An extracorporeal system for lung assist includes a system housing, which includes a blood flow inlet and a blood flow outlet and a fiber bundle housing movably positioned within the system housing. The fiber bundle housing includes a gas inlet and a gas outlet. A fiber bundle is in operative connection with the fiber bundle housing. The fiber bundle includes a plurality of hollow gas permeable fibers, wherein lumens of the plurality of hollow gas fibers are in fluid connection with the gas inlet at a first end thereof and in fluid connection with the gas outlet as a second end thereof. The system further includes an actuator to impart oscillatory motion to the fiber bundle housing and thereby to the fiber bundle.