A cannulation device is disclosed, having a fixed blade, a retractable wedge, and an adjustment nut for mating with a cannula or a cannula assembly. Another cannulation device is disclosed, having a tube with proximal and distal ends. The fixed blade, coupled to the distal end of the tube, comprises a transition edge configured to cover a lead edge of a cannula. The cannulation device has a control rod movable within the tube； a retractable wedge； an actuator coupled to the control rod； and is configured to move the retractable wedge from a piercing position, where the retractable wedge is aligned with the fixed blade, to a retracted position where the retractable wedge has been retracted within the tube. The cannulation device has a cannula adapter and an adjustment nut movable to change a distance between the adjustment nut and the fixed blade.
