Evaluation of the Quadrox-I neonatal oxygenator with an integrated arterial filter

Cardiopulmonary bypass (CPB) can be a potential cause of morbidity in patients for several reasons, including significantly higher gaseous microemboli (GME) formation than extracorporeal life support (ECLS) and physiological circulation, diverted blood flow from the patient via an open purge line of the arterial filter, and pressure drop across the oxygenator that is used in the circuit. Using a combined oxygenator and arterial filter may minimize these harmful factors and can effectively reduce the chances for postoperative morbidity. This study investigated the new QUADROX-i Neonatal Oxygenator (D-72145, Maquet, Hirrlingen, Germany) with an integrated arterial filter in terms of the hemodynamic properties and ability to clear GME in response to hypothermic versus normothermic conditions, open versus closed arterial filter purge line, and varying flow rates in a simulated CPB circuit identical to that of the clinical setting. A flow probe, pressure transducer, and Emboli Detection and Classification (EDAC) quantifier transducer were placed upstream and downstream to the oxygenator to measure changes in each parameter. The circuit was primed with fresh human blood with an hematocrit (Hct) of 26% diluted with Ringer's lactate solution. Five milliliters of air were injected proximal to the venous cardiotomy reservoir, under non-pulsatile perfusion, with flow rates of 500 ml/min, 750 ml/min, and 1000 ml/min. A total of 8 air bolus injections were made at each individual set of conditions for a total of 96 injections. Results showed that the QUADROX-i Neonatal Oxygenator with an integrated filter has excellent hemodynamic properties with extremely low pressure drops and blood flow diverted from the patient, as well as high rates of GME capturing. The arterial filter purge line has a significant effect on the degree of blood flow diverted from the patient (p < 0.001), but does not affect pressure drop across the oxygenator.