Abstract: Micro-conduit with enhanced wetting characteristics for use in providing a blood heat exchanger apparatus with improved heat exchange capability. The micro-conduit comprises a plurality of elongated fibers, which may be made of a hydrophobic material such as polypropylene or polyethylene. Each fiber is open at two opposing ends, and has an inner surface between the open ends. The inner surface is coated with a wetting agent, such as phosphatidyl choline or another ampiphilic material with a hydrophilic end and a hydrophobic end. The fibers may have a shape and size that without presence of the wetting agent, would otherwise substantially impair free passage of water. The micro-conduit may be provided as a heat exchanger micro-conduit wrapping material, wherein micro-conduit fibers are attached to a thin flexible interconnect, such as woven netting, to maintain the fibers at predetermined spacings in substantially parallel alignment with each other.