Immobilized carbonic anhydrase in a membrane lung for enhanced CO2 removal.

The potential use of carbonic anhydrase (CA), immobilized within membrane lungs, to accelerate the removal of CO2 from blood was investigated. Using a variation on the technique of Chang, 500 micrograms/mL of CA was encapsulated in 5-20 microns cellulose nitrate microcapsules which were then immobilized onto a 0.1 m2 silicone rubber membrane. Using an in vitro test circuit, 0.68 mmol/m2/min of CO2 was removed from venous blood through an untreated membrane at steady state. With the CA-immobilized membrane, CO2 removal was enhanced to 1.09 mmol/m2/min. This technique has the potential of greatly improving the CO2 efficiency of commercial membrane lungs for ECCOR.