An infant born 2 days ago has not passed a meconium stool and begins to vomit bilious secretions. Which action should the nurse take first?

Choice A reason: Measuring abdominal circumference provides immediate, objective data about the degree of abdominal distention, which is a key sign of intestinal obstruction in a neonate who hasn’t passed meconium and is vomiting bilious secretions. Establishing a baseline girth measurement guides further assessment, helps detect rapidly worsening distention, and informs decisions about decompression and imaging studies. Choice B reason: Although initiating an IV infusion is critical for fluid and electrolyte replacement in any vomiting infant, securing intravenous access should follow a focused assessment. Prioritizing assessment ensures you understand the severity of the obstruction and tailor fluid resuscitation and other interventions appropriately. Choice C reason: Monitoring strict urinary output is not the first action that the nurse should take. This is because urinary output is not the most sensitive indicator of fluid status in infants, especially those with renal insufficiency or oliguria. Monitoring urinary output may also delay more urgent interventions, such as fluid resuscitation and decompression. Choice D reason: Preparing for anorectal manometry is not the first action that the nurse should take. This is because anorectal manometry is a diagnostic test that measures the pressure and function of the anal and rectal muscles. It is not indicated for infants with suspected meconium ileus, which is a mechanical obstruction of the bowel by thick and sticky meconium. Preparing for anorectal manometry may also delay more urgent interventions, such as fluid resuscitation and decompression.