A comparison of gaseous emboli release in five membrane oxygenators

The purpose of this study was to compare the air handling capability of five currently used membrane oxygenators: the Avecor Affinity (TM), the Bentley (R) SpiralGold (TM), the Medtronic Maxima Plus (TM), the Sarns Turbo (TM) and the Sorin Monolyth (TM) M. A circuit was constructed to include a hardshell venous reservoir and roller pump. Pressure monitoring sites and ultrasonic microbubble detection probes were located proximal and distal to the oxygenator. An air injection/infusion site was provided proximal to the roller pump inlet. Each circuit was primed with fresh anticoagulated bovine blood, adjusted to a haematocrit of 25% and maintained at 38 +/- 1 degrees C. Three different bolus amounts of air (10, 20 and 40 cm(3)) were injected at three blood flow rates (3, 4.5 and 6 l/min). A 1-min infusion of air delivered at 1 ml/s was also administered at three blood flow rates (3, 4.5 and 6 l/min). The hardshell reservoir was also completely emptied at each flow rate to simulate a massive air infusion.