Final answer:
The nurse should first attend to the postoperative client with a blood pressure of 90/50, as it may be indicative of a serious condition such as hypotension or shock.
Step-by-step explanation:
The nurse should prioritize seeing the postoperative client who has a documented blood pressure of 90/50. This may indicate hypotension, which can be a sign of hemorrhage or other serious complications after surgery. Immediate assessment and potential intervention are critical to the patient's safety. The other clients require attention for pain management, assistance with ambulation, and pre-discharge education, but these are not as immediately life-threatening as potential shock or significant blood pressure abnormalities.