An integrated catheter assembly includes a housing member, an outer lumen member extending from the housing member, and a needle member having a needle slidably or movably coupled to the housing member, wherein the needle can be extended beyond the outer lumen member. Once a flash of blood is confirmed the needle member is uncoupled from the housing member and removed from within the patent's vein or artery. Two separate passageways are established by the inner and outer lumen members passing through the housing member. In this manner the two passageways permit the simultaneous flow of fluids into or out of a body from a single target site, such as blood, medications and other fluids.