A nurse is caring for a 2 month old infant who has had projectile vomiting for several days and is admitted to the pediatric unit. The infant's mucous membranes are dry and his anterior fontanel is depressed. Diagnostic results from his ultrasound shows that the infant has pyloric stenosis, Which of the following priority actions should the nurse take?

Rationale:

A. Magnesium is incorrect as the highest priority because, although furosemide can increase renal excretion of magnesium, hypomagnesemia is less immediately life-threatening compared with hypokalemia. Low magnesium can contribute to cardiac arrhythmias, but monitoring magnesium is generally secondary to monitoring potassium in acute management of heart failure.

B. Calcium is incorrect because loop diuretics like furosemide can increase calcium excretion, potentially leading to hypocalcemia over time. However, calcium disturbances are usually gradual and less acutely dangerous than potassium imbalances, so they are not the priority concern in a client at risk for cardiac complications.

C. Sodium is incorrect because furosemide can cause hyponatremia by promoting sodium loss in the urine. While significant sodium depletion can lead to neurological symptoms (confusion, seizures) and fluid imbalance, the risk of sudden, life-threatening cardiac arrhythmias is greater with potassium loss, making potassium monitoring more urgent.

D. Potassium is correct because furosemide potently increases renal potassium excretion, which can result in hypokalemia. Potassium is essential for normal cardiac conduction, and deficiency can quickly lead to ventricular dysrhythmias, cardiac arrest, muscle weakness, and fatigue. Monitoring potassium, assessing ECG changes, and providing dietary supplementation or medication adjustments are critical to prevent these potentially fatal complications.

Rationale:

A. Request a dietitian consult is incorrect because dietary modifications may be important for a child with congestive heart failure, but this is not the immediate priority when the client is showing potential signs of digoxin toxicity.

B. Check the client's vital signs is correct because nausea, vomiting, and weakness in a child taking digoxin can indicate digoxin toxicity, which can affect heart rate and rhythm. The nurse should first assess vital signs, particularly the heart rate, as digoxin toxicity can cause bradycardia or other dysrhythmias, which may be life-threatening. Assessment is always the first step according to the nursing process and the principle of safety first.

C. Request an order for an antiemetic is incorrect because treating symptoms without assessing the client could mask a potentially serious medication-related complication. Administering an antiemetic would not address the underlying risk of toxicity.

D. Suggest that the client rests before eating the meal is incorrect because resting does not address the potential danger of digoxin toxicity. Weakness and nausea may indicate cardiac compromise, so immediate assessment is necessary before implementing comfort measures.