Abstract
In order to simplify the extracorporeal blood circuit and to facilitate handling of cardiopulmonary bypass, we have combined ahollow fiber unit for gas exchange and that for hemofiltration in one component and developed a new membrane oxygenator with a function of hemoconcentrator. The cylindrical device is consisted of a hollow fiber for hemofiltration with another fiber for gas exchange provided outside. Both of them adopt the blood outside perfusion system. Blood flows from around the center core towards the hollow fiber around it, first hemoconcentrator and then oxygenator, in radial direction. By applying this flow mode, even distribution of blood flow to the entire fiber was realized and the performance of the device was improved. Oxygen transfer rate was 336ml/min at a flow rate of 6L/min, and ultrafiltration rate was 7L/ hour with a flow rate of 4L/min with a hematocrit of 25%. Pressure drop of the whole unit was only 60mmHg with a flow rate of 6L/min. The combined structure of the two units has not caused any adverse effects. In conclusion, by combining an oxygenator and a hemoconcentrator, excellent and simplified hemoconcentration is made available as the blood outside flow mode is adopted.
