An injection port assembly including a body having first and second mating structures configured to mate with a first connector for a first fluid pathway and a second connector on a device, respectively. A resilient barrier substantially contained within the body and compressible from a first position in which fluid flow between the first and second connectors is blocked to a more compressed second position in which fluid flow between the first and second connectors is permitted. A hollow cannula can be coupled with the first mating structure and disposed within the resilient barrier, the hollow cannula having a distal end configured to extend through the resilient barrier when the resilient barrier is in the second position, the distal end having lateral slots. The resilient barrier can have first and second annular sealing rings positioned above and below the lateral slots respectively.