Which of the following is a sign of respiratory distress?

Cyanosis is a clinical sign that indicates a lack of oxygen in the bloodstream, which often signifies respiratory distress. It manifests as a bluish tint to the skin, lips, or nail beds and is a direct result of inadequate oxygenation, which can occur in various respiratory conditions such as asthma, COPD, or pulmonary edema. Recognizing cyanosis as a sign of respiratory distress is crucial for timely intervention and management, as it can be indicative of severe underlying issues that require immediate attention.

In contrast, the other options do not typically reflect respiratory distress. A regular pulse indicates a stable heart rhythm and is generally not a direct sign of respiratory issues. Elevated blood pressure can occur in various contexts but is not specific to respiratory distress. Clear skin, while often a sign of good circulation and oxygenation, does not provide information about respiratory function. Hence, the presence of cyanosis is a reliable indicator of distress in the respiratory system.