Final answer:
The nurse should first assess the post-operative client with a PCA for respiratory distress due to the presentation of restlessness, tachycardia, and hypotension, which could be signs of opioid-induced respiratory depression or other serious complications.
Step-by-step explanation:
The question concerns a post-operative client with a Patient-Controlled Analgesia (PCA) who exhibits restlessness, an elevated pulse, and decreased blood pressure (BP). Among the options provided, the most appropriate initial action for the nurse would be to c) assess for respiratory distress. When a patient shows signs of restlessness, tachycardia (elevated pulse), and hypotension (decreased BP), it can be indicative of various complications, including but not limited to, pain, bleeding, or respiratory issues such as opioid-induced respiratory depression, which is a serious risk associated with PCA use. Before taking any other action, such as administering more medication or adjusting the dose, the nurse should assess the patient's respiratory status to ensure safety. If respiratory distress is present, the nurse should follow the appropriate protocols, which may include notifying the physician and managing the patient's airway.