An access device for placing a medical article within a body space includes a syringe, a needle, and a sheath which are employed together with a guide wire. The sheath can be coaxially and slideably disposed about the needle. During insertion of the sheath over the needle, guide wire and into the body space, the syringe provides a negative pressure to ensure that any air located between the inside diameter of the sheath and the outside diameter of the needle is drawn into the needle rather than into the body space. In certain embodiments, a dilator is coaxially and slideably disposed about the needle and within the sheath.