A nurse is caring for a 6-week-old infant admitted to the pediatric unit for evaluation of a suspected pyloric stenosis. Which of the following findings should the nurse expect?

To predict the expected weight of the 12-month-old boy, we can use the general guideline that a child's weight should triple from birth to 12 months.

Given that the boy weighed 8 lb 2 oz at birth, we can calculate the expected weight at 12 months by tripling this weight.

8 lb 2 oz = 8.125 lb

Tripling this weight:

8.125 lb * 3 = 24.375 lb

Now, we convert this weight back to pounds and ounces:

0.375 lb * 16 = 6 oz

So, the expected weight of the 12-month-old boy should be approximately 24 lb 6 oz.

A. Projectile vomiting

Projectile vomiting is a classic symptom of pyloric stenosis in infants. It typically occurs within 30 minutes of feeding and is forceful, often projecting several feet away from the infant. This occurs due to the obstruction at the pyloric sphincter, leading to the stomach forcefully emptying its contents.

B. Metabolic acidosis

Metabolic acidosis is not a typical finding associated with pyloric stenosis. Pyloric stenosis leads to vomiting, which can result in dehydration and electrolyte imbalances, but it typically does not cause metabolic acidosis directly.

C. Effortless regurgitation

Effortless regurgitation is not a characteristic finding of pyloric stenosis. In pyloric stenosis, vomiting is forceful and projectile, rather than a passive regurgitation of stomach contents.

D. Distended abdomen

A distended abdomen can be a finding in pyloric stenosis. The obstruction at the pyloric sphincter can lead to gastric retention, causing the stomach to become distended over time. However, it's important to note that not all infants with pyloric stenosis will present with a visibly distended abdomen.