Final answer:
A client who is 6 hours postoperative following an AAA repair and presents with a distended, tender abdomen requires immediate intervention, as this could indicate a serious complication like hemorrhage or bowel perforation.
Step-by-step explanation:
Among the assessment data provided for a client who is 6 hours postoperative following an Abdominal Aortic Aneurysm (AAA) repair, the most concerning and requiring immediate intervention by a nurse would be a 'distended, tender abdomen.' This could indicate a possible complication such as hemorrhage or bowel perforation, both of which demand urgent attention. While an elevated temperature and complaints of pain are notable and require monitoring and management, they do not typically signify an emergency at this level. Absent bilateral pedal pulses are also worrisome, as they may reflect vascular compromise; however, the presence of a distended, tender abdomen is the most acute sign and thus takes precedence for immediate intervention.