The pumping oxygenator: Design criteria and first in vitro results

A new project is presented, the pumping oxygenator, functionally integratin g pulsatile pumping and blood oxygenation in a single device. Solid, semipe rmeable silicone membranes allow gas exchange and simultaneously transfer e nergy from pressurized gas to blood thanks to their distensibility and to i nlet and outlet 1-way valves. Two small-sized (1 m(2) exchange surface area ) prototypes were designed, constructed, hydraulically characterized, and s ubjected to gas transfer evaluation tests. Blood flow rates (Q(b)) up to 1, 250 ml/min were obtained with 30 mm Hg static preload and 130 mm Hg afterlo ad with 0.7 m upstream and 2.1 m downstream 3/8 inch pipes. Physiological o xygen transfer ((V)over dot O-2 = 5 ml/dl, mi of transferred O-2/dl of trea ted blood) was delivered at Q(b) < 900 ml/min, about 4 ml/dl at Q(b) = 1,25 0 ml/min. (V)over dot O-2 also was significantly increased by increasing pe rcent systolic time. CO, transfer decreased regularly with increasing Q(b) from (V)over dot CO2, = 4.8 ml/dl at Q(b) = 400 ml/min to (V)over dot CO2 = 2.1 ml/dl at Q(b) = 1,250 ml/min. The results confirm the possibility of i ntegrating oxygenation and pulsatile pumping. The pumping oxygenator repres ents a promising project deserving further improvements.