A nurse is caring for a 6-month-old infant who has a prescription for clear liquids by mouth after a repair of an intussusception. Which of the following fluids should the nurse select for the infant?

Choice A reason: Ridged abdomen is not an expected finding for an infant who has pyloric stenosis, as it indicates abdominal rigidity or guarding, which can be a sign of peritonitis or bowel obstruction. Pyloric stenosis is a narrowing of the pyloric sphincter, which causes gastric outlet obstruction and delayed gastric emptying.

Choice B reason: Red currant jelly stools are not an expected finding for an infant who has pyloric stenosis, as they indicate blood and mucus in the stools, which can be a sign of intussusception or necrotizing enterocolitis. Pyloric stenosis does not affect the lower gastrointestinal tract, and the infant may have constipation or dehydration due to vomiting.

Choice C reason: Projectile vomiting is an expected finding for an infant who has pyloric stenosis, as it occurs after feeding due to the increased pressure in the stomach and the inability to pass food into the duodenum. Projectile vomiting can cause weight loss, dehydration, electrolyte imbalance, and metabolic alkalosis.

Choice D reason: Distended neck veins are not an expected finding for an infant who has pyloric stenosis, as they indicate increased central venous pressure, which can be a sign of heart failure or superior vena cava syndrome. Pyloric stenosis does not affect the cardiovascular system, and the infant may have sunken fontanels or poor skin turgor due to dehydration.

Choice A reason: This test will confirm if your child had a recent streptococcal infection, as it measures the level of antibodies that the body produces against the streptolysin O enzyme, which is produced by some strains of streptococcal bacteria. A high ASO titer indicates a recent or current streptococcal infection, which can trigger rheumatic fever in some children.

Choice B reason: This test will not indicate if your child has rheumatic fever, as it does not measure the inflammation or damage to the heart, joints, or other organs that rheumatic fever can cause. Rheumatic fever is diagnosed based on the presence of two major or one major and two minor criteria, as well as evidence of a preceding streptococcal infection.

Choice C reason: This test will not indicate if your child has a therapeutic blood level of an aminoglycoside, as it does not measure the concentration of this type of antibiotic in the blood. Aminoglycosides are used to treat serious infections caused by gram-negative bacteria, and their blood levels need to be monitored to prevent toxicity and ensure efficacy.

Choice D reason: This test will not confirm if your child has immunity to streptococcal bacteria, as it does not measure the level of protective antibodies that can prevent future infections. ASO antibodies are not protective, but rather indicate a past or present exposure to streptococcal bacteria.