A catheter stop includes an obstruction attached to a catheter at a location that represents the maximum acceptable insertion depth of the catheter into a tracheal tube without causing damage to a patient or the tube. In one embodiment, the obstruction is a pad having a pair of opposing adhesive wings for securing the pad to the catheter. In another embodiment, the obstruction is formed of a triangular housing having a pair of hinged sections that open and close in a clamshell-type fashion. Each section includes a longitudinal, semi-cylindrical, bore that cooperates with the bore on the other section to form a tubular passageway for accommodating the catheter when the sections are closed. A clamp on an edge of one section detachably engages a latch on the corresponding edge of the other section to secure the housing about the catheter.
