Which of the following signs would indicate that a patient may be in respiratory distress?

The use of abdominal muscles to assist in breathing is a clear indicator that a patient may be experiencing respiratory distress. When a patient is in respiratory distress, they often have difficulty fully engaging the diaphragm – the primary muscle used for breathing. This difficulty can lead them to recruit accessory muscles, including those in the abdominal region, to help facilitate breathing. This pattern of using additional muscles is a physiological response to increased effort required for adequate ventilation and can indicate that the patient is struggling to get enough oxygen.

In contrast, normal skin color suggests that the patient has adequate oxygenation and is not in respiratory distress. Delayed capillary refill may signal other circulatory issues but is not a direct sign of respiratory distress. Increased physical activity tolerance would indicate that the patient is likely not in distress, as individuals experiencing breathing difficulties typically have reduced tolerance for exertion due to inadequate airflow or oxygenation. Therefore, the correct choice emphasizes the use of abdominal muscles as a significant and observable sign of respiratory compromise.