DEVELOPMENT OF AN INTRAVENOUS MEMBRANE-OXYGENATOR - ENHANCED INTRAVENOUS GAS-EXCHANGE THROUGH CONVECTIVE MIXING OF BLOOD AROUND HOLLOW-FIBER MEMBRANES

In vitro testing of a new prototype intravenous membrane oxygenator (I MO) is reported. The new IMO design consists of matted hollow fiber me mbranes arranged around a centrally positioned tripartite balloon. Sho rt gas flow paths and consistent, reproducible fiber geometry after in sertion of the device result in an augmented oxygen flux of up to 800% with balloon activation compared with the static mode (balloon off). Operation of the new IMO device with the balloon on versus the balloon off results in a 400% increase in carbon dioxide flux. Gas flow rates of up to 9.5 L/min through the 14-cm-long hollow fibers have been ach ieved with vacuum pressures of 250 mm Hg. Gas exchange efficiency for intravenous membrane oxygenators can be increased by emphasizing the f ollowing design features: short gas flow paths, consistent and reprodu cible fiber geometry, and most importantly, an active means of enhanci ng convective mixing of blood around the hollow fiber membranes.