A client has just returned to the nursing unit following cardiac catheterization. In the immediate postprocedure period, which of the following is the priority nursing action?

A. Monitoring the insertion site for infection:
Monitoring for infection is important in the long-term care of a client following cardiac catheterization, but it is not the immediate priority. Infection typically develops over time, not in the immediate postprocedure period.

B. Checking for orthostatic hypotension:
Orthostatic hypotension is not typically associated with cardiac catheterization. Instead, hypotension following the procedure would likely result from bleeding or hypovolemia. Monitoring for vital sign changes is important but not specific to orthostatic hypotension in this context.

C. Forcing fluids:
Encouraging fluids is necessary after cardiac catheterization to help flush out contrast dye and prevent nephropathy. However, this action is not the immediate priority compared to managing the risk of bleeding and maintaining hemostasis at the insertion site.

D. Immobilizing the affected extremity:
Immobilizing the extremity used for catheter insertion (usually the femoral artery) is the immediate priority. This action prevents complications such as bleeding, hematoma formation, or disruption of the arterial puncture site. Maintaining hemostasis and ensuring the integrity of the insertion site are critical during the immediate postprocedure period.