How can you tell if an infant is in respiratory distress?

An infant in respiratory distress may exhibit specific physical signs that indicate difficulty in breathing. One of the hallmark signs is grunting, which occurs as the infant attempts to increase airway pressure and improve oxygenation. Flaring of the nostrils is another critical observation, as it indicates that the infant is trying to take in more air due to inadequate oxygen supply. Additionally, retractions occur when the chest wall is sucked inward during inhalation, showing that the infant is struggling to breathe.

These signs are crucial for identifying respiratory distress and warrant immediate medical evaluation. The other options do not directly reflect the physiological signs associated with respiratory distress in infants. For instance, refusal to eat could occur for several reasons, while appearing calm and relaxed would be counterintuitive in the context of distress. A rapid heartbeat can be a systemic response but may not be specific enough alone to indicate respiratory distress. Thus, the presence of grunting, nostril flaring, and retractions provides a clear and immediate understanding of an infant's respiratory condition.