Tens of thousands of Americans and Veterans with end stage lung disease (ESLD) are not candidates for lung transplant and thus are doomed to suffer a long and miserable death from dyspnea, limitation of activity, and eventually total respiratory failure. The long-term goal of this technology-development project is to improve rehabilitation from lung disease by developing artificial lung systems that automatically and rapidly compensate for the changing respiratory and metabolic needs of the patient, thereby increasing patient health, comfort, activity, and ability to exercise and rehabilitate. The objectives of the current proposal are to: 1) develop a control system for an artificial lung system featuring sweep gas servoregulation to adjust CO2 removal based on patient need; and, 2) evaluate the control system in animal models. At the completion of this project, we expect to be ready to integrate the developed control system with various artificial lung systems and prostheses that will, for the first time, enable large changes in patient activity during rehabilitation and daily life.