A nurse is caring for an infant who has heart failure and is receiving digoxin. Which of the following findings indicates a positive response to the medication?

The clinical scenario focuses on evaluating the therapeutic effectiveness of digoxin in an infant with heart failure. Knowledge of digoxin as a positive inotrope and negative chronotrope is required to assess improved cardiac output and systemic perfusion. Choice A rationale . Digoxin slows the heart rate to improve ventricular filling time. An infant's normal heart rate is 100 to 160 beats/min. A rate of 187/min indicates tachycardia, suggesting heart failure is not yet controlled or compensated. Choice B rationale . A respiratory rate within the normal infant range of 30 to 50 breaths/min indicates reduced pulmonary congestion. Digoxin increases cardiac output, which decreases fluid backup in the lungs, thereby lowering the effort and rate of breathing. Choice C rationale . Normal urine output for an infant is 1 to 2 mL/kg/hr. While this value is within the normal range, it is not the most definitive sign of digoxin's positive effect compared to a decrease in respiratory distress. Choice D rationale . Normal capillary refill time in an infant is less than 2 seconds. A refill time of 4 seconds indicates poor peripheral perfusion and low cardiac output, suggesting that the digoxin has not yet achieved a positive therapeutic effect.