Which is the priority nursing action when initiating morphine therapy via an intravenous patient-controlled analgesia (PСА) pump?

A. Assess the abdomen for bowel sounds: Monitoring bowel sounds is important during opioid therapy because morphine can cause constipation. However, this assessment does not take priority when initiating PCA therapy, as it does not immediately affect safe administration or pain control. B. Initiate the dosage lockout mechanism on the PCA pump: The lockout mechanism is the most critical safety feature of a PCA pump. It prevents the client from administering a second dose of medication before the first dose has had time to take effect. By strictly limiting the frequency of doses (e.g., a 6-to-10-minute lockout period), the pump prevents accidental overdose and toxicity. While all the listed options are part of the nursing process, ensuring the mechanical safety of the high-alert medication delivery system is the priority during the initiation phase. C. Instruct the client to use the medication before the pain becomes severe: Teaching about preemptive use improves pain control and prevents breakthrough pain, but this instruction is most effective after determining that the client can understand and use the PCA system appropriately. D. Assess the client's ability to use a numeric pain scale: The nurse must ensure the client can communicate their pain level to evaluate the effectiveness of the therapy. However, this is a baseline assessment that should ideally occur before the initiation of the pump. It does not carry the same immediate safety weight as securing the pump's lockout mechanism.