What is a sign of fatigue in a patient with respiratory distress?

Labored breathing is a sign of fatigue in a patient experiencing respiratory distress because it indicates that the patient is struggling to breathe effectively. This struggle often leads to increased use of the accessory muscles and can result in visible effort, such as grunting or the use of neck and shoulder muscles during inhalation. As the body fatigues, the ability to maintain effective breathing diminishes, and the patient may exhibit labored breathing as a consequence of their respiratory fatigue. This can signify that the respiratory muscles are becoming exhausted and that the patient may need immediate medical intervention to support their breathing.

In contrast, while increased respiratory rate and shallow breathing can also indicate distress, they are not as directly associated with fatigue as labored breathing is. A weak pulse is unrelated to respiratory efforts and more indicative of circulatory issues rather than a direct sign of respiratory fatigue.