an elongated, non-porous tube having a uniform, non-expandable diameter with a substantially consistent cross-sectional size between a proximal end and a closed distal end, said proximal end of said tube configured to be connectable to a supply of fluid located external of a body of a patient in which said catheter is placed, said tube having a plurality of exit holes in side walls of said tube, said exit holes provided along a length of said tube defining an infusion section of said catheter, said tube being sized to be inserted into an anatomical region;

an elongated member permanently positioned within said tube, said elongated member being sized so that an annular space is formed between said tube and said elongated member, said elongated member being formed of a porous material that becomes saturated with a fluid introduced within said tube, wherein the porous material of the elongated member is configured to expand when the elongated member is saturated; and

an annular member disposed near the proximal end of said infusion section and configured to substantially prevent fluid introduced within said tube from entering said infusion section without first passing through said elongated member;

wherein said catheter is configured so that a fluid introduced into a proximal end of said tube will flow through said exit holes at a substantially uniform rate throughout said infusion section.