Catheterization device and associated assembly

A catheterization device comprises a catheter, a hollow hypodermic needle longitudinally traversing the catheter, and a pressure detector and indicator attached to the needle at a proximal end thereof for sensing pressures inside a patient upon insertion of a distal tip of the needle into the patient and for qualitatively indicating the sensed pressure. The pressure detector and indicator includes an at least partially transparent housing, a fluid in the housing communicating with a lumen of the needle, and a movable indicator element such as a styrofoam sphere disposed in the fluid in the housing.