Independent control of blood gas PO2 and PCO2 in a bubble oxygenator.

An in-vitro circuit simulating cardiopulmonary bypass has been used to evaluate the gas transfer characteristics, gaseous microemboli production and blood damage of the Bentley-10 Plus bubble oxygenator. This oxygenator incorporates a unique integral gas controller which proportions the gas flow between the gas sparger and heat exchange area. The results of the study indicate that maintenance of a gas flow which ensures adequate CO2 removal can be prevented from inducing over-oxygenation by the manipulation of the gas controller which variably proportions the flow of gas from the oxygenation-efficient conventional gas sparger to the less efficient heat exchange area. Independent control of PaO2 with maintenance of CO2 transfer was demonstrated. Reduction in gaseous microemboli production and red blood cell damage with the use of the gas controller was demonstrated.