A catheter assembly may include a cannula. The cannula may include a distal tip, an elongated tubular shaft, and an inner lumen formed by the elongated tubular shaft. A first portion of the elongated tubular shaft may have a first outer diameter. The first portion may be proximate the distal tip. A second portion of the elongated tubular shaft may have a second outer diameter. The second outer diameter may be greater than the first outer diameter. The catheter assembly may also include a catheter adapter, which may include a catheter and a catheter hub. The second portion of the elongated tubular shaft may be at least partially disposed in the catheter hub.