDF from December 1996 to June 2004. Patient outcome was compared with the other modality of continuous renal replacement therapy from July 1992 to June 2004. The survival rates of each modality were 68.3, 65.0, 56.6 and 74.0% for conventional CHDF, high-flow continuous hemodialysis, high-flow CHDF and high-flow/high-volume CHDF (online CHDF), respectively. The survival rate of the high-volume modality (online CHDF) group was significantly higher (p = 0.046) than that of the low volume modality group (61.1%). Increases in efficacy and efficiency are a challenge facing blood purification therapy, and, moreover, individualized prescriptions are crucial in AKI patients in ICU. However, the cost of the dialysate and substitution fluid is a limitation of the therapy. The greatest advantage of the system is that a very high dose of delivered dialysate and substitute does not lead to a proportional rise in the cost. The online CHDF system is currently one of the most feasible solutions.