A catheter assembly may include a catheter adapter, which may include a distal end, a proximal end, and a lumen extending through the distal end and the proximal end of the catheter adapter. The catheter assembly may include a septum disposed within the lumen, a septum actuator fixed within the lumen, and a spring disposed within the lumen distal to the septum. The septum may include a distal end, a proximal end, and a barrier that may divide an interior of the septum into a distal cavity and a proximal cavity. In response to insertion of a medical device into the proximal end of the catheter adapter, the septum may move from a proximal position to a distal position, and the septum actuator may penetrate the septum. The spring may return the septum from the distal position to the proximal position in response to removal of the medical device.
