What should the nurse do after confirming blood return during the insertion of an over-the-needle catheter?

After confirming blood return during the insertion of an over-the-needle catheter, lowering the catheter until it is flush with the skin is the correct action. This step is crucial because it allows the nurse to stabilize the catheter correctly and ensures that it is positioned properly within the vein. Once blood return is confirmed, the presence of blood in the catheter indicates that the needle is appropriately placed within the vessel. Lowering the catheter helps to achieve a secure and effective venous access, minimizing the risk of dislodgment or complications.

In contrast, withdrawing the catheter immediately after confirming blood return would not be appropriate, as it would nullify the successful venipuncture achieved. Increasing the angle of insertion is unnecessary since the vein access has already been confirmed, and such an adjustment could lead to complications. Finally, completely removing the needle before inserting the catheter is not advisable, as it would erase any confirmation of venous access gained through blood return.