A nurse is caring for a client who has a prescription for a peripheral IV catheter. After puncturing the skin with the vascular access device and noting a blood return in the flashback chamber, which of the following actions should the nurse perform next?

The correct answer is D: Advance the catheter into the vein. After noting blood return in the flashback chamber, the next step is to advance the catheter into the vein to ensure proper placement and secure the IV access. This step is crucial to prevent infiltration or dislodgement of the catheter. Releasing the tourniquet (choice A) is not the immediate next step. Retracting the stylet (choice B) is done after advancing the catheter. Flushing the catheter with saline (choice C) should be done after securing the catheter in the vein. Therefore, the correct sequence of actions is to advance the catheter into the vein first.