A Prospective Randomized Study of Membrane versus Bubble Oxygenators in Children

We studied 60 children, 2 weeks to 10 years old, prospectively by randomly assigning them to a SciMed membrane oxygenator or Harvey bubble oxygenator. Variables of cardiopulmonary bypass (CPB) were closely controlled: prime, circuit configuration, flow rate, and blood gases. Blood variables measured at eight intervals before, during, and after operation were as follows: seven plasma proteins, free hemoglobin, formed elements, and clotting functions. Preoperatively and postoperatively, we evaluated brain function (psychological testing), renal function (creatinine clearance), and pulmonary function (compliance changes and postoperative shunt fraction). Postoperative blood loss, fever, and length of hospitalization were also evaluated. We compared 302 variables by computer program.No difference (p > 0.05) between the two groups was found in any variable related to CPB or organ function (pulmonary, renal, or cerebral) or in hematological variables except free hemoglobin. After 5 and 60 minutes of CPB and the next day, it was significantly lower (p < 0.05) in the group with a membrane oxygenator. Safety, cost, and convenience, not physiology, should be the major factors in considering membrane versus bubble oxygenators for cardiac operations in children.