Abstract
Hemoconcentrator is an essential instrument for open heart surgery without blood transfusion. For simplifying the extracorporeal blood circuit and for an easy handling of cardiopulmonary bypass, we have developed a new membrane oxygenator with a function of hemoconcentrator by coupling a hollow-fiber unit for gas exchange and that for hemofiltration in one component. In a cylindrical housing, a set of hollow-fiber for hemofiltration was incorporated longitudinally, and outside of it, another set of hollow-fiber for gas exchange was located. Both of these units employed the blood outside perfusion system, and these were connected in series. Blood enters and flows through the central lumen for hemofiltration and then flows into the oxygenator. With adjusting the flow mode into the module by rearranging hollow-fibers to avoid mutual drag, improved performance was developed by increasing effective surface area. Oxygen transfer rate was 336ml/min at a flow rate of 6L/min, and ultrafiltration rate was 6.2L/hour with a flow rate of 4L/min with a hematocrit of 25%. No adverse effects were identified by coupling procedures. In conclusion, with coupling an oxygenator and a hemoconcen-trator, excellent and simplified hemoconcentration is readily available with this oxygenator due to the blood outside flow mode, which is also one of unique aspects of this device.
