Neonatal Nurse Practitioner Practice Exam

A high concentration of sodium in intravenous fluid can lead to decreased urine output in a neonate due to the body's response to hypernatremia. When sodium levels rise, it can create an osmotic gradient that causes fluid to shift from the intravascular space into the extracellular compartment and interstitial spaces. This shift may lead to cellular dehydration, encouraging the kidneys to conserve water in an attempt to balance sodium concentrations.

Additionally, the kidneys of neonates are not fully mature, which means they may have a harder time excreting excess sodium, leading to potential fluid overload and increased concentrations of sodium in the plasma. This situation can activate compensatory mechanisms that result in reduced glomerular filtration rate and further decrease urine output.

While other options like metabolic acidosis, fluid retention, and dehydration might intuitively seem relevant to sodium concentration, they do not as directly relate to the immediate renal response seen with elevated sodium levels. Therefore, decreased urine output is the most accurate outcome in this scenario.