A 6-week-old infant with poor weight gain is scheduled for a pyloromyotomy. Which pre-operative nursing action has the highest priority?

Choice A reason: Marking an outline of the "olive-shaped" mass in the right epigastric area is not a priority nursing action. The mass is caused by hypertrophy of the pyloric sphincter, which obstructs gastric emptying and causes projectile vomiting. The mass may not be palpable in all cases. Choice C reason: Monitoring amount of intake and infant's response to feedings is important, but not the highest priority. The infant may have difficulty feeding due to nausea, vomiting, and abdominal pain. Choice D reason: Instructing parents regarding care of the incisional area is a post-operative nursing action, not a pre-operative one. The parents will need to learn how to keep the incision clean and dry, monitor for signs of infection, and administer pain medication as prescribed.