Final answer:
The first intervention for a client exhibiting signs of fluid overload should be to decrease the IV fluids to a keep vein open rate. This response is dictated by the immediate need to address potential life-threatening complications such as pulmonary edema.
Step-by-step explanation:
The intervention that the nurse should implement first for a client receiving a continuous infusion of normal saline post abdominal surgery, who is drowsy, complaining of constant abdominal pain, a headache, and showing signs of fluid overload, is b. Decrease IV fluids, to keep vein open rate. The presence of respiratory crackles, bounding central pulses, and elevated central venous pressure (CVP) indicates that the patient may be experiencing fluid overload. Starting with this intervention aligns with addressing the most critical signs of potential complications, such as pulmonary edema or congestive heart failure, which are life-threatening. Reviewing the last administration of IV pain medication and administering a PRN dose of acetaminophen may be important for comfort and fever but are not as immediately critical as managing the fluid status. Calculating total intake and output is essential for overall management but is not the immediate first step in stabilizing the patient.