A blood processing apparatus includes a housing, a shell, a fiber bundle, and an elastic tube. The housing has a blood inlet and a blood outlet and the shell is situated in the housing and configured to receive blood through the blood inlet. The shell includes a surface and one or more apertures extending through the surface to permit the blood to flow to an exterior of the shell. The fiber bundle includes gas exchanger hollow fibers situated about the shell such that gas flows through and the blood flows across the gas exchanger hollow fibers. The elastic tube includes a fiber web situated about the fiber bundle and configured to elastically constrain and protect the gas exchanger hollow fibers during the insertion into the housing. The fiber web has a pore size that permits the blood to flow across the fiber web without filtering micro-emboli from the blood.