Which of the following is a key indicator of shock?

A key indicator of shock is pale skin, which occurs as the body redirects blood flow to vital organs in response to decreased circulation due to shock. When the body is in a state of shock, it activates compensatory mechanisms that can lead to vasoconstriction, limiting blood flow to the skin and resulting in a pale or ashen appearance. This change in skin color is a visible sign of the body's struggle to maintain proper blood circulation and oxygenation.

In contrast, the other indicators mentioned do not align with the physiological changes typically observed during shock. For instance, increased urinary output would be contrary to shock conditions, as the body tends to conserve fluid and urine production often decreases. Elevated blood pressure is also not indicative of shock; in fact, blood pressure may actually drop during shock states as the heart struggles to pump effectively. Lastly, a normal pulse rate is not typical; tachycardia, or an increased heart rate, often occurs as the body attempts to compensate for the reduced blood volume and pressure seen in shock. Each of these indicators is a response that varies from the expected signs of shock, reinforcing the diagnostic importance of pale skin in identifying this critical condition.