A mathematical model to predict CO2 removal in hollow fiber membrane oxygenators.

A mathematical model has been developed to predict CO(2) removal in hollow fiber membrane oxygenators. The model is analogous to one developed previously for predicting O(2) transfer. A mass transfer correlation was determined in water for O(2) and CO(2) exchange and collapsed onto one universal curve. The correlation was used to predict CO(2) removal in blood by incorporating a 'facilitated diffusivity' to account for the transport of CO(2) present as bicarbonate. The diffusion of bicarbonate greatly increased the ability of the oxygenator to remove CO(2) in blood compared to water. A fiber bundle module was fabricated to test the model predictions. The fiber bundle had a length of 13 cm and a bundle thickness of 0.2 cm. The module was tested in bovine blood at flowrates of 0.75, 1.5, and 2.2 L/min and CO(2) removal rate predictions were within 9% of experimental measurements at all flowrates. The O(2) transfer rate predictions were within 10% of experimental measurements. A second module was manufactured with a bundle of length 4 cm and thickness of 1 cm. The CO(2) removal predictions were within the standard deviation of the experimental measurements.