An extravascular system includes a catheter assembly, a needle assembly, and a hemostatic adapter. The catheter assembly defines a lumen extending from an opening at a distal end thereof to a catheter hub at a proximal end thereof. The needle assembly includes a needle hub disposed at a proximal end of a needle disposed within the lumen defined by the catheter assembly. The needle has a needle tip extending from the opening of the catheter assembly. The hemostatic adapter defines a passage and is adapted to be operatively associated with the needle assembly and the catheter assembly. The hemostatic adapter further includes at least one liquid-reactive material adapted to at least substantially seal the passage upon contact with one or more liquids. The liquid-reactive material is selected and configured to morph upon contact with liquids to provide a mechanical barrier to prevent blood flow. A fluid may be injected into the lumen and/or passage by way of an optional port to provide a fluidic barrier in addition to the mechanical barrier.