A postoperative client returns to the nursing unit following a ureterolithotomy via a flank incision. Which potential problem has the highest priority when planning nursing care for this client?

A. Altered nutrition is a concern but is not the immediate priority. B. Activity intolerance is expected but does not pose an immediate threat. C. Fluid volume excess should be monitored, but ineffective airway clearance poses a more immediate risk. D. Ineffective airway clearance is the highest priority because a flank incision can cause significant pain, leading to shallow breathing and increased risk for atelectasis or pneumonia.