Evaluation of circuit lifetime in continuous renal replacement therapy using two types of polysulfone membranes

For continuous venovenous hemofiltration (CVVH) to achieve an adequate therapeutic effect, prolonged stable administration and a long circuit lifetime are needed. The effects of hemofilters produced using various kinds of materials on circuit lifetime in CVVH have been examined, but no studies have investigated the effects of the length, diameter, or surface coating of hollow fibers. The aim of the present study was to evaluate the circuit lifetime in CVVH retrospectively using two types of polysulfone (PS) membranes. The participants were patients with acute kidney injury who underwent CVVH from January to July 2017 at a university hospital. The patients were divided into two groups based on the PS membrane used: an SHG group using Hemofeel® SHG (Toray Medical) and an AEF group using Excelflo® AEF (Asahi Kasei Medical). The SHG hemofilter has a longer and thinner hollow fiber than the AEF hemofilter. The target CVVH duration was 48 h. Circuit lifetime was defined as the time until a CVVH malfunction was identified. A CVVH malfunction was defined as a problem in extracorporeal circulation or either a 100-mmHg increase in the inlet chamber pressure or a 50-mmHg decrease in the filtration chamber pressure from baseline. During CVVH, the transmembrane pressure (TMP) change rate from baseline (at 0.5 h after initiation) was monitored. The SHG and AEF groups comprised eight and nine patients and underwent 10 and 14 sessions, respectively. No significant differences were seen between groups in patient characteristics or blood or filtration flow rate during CVVH. Although circuit lifetime tended to be longer in the SHG group, no significant differences in circuit lifetime were found between the two groups. The TMP change rate at 12 h after CVVH and thereafter was significantly higher in the AEF than that in the SHG group. In spite of using the same material, differences in the shape of the hollow fibers and surface treatment of the membrane affected the TMP change rate during CVVH in critically ill patients. To maximize circuit lifetimes, hemofilters should be chosen based on not only their materials but also their shape and membrane surface treatment. The patients in this study were registered retrospectively. Registered 12 July 2018 ( 302-54 ).