Evaluation of a screen oxygenator suitable for small animal organ perfusion

A small vertical screen oxygenator was built using a stainless steel screen enclosed in a Plexiglas box as the oxygenating surface. The unit was primed with 35 ml dextran-diluted blood (Hct 25.1 +/- 0.6%. mean +/- SE) and tested in cats with a partial cardiopulmonary bypass circuit. An oxygen saturation of more than 95% was always obtained, even when the incoming venous saturation was as low as 15%. The O2 exchange capacity was minimally affected by changes in blood flow (1.5 to 70 ml/min) through the unit. CO2 extraction was not flow limited over the range tested. Output PCO2 was 33.3 +/- 0.6 mmHg and pH was 7.29 +/- 0.02. These results were obtained when 3% CO2 in O2 was passed through the oxygenator chamber at 1.0 to 5.0 l/min. The performance of the unit was stable for periods up to 4 h. The small priming volume and reliable performance make this oxygenator suitable for organ perfusion in small experimental animals.