Systems and methods for sealing and venting a septum of an intravenous catheter device. Implementations of the present invention include a compact, molded septum that is retained within an inner lumen of a catheter adapter such that slowed or stopped flow of air and/or a fluid is permitted to pass between the compact septum and an inner wall surface of the catheter adapter via one or more fluid pathways. In some instances, a snap ring is provided to secure the position of the compact septum within the catheter adapter, a fluid pathway being provided through the snap ring.