An extracorporeal system for lung assist comprising: a housing, the housing comprising a blood flow inlet in fluid connection with a pressurizing stator compartment, a fiber bundle compartment in fluid connection with the pressurizing stator compartment via a flow channel in fluid connection with an inlet manifold of the fiber bundle compartment, and a blood flow outlet in fluid connection with an outlet manifold of the fiber bundle compartment; an impeller rotatably positioned within the pressurizing stator compartment for pressurizing blood entering the pressurizing stator compartment from the blood flow inlet, the impeller centrifugally forcing blood radially outward into the flow channel; a fiber bundle positioned within the fiber bundle compartment, the fiber bundle comprising a plurality of hollow gas permeable fibers formed in at least one cylindrical bundle, the plurality of hollow gas permeable fibers being adapted to permit diffusion of gas between blood and an interior of the plurality of hollow gas permeable fibers, the plurality of hollow gas permeable fibers being positioned such that blood flows around the plurality of hollow gas permeable fibers when flowing through the fiber bundle compartment, the plurality of hollow gas permeable fibers extending perpendicular or within 5 degrees of perpendicular to an axis of the fiber bundle, the direction of bulk flow of blood through the fiber bundle being axially or within 5 degrees of axially therethrough, blood flowing through the fiber bundle compartment from the inlet manifold to the outlet manifold, a gas inlet in fluid connection with the housing and in fluid connection with inlets of the plurality of hollow gas permeable fibers, and a gas outlet in fluid connection with the housing and in fluid connection with outlets of the plurality of hollow gas permeable fibers. wherein an axis of the fiber bundle is oriented generally parallel or within 5 degrees of parallel to a plane of rotation of the impeller and the flow channel extends upward along a side of the housing from the pressurizing stator compartment to the inlet manifold so the blood is introduced into inlet manifold from the flow channel perpendicular to the axis of the fiber bundle. a housing, the housing comprising a blood flow inlet in fluid connection with a pressurizing stator compartment, a fiber bundle compartment in fluid connection with the pressurizing stator compartment via a flow channel in fluid connection with an inlet manifold of the fiber bundle compartment, and a blood flow outlet in fluid connection with an outlet manifold of the fiber bundle compartment; an impeller rotatably positioned within the pressurizing stator compartment for pressurizing blood entering the pressurizing stator compartment from the blood flow inlet, the impeller centrifugally forcing blood radially outward into the flow channel; a fiber bundle positioned within the fiber bundle compartment, the fiber bundle comprising a plurality of hollow gas permeable fibers formed in at least one cylindrical bundle, the plurality of hollow gas permeable fibers being adapted to permit diffusion of gas between blood and an interior of the plurality of hollow gas permeable fibers, the plurality of hollow gas permeable fibers being positioned such that blood flows around the plurality of hollow gas permeable fibers when flowing through the fiber bundle compartment, the plurality of hollow gas permeable fibers extending perpendicular or within 5 degrees of perpendicular to an axis of the fiber bundle, the direction of bulk flow of blood through the fiber bundle being axially or within 5 degrees of axially therethrough, blood flowing through the fiber bundle compartment from the inlet manifold to the outlet manifold, a gas inlet in fluid connection with the housing and in fluid connection with inlets of the plurality of hollow gas permeable fibers, and a gas outlet in fluid connection with the housing and in fluid connection with outlets of the plurality of hollow gas permeable fibers. wherein an axis of the fiber bundle is oriented generally parallel or within 5 degrees of parallel to a plane of rotation of the impeller and the flow channel extends upward along a side of the housing from the pressurizing stator compartment to the inlet manifold so the blood is introduced into inlet manifold from the flow channel perpendicular to the axis of the fiber bundle.